The year 155 B.C. was signalised by an important event, if not in the history of ideas, at least in the history of their diffusion. This was the despatch of an embassy from the Athenian people to the Roman Senate, consisting of three philosophers, the heads of their respective schools—Carneades the Academician, Critolaus the Peripatetic, and Diogenes the Stoic. Philosophic teaching, once proscribed at Athens, had, at the time of which we are speaking, become her chief distinction, and the most honourable profession pursued within her precincts. It was, then, as natural that an important mission should be confided to the most eminent representatives of the calling in question as that high ecclesiastics should be similarly employed by Rome in later ages, or that German university towns should send professors to represent their interests in the imperial Diet. But the same fate that befalls an established religion had befallen an established philosophy. An attempt to impose restrictions on the liberty of teaching had, indeed, been successfully resisted, and the experiment was never repeated.212 Nevertheless, the teachers themselves lost as much in true dignity as they gained in affluence and popular estimation. In all probability, the threat of death would not have induced Socrates to undertake the task which was, apparently, accepted without compulsion and as an honourable duty by his successors. The Athenians had made an unprovoked raid on the town of Oropus; the affair had been referred to arbitration; and the aggressors had been sentenced to pay a fine of 500 talents. It was to obtain a remission of this sentence that the three Scholarchs were sent on an embassy to the Roman Senate.

If the nature of their errand was not precisely calculated to win respect for the profession of the Athenian envoys, the subsequent proceedings of one among their number proved still less likely to raise it in the estimation of those whose favour they sought to win. Hellenic culture was, at that time, rapidly gaining ground among the Roman aristocracy; Carneades, who already enjoyed an immense reputation for eloquence and ingenuity among his own countrymen, used the opportunity offered by his temporary residence in the imperial city to deliver public lectures on morality; and such was the eagerness to listen that for a time the young nobles could think and talk of nothing else. The subject chosen was justice. The first lecture recapitulated whatever had been said in praise of that virtue by Plato and Aristotle. But it was a principle of the sect to which Carneades belonged that every affirmative proposition, however strongly supported, might be denied with equal plausibility. Accordingly, his second discourse was entirely devoted to upsetting the conclusions advocated in the first. Transporting the whole question, as would seem, from a private to a public point of view, he attempted to show, from the different standards prevailing in different countries, that there was no such thing as an immutable rule of right; and also that the greatest and most successful States had profited most by unscrupulous aggressions on their weaker neighbours—his most telling illustrations being drawn from the history of the Romans themselves. Then, descending once more to private life, the sceptical lecturer expatiated on the frequency of those cases in which justice is opposed to self-interest, and the folly of sacrificing one’s own advantage to that of another. ‘Suppose a good man has a runaway slave or an unhealthy house to sell, will he inform the buyer of their deficiencies, or will he conceal them? In the one case he will be a fool, in the other case he will be unjust. Again, justice forbids us to take away the life or property of another. But in a shipwreck, will not the just man try to save his life at another’s expense by seizing the plank of which some weaker person than himself has got hold—especially if they are alone on the sea together? If he is wise he will do so, for to act otherwise would be to sacrifice his life. So also, in flying before the enemy, will he not dispossess a wounded comrade of his horse, in order to mount and escape on it himself? Here, again, justice is incompatible with self-preservation—that is to say, with wisdom!‘213

At the time when Carneades delivered his lectures, the morality of Rome resembled that of Sparta during her great conflict with Athens, as characterised by one of the speakers in the Melian Dialogue. Scrupulously honourable in their dealings with one another, in their dealings with foreign nations her citizens notoriously identified justice with what was agreeable or advantageous to themselves. The arguments of the Academic philosopher must, therefore, have been doubly annoying to the leaders of the State, as a satire on its public policy and as a source of danger to the integrity of its private life. In this respect, old Cato was a type of the whole race. In all transactions with his fellow-citizens, and in every office undertaken on behalf of the community, his honesty was such that it became proverbial. But his absolute disregard of international justice has become equally proverbial through the famous advice, reiterated on every possible occasion, that an unoffending and unwarlike city should be destroyed, lest its existence should at some future time become a source of uneasiness to the mistress of the world. Perhaps it was a secret consciousness of his own inconsistency which prevented him from directly proposing that Carneades should not be allowed to continue his lectures. At any rate, the ex-Censor contented himself with moving that the business on which the Athenian envoys had come should be at once concluded, that they might return to their classes at Athens, leaving the youth of Rome to seek instruction as before from the wise conversation and example of her public men.214 We are not told whether his speech on this occasion wound up with the usual formula, caeterum, Patres Conscripti, sententia mea est Carthaginem esse delendam; but as it is stated that from the year 175 to the end of his life, he never made a motion in the Senate that was not terminated by those words, we are entitled to assume that he did not omit them in the present instance. If so, the effect must have been singularly grotesque; although, perhaps, less so than if attention had been drawn to the customary phrase by its unexpected absence. At any rate, Carneades had an opportunity of carrying back one more illustration of ethical inconsistency wherewith to enliven his lectures on the ‘vanity of dogmatising’ and the absolute equilibrium of contradictory opinions.

It has been mentioned that Carneades was the head of the Academic school. In that capacity, he was the lineal inheritor of Plato’s teaching. Yet a public apology for injustice, even when balanced by a previous panegyric on its opposite, might seem to be of all lessons the most alien from Platonism; and in a State governed by Plato’s own laws, it would certainly have been punishable with death. To explain this anomaly is to relate the history of Greek scepticism, which is what we shall now attempt to do.

II.

In modern parlance, the word scepticism is often used to denote absolute unbelief. This, however, is a misapplication; and, properly speaking, it should be reserved, as it was by the Greeks, for those cases in which belief is simply withheld, or in which, as its etymology implies, the mental state connoted is a desire to consider of the matter before coming to a decision. But, of course, there are occasions when, either from prudence or politeness, absolute rejection of a proposition is veiled under the appearance of simple indecision or of a demand for further evidence; and at a time when to believe in certain theological dogmas was either dangerous or discreditable, the name sceptic may have been accepted on all hands as a convenient euphemism in speaking about persons who did not doubt, but denied them altogether. Again, taken in its original sense, the name sceptic is applicable to two entirely different, or rather diametrically opposite classes. The true philosopher is more slow to believe than other men, because he is better acquainted than they are with the rules of evidence, and with the apparently strong claims on our belief often possessed by propositions known to be false. To that extent, all philosophers are sceptics, and are rightly regarded as such by the vulgar; although their acceptance of many conclusions which the unlearned reject without examination, has the contrary effect of giving them a reputation for extraordinary credulity or even insanity. And this leads us to another aspect of scepticism—an aspect under which, so far from being an element of philosophy, it is one of the most dangerous enemies that philosophy has to face. Instead of regarding the difficulties which beset the path of enquiry as a warning against premature conclusions, and a stimulus to more careful research, it is possible to make them a pretext for abandoning enquiry altogether. And it is also possible to regard the divergent answers given by different thinkers to the same problem, not as materials for comparison, selection or combination, nor even as indications of the various directions in which a solution is not to be sought, but as a proof that the problem altogether passes the power of human reason to solve.

Were this intellectual despondency to issue in a permanent suspense of judgment, it would be bad enough; but practically its consequences are of a much more mischievous character. The human mind is so constituted that it must either go forward or fall back; in no case can it stand still. Accordingly, the lazy sceptic almost always ends by conforming to the established creeds and customs of his age or of the society in which he lives; thus strengthening the hands of authority in its conflict with the more energetic or courageous enquirers, whose object is to discover, by the unaided efforts of reason, some new and positive principle either of action or of belief. And the guardians of orthodoxy are so well aware of the profit to be reaped from this alliance that, when debarred from putting down their opponents by law or by public opinion, they anxiously foster false scepticism where it is already rampant, and endeavour to create it where it does not exist. Sometimes disinterested morality is the object of their attack, and at other times the foundations of inductive science. Their favourite formula is that whatever objections may be urged against their own doctrines, others equally strong may be urged against the results of free thought; whereas the truth is that such objections, being applicable to all systems alike, exactly balance one another, leaving the special arguments against irrationalism to tell with as much force as before. And they also lay great stress on the internal dissensions of their assailants—dissensions which only bring out into more vivid relief the one point on which all are agreed, that, whatever else may be true, the traditional opinions are demonstrably false.

As might be expected from the immense exuberance of their intellectual life, we find every kind of scepticism represented among the Greeks; and, as with their other philosophical tendencies, there is evidence of its existence previous to or independent of scientific speculation. Their very religion, though burdened with an enormous mass of fictitious legends, shows a certain unwillingness to transgress the more obvious laws of nature, not noticeable in the traditions of kindred or neighbouring races. Its tendency is rather to imagine supernatural causes for natural events, or to read a divine meaning into accidental occurrences, than to introduce impossibilities into the ordinary course of history. And some of its most marvellous stories are told in such a manner that the incredulous satire with which they were originally received is, by a beautiful play of irony, worked into the very texture of the narrative itself. For example, the Greeks were especially disinclined to believe that one of the lower animals could speak with a human voice, or that a dead man could be brought back to life—contradicted as both suppositions were by the facts of universal experience. So when the horse Xanthus replies to his master’s reproaches, Homer adds that his voice was arrested by the Erinyes—that is to say, by the laws of nature; and we may suspect that nothing more is intended by his speech than the interpretation which Achilles would spontaneously put on the mute and pathetic gaze of the faithful steed. And when, to illustrate the wondrous medical skill of AsclÊpius, it is related that at last he succeeded in restoring a dead man to life, the story adds that for this impious deed both the healer and his patient were immediately transfixed by a thunderbolt from heaven.215 Another impossibility is to predict with any certainty the future fate of individuals, and here also—as has been already observed in a different connexion216—the Greeks showed their extreme scepticism with regard to any alleged contravention of a natural law, under the transparent disguise of stories about persons whom ambiguous predictions had lured to their fall.

It is even doubtful how far the Greek poets believed in the personality of their gods, or, what comes to the same thing, in their detachment from the natural objects in which a divine power was supposed to be embodied. Such a detachment is most completely realised when they are assembled in an Olympian council; but, as Hegel has somewhere observed, Homer never brings his gods together in this manner without presenting them in a ridiculous light—that is to say, without hinting that their existence must not be taken quite in earnest. And the existence of disembodied spirits seems to be similarly conceived by the great epic master. The life of the souls in Hades is not a continuance but a memory and a reflection of their life on earth. The scornful reply of Achilles to the congratulations of Odysseus implies, as it were, the consciousness of his own nonentity. By no other device could the irony of the whole situation, the worthlessness of a merely subjective immortality, be made so poignantly apparent.217

The characters in Homer are marked by this incredulous disposition in direct proportion to their general wisdom. When Agamemnon relates his dream to the assembled chiefs, Nestor dryly observes that if anyone of less authority had told them such a story they would have immediately rejected it as untrue. Hector’s outspoken contempt for augury is well known; and his indifference to the dying words of Patroclus is equally characteristic. In the Odyssey, Alcinous pointedly distinguishes his guest from the common run of travellers, whose words deserve no credit. That Telemachus should tell who is his father, with the uncomplimentary reservation that he has only his mother’s word for it, is evidently meant as a proof of the young man’s precocious shrewdness; and it is with the utmost difficulty that Penelope herself is persuaded of her husband’s identity. So in the Agamemnon of Aeschylus, nothing less than the report of an eye-witness will convince the Chorus of old men that Troy has really fallen.218 Finally, to complete the list of examples afforded independently of philosophical reflection, Herodotus repeatedly expresses disbelief in the stories told him, or, what is more remarkable, holds his judgment in suspense with regard to their veracity.

Scepticism, as a philosophical principle, is alien from early Greek thought; but it is pervaded by a negative tendency exhibited in four different directions, all converging towards the later attitude of suspensive doubt. There are sharp criticisms on the popular mythology; there are protests against the ascription of reality to sensible appearances; there are contemptuous references on the part of some philosophers to the opinions held by others; and there are occasional lamentations over the difficulty of getting at any truth at all. The importance, however, of these last utterances has been considerably exaggerated both in ancient and modern times. For, in some instances, they are attributable solely to the distrust of sense-perception, and in others they seem to express nothing more than a passing mood against which we must set the dogmatic conclusions elsewhere enunciated with perfect confidence by the same thinkers.219 At the same time, we have to note, as an illustration of the standing connexion between theological belief and that kind of scepticism which is shown by distrust in man’s power of discovering the truth for himself, that the strongest expressions of such a distrust are to be found in the two most religious of the pre-Socratic thinkers, Xenophanes and Empedocles.

III.

A new period begins with the Greek Humanists. We use this term in preference to that of Sophists, because, as has been shown, in specially dealing with the subject, half the teachers known under the latter denomination made it their business to popularise physical science and to apply it to morality, while the other half struck out an entirely different line, and founded their educational system on the express rejection of such investigations; their method being, in this respect, foreshadowed by the greatest poet of the age, who concentrates all his attention on the workings of the human mind, and followed by its greatest historian, with whom a similar study takes the place occupied by geography and natural history in the work of Herodotus. This absorption in human interests was unfavourable alike to the objects and to the methods of previous enquiry: to the former, as a diversion from the new studies; to the latter, as inconsistent with the flexibility and many-sidedness of conscious mind. Hence the true father of philosophical scepticism was Protagoras. With him, for the first time, we find full expression given to the proper sceptical attitude, which is one of suspense and indifference as opposed to absolute denial. He does not undertake to say whether the gods exist or not. He regards the real essence of Nature as unknowable, on account of the relativity which characterises all sensible impressions. And wherever opinions are divided, he undertakes to provide equally strong arguments for both sides of the question. He also anticipates the two principal tendencies exhibited by all future scepticism in its relation to practice. One is its devotion to humanity, under the double form of exclusive attention to human interests, and great mildness in the treatment of human beings. The other is a disposition to take custom and public opinion, rather than any physical or metaphysical law, for the standard and sanction of morality. Such scepticism might for the moment be hostile to religion; but a reconciliation was likely to be soon effected between them.

The famous theses of Gorgias were quoted in a former chapter as an illustration of the tactics pursued by Greek Humanism in its controversy with physical science. They must be noticed again in the present connexion, on account of their bearing on the development of scepticism, and as having inaugurated a method of reasoning often employed in subsequent attacks, directed, not against the whole of knowledge, but against particular parts of it. The scepticism of Protagoras rested on the assumption that there is an external reality from the reaction of which with mind all our perceptions proceed. Neither of these two factors can be known apart from the other, and as both are in a constant flux, our knowledge of the resulting compound at one time does not show what it has been or will be at another time. But Gorgias altogether denied the existence of any objective reality; and he attempted to disprove it by an analytical instead of a synthetic argument, laying down a series of disjunctive propositions, and upsetting the different alternatives in succession. Existence must be either something or nothing, or both together; and if something, it must be either finite or infinite, or both, and either one or many, or both. His argument against an infinite existence is altogether futile; but it serves to illustrate the undeveloped state of reflection at that period. The eternity of the world is confounded with its unlimited extension in space: and this hypothesis, again, is met by the transparent quibble that the world, not being in any one place, must be nowhere or not at all. And the alternative that the world has not always existed is refuted by the unproved assumption, which, apparently, no Greek philosopher ever thought of disputing, that nothing can begin without being caused by something else. Still, however contemptible such reasonings may seem, it is obvious that in them we have the first crude form of the famous antinomies by which Kant long afterwards sought to prove the impossibility of a world existing in space and time apart from a percipient subject, and which have since been used to establish in a more general way the unknowability of existence as such. It will also be observed that the sceptical arguments respectively derived from the relativity of thought and from the contradictions inherent in its ultimate products are run together by modern agnostics. But no reason that we can remember has ever been given to show that an idea is necessarily subjective because it is self-contradictory.

The second thesis of Gorgias was that, even granting the world to exist, it could not possibly be known. Here the reasoning is unexpectedly weak. Because all thoughts do not represent facts,—as, for example, our ideas of impossible combinations, like chariots running over the sea,—it is assumed that none do. But the problem how to distinguish between true and false ideas was raised, and it was round this that the fiercest battle between dogmatists and sceptics subsequently raged. And in the complete convertibility of consciousness and reality postulated by Gorgias, we may find the suggestion of a point sometimes overlooked in the automatist controversy—namely, that the impossibility, if any, of our acting on the material world reciprocally involves the impossibility of its acting on us, in so far as we are conscious beings. If thought cannot be translated into movement, neither can movement be translated into thought.

The third thesis maintains that, granting the world to exist and to be knowable, one man cannot communicate his knowledge to another; for, the different classes of sensations being heterogeneous, a visual or tactual impression on our consciousness cannot be conveyed by an auditory impression on the consciousness of someone else. This difficulty has been completely overcome by the subsequent progress of thought. We cannot, it is true, directly communicate more than a few sensations to one another; but by producing one we may call up others with which it has become associated through previous experience. And the great bulk of our knowledge has been analysed into relations of co-existence, succession, and resemblance, which are quite independent of the particular symbols employed to transmit them from one mind to another.220

The scepticism of Aristippus and the Cyrenaics mediated between the views of Protagoras and those of Gorgias, while marking an advance on both. According to this school, we know nothing beyond our own feelings, and it must be left undecided whether they are caused by an external reality or not. Nor can the feelings of one individual justify us in reasoning to the existence of similar feelings in the mind of another individual.221 It might be objected that the arguments advanced in support of the latter assertion are suicidal, for they are derived from the abnormal states of consciousness accompanying particular diseases, or else from the divergences of taste exhibited by different individuals even when in good health,—an apparent admission that we are sufficiently well acquainted with the phenomena in question to institute a comparison between them, which, by hypothesis, is impossible. And this is, in fact, the method by which Mr. Herbert Spencer has endeavoured to upset the whole theory of subjective idealism, as involving at every step an assumption of the very realities that it professes to deny. But the Cyrenaic and the modern idealist have a perfect right to show that the assumptions of their adversaries are self-contradictory; and the readiest way of so doing is to reason from them as if they were true. The real answer to that extreme form of idealism which denies the possibility of making known our feelings to each other is that, our bodies being similarly constructed and responding to similar impressions by similar manifestations, I have the same sort of warrant for assuming that your states of consciousness are like mine that I have for assuming you to exist at all. The inference must, of course, be surrounded by proper precautions, such as are seldom used by unscientific reasoners. We must make sure that the structure is the same and that the excitement is the same, or that their differences, if any, are insignificant, before we can attribute the same value to the same manifestations of feeling on the part of different persons; but that this can be done, at least in the case of the elementary sensations, is shown by the easy detection of such anomalies as colour-blindness where they exist.

With Socrates and Plato, scepticism exhibits itself under two new aspects: as an accompaniment of religious belief, and as an element of constructive thought. Thus they represent both the good and the bad side of this tendency: the aspect under which it is a help, and the aspect under which it is a hindrance to scientific investigation. With both philosophers, however, the restriction or negation of human knowledge was a consequence rather than a cause of their theological convictions; nor do they seem to have appreciated its value as a weapon in the controversy with religious unbelief. When Socrates represented the irreconcilable divergence in the explanations of Nature offered by previous thinkers as a sufficient condemnation of their several pretensions, he did not set this fact against the arguments by which a Xenophanes had similarly endeavoured to overthrow the popular mythology; but he looked on it as a fatal consequence of their insane presumption in meddling with the secrets of the gods. On one occasion only, when explaining to EuthydÊmus that the invisibility of the gods is no reason for doubting their existence, he argues, somewhat in Butler’s style, that our own minds, whose existence we cannot doubt, are equally invisible.222 And the Platonic Socrates makes it his business to demonstrate the universality of human ignorance, not as a caution against dogmatic unbelief, but as a glorification of the divine knowledge; though how we come to know that there is any such knowledge he leaves utterly unexplained.

In Plato’s Parmenides we have to note the germ of a new dialectic. There it is suggested that we may overcome the difficulties attending a particular theory—in this instance the theory of self-existing ideas—by considering how much greater are the difficulties which would ensue on its rejection. The arguments advanced by Zeno the Eleatic against the reality of motion are mentioned as a case in point; and Plato proceeds to illustrate his proposed method by showing what consequences respectively follow if we first assume the existence, and then the non-existence of the One; but the whole analysis seems valueless for its immediate purpose, since the resulting impossibilities on either side are left exactly balanced; and Plato does not, like some modern metaphysicians, call in our affections to decide the controversy.

The method by which Plato eventually found his way out of the sceptical difficulty, was to transform it from a subjective law of thought into an objective law of things. Adopting the Heracleitean physics as a sufficient explanation of the material world, he conceived, at a comparatively early period of his mental evolution, that the fallaciousness of sense-impressions is due, not to the senses themselves, but to the instability of the phenomena with which they deal; and afterwards, on discovering that the interpretation of ideal relations was subject to similar perplexities, he assumed that, in their case also, the contradiction arises from a combination of Being with not-Being determining whatever differences prevail among the ultimate elements of things. And, finally, like Empedocles, he solved the problem of cognition by establishing a parallel between the human soul and the universe as a whole; the circles of the Same and the Other being united in the celestial orbits and also in the mechanism of the brain.223

It was by an analogous, though, of course, far more complicated and ingenious adjustment, that Hegel sought to overcome the agnosticism which Kant professed to have founded on a basis of irrefragable proof. With both philosophers, however, the sceptical principle was celebrating its supreme triumph at the moment of its fancied overthrow. The dogmatism of doubt could go no further than to resolve the whole chain of existence into a succession of mutually contradictory ideas.

If the synthesis of affirmation and negation cannot profitably be used to explain the origin of things in themselves, it has a real and very important function when limited to the subjective sphere, to the philosophy of practice and of belief. It was so employed by Socrates, and, on a much greater scale, by Plato himself. To consider every proposition from opposite points of view, and to challenge the claim of every existing custom on our respect, was a proceeding first instituted by the master, and carried out by the disciple in a manner which has made his investigations a model for every future enquirer. Something of their spirit was inherited by Aristotle; but, except in his logical treatises, it was overborne by the demands of a pre-eminently dogmatic and systematising genius. In criticising the theories of his predecessors, he has abundantly illustrated the power of dialectic, and he has enumerated its resources with conscientious completeness; but he has not verified his own conclusions by subjecting them to this formidable testing apparatus.

Meanwhile the scepticism of Protagoras had not been entirely absorbed into the systems of his rivals, but continued to exist as an independent tradition, or in association with a simpler philosophy. The famous school of Megara, about which, unfortunately, we have received very little direct information, was nominally a development of the Socratic teaching on its logical side, as the Cynic and Cyrenaic schools were on its ethical side, but like them also, it seems to have a more real connexion with the great impulse previously given to speculation by the Sophists. At any rate, we chiefly hear of the Megarians as having denied the possibility of definition, to which Socrates attached so much importance, and as framing questions not susceptible of a categorical answer,—an evident satire on the Socratic method of eliciting the truth by cross-examination.224 What they really derived from Socrates seems to have been his mental concentration and independence of external circumstances. Here they closely resembled the Cynics, as also in their contempt for formal logic; but while Antisthenes found a sanction for his indifference and impassivity in the order of nature, their chief representative, Stilpo, achieved the same result by pushing the sceptical principle to consequences from which even the Cyrenaics would have shrunk. Denying the possibility of attaching a predicate to a subject, he seems, in like manner, to have isolated the mind from what are called its affections, or, at least, to have made this isolation his ideal of the good. Even the Stoics did not go to such a length; and Seneca distinguishes himself from the followers of Stilpo by saying, ‘Our sage feels trouble while he overcomes it, whereas theirs does not feel it at all.’225

IV.

So far, the sceptical theory had been put forward after a somewhat fragmentary fashion, and in strict dependence on the previous development of dogmatic philosophy. With the Humanists it had taken the form of an attack on physical science; with the Megarians, of a criticism on the Socratic dialectic; with both, it had been pushed to the length of an absolute negation, logically not more defensible than the affirmations to which it was opposed. What remained was that, after being consistently formulated, its results should be exhibited in their systematic bearing on the practical interests of mankind. The twofold task was accomplished by Pyrrho, whose name has accordingly continued to be associated, even in modern times, with the profession of universal doubt. This remarkable man was a native of Elis, where a branch of the Megarian school had at one time established itself; and it seems likely that the determining impulse of his life was, directly or indirectly, derived from Stilpo’s teaching. A contemporary of Alexander the Great, he accompanied the Macedonian army on its march to India, subsequently returning to his native city, where he died at an advanced age, about 275 B.C. The absurd stories about his indifference to material obstacles when out walking have been already mentioned in a former chapter, and are sufficiently refuted by the circumstances just related. The citizens of Elis are said to have shown their respect for the philosopher by exempting him from taxation, appointing him their chief priest—no inappropriate office for a sceptic of the true type—and honouring his memory with a statue, which was still pointed out to sightseers in the time of Pausanias.226

Pyrrho, who probably no more believed in books than in anything else, never committed his opinions to writing; and what we know of them is derived from the reports of his disciples, which, again, are only preserved in a very incomplete form by the compilers of the empire. According to these, Pyrrho began by declaring that the philosophic problem might be summed up in the three following questions: ‘What is the nature of things? What should be our relation to them? What is the practical consequence of this determination?’ Of its kind, this statement is probably the best ever framed, and might be accepted with equal readiness by every school of thought. But the scepticism of Pyrrho at once reveals itself in his answer to the first question. We know nothing about things in themselves. Every assertion made respecting them is liable to be contradicted, and neither of the two opposing propositions deserves more credence than the other. The considerations by which Pyrrho attempts to establish this proposition were probably suggested by the systems of Plato and Aristotle. The only possible avenues of communication with the external world are, he tells us, sense and reason. Of these the former was so universally discredited that he seems to have regarded any elaborate refutation of its claims as superfluous. What we perceive by our senses is the appearance, not the reality of things. This is exactly what the Cyrenaics had already maintained. The inadequacy of reason is proved by a more original method. Had men any settled principles of judgment, they would agree on questions of conduct, for it is with regard to these that they are best informed, whereas the great variety of laws and customs shows that the exact opposite is true. They are more hopelessly divided on points of morality than on any other.227 It will be remembered that Pyrrho’s fellow-townsman, Hippias, had, about a hundred years earlier, founded his theory of Natural Law on the arbitrary and variable character of custom. The result of combining his principles with those professed by Protagoras and Gorgias was to establish complete moral scepticism; but it would be a mistake to suppose that moral distinctions had no value for him personally, or that they were neglected in his public teaching.

Timon, a celebrated disciple of Pyrrho, added another and, from the speculative point of view, a much more powerful argument, which, however, may equally have been borrowed from the master’s lectures. Readers of the Posterior Analytics will remember how strongly Aristotle dwells on the necessity of starting with first principles which are self-evidently true. The chain of demonstration must have something to hang on, it cannot be carried back ad infinitum. Now, Timon would not admit of such a thing as first principles. Every assumption, he says, must rest on some previous assumption, and as this process cannot be continued for ever, there can be no demonstration at all. This became a very favourite weapon with the later Sceptics, and, still at the suggestion of Aristotle, they added the further ‘trope’ of compelling their adversaries to choose between going back ad infinitum and reasoning in a circle—in other words, proving the premises by means of the conclusion. Modern science would not feel much appalled by the sceptical dilemma. Its actual first principles are only provisionally assumed as ultimate, and it is impossible for us to tell how much farther their analysis may be pursued; while, again, their validity is guaranteed by the circular process of showing that the consequences deduced from them agree with the facts of experience. But as against those modern philosophers who, in adherence to the Aristotelian tradition, still seek to base their systems on first principles independent of any individual experience, the sceptical argument is unanswerable, and has even been strengthened by the progress of knowledge. To this day, thinkers of different schools cannot agree about the foundations of belief, and what to one seems self-evidently true, is to another either conceivably or actually false. To Mr. Herbert Spencer the persistence of force is a necessary truth; to Prof. Stanley Jevons its creation is a perfectly possible contingency; while to others, again, the whole conception of force, as understood by Mr. Spencer, is so absolutely unmeaning that they would decline to entertain any proposition about the invariability of the objective reality which it is supposed to represent. And when the À priori dogmatist affects to treat the negations of his opponents as something that they do not think, but only think they think, they may, with perfect fairness, attribute his rejection of their beliefs—as, for example, free-will—to a similar subjective illusion. Moreover, the pure experimentalists can point to a circumstance not foreseen by the ancient sceptics, which is that propositions once generally regarded as incontrovertible by thinking men, are now as generally abandoned by them.

Having proved, to his satisfaction, that the nature of things is unknowable, Pyrrho proceeds to deal with the two remaining heads of the philosophic problem. To the question what should be our relation to a universe which we cannot reach, the answer is, naturally, one of total indifference. And the advantage to be derived from this attitude is, he tells us, that we shall secure the complete imperturbability wherein true happiness consists. The sceptical philosophy does not agree with Stilpo in denying the reality of actual and immediate annoyances, for it denies nothing; but it professes to dispel that very large amount of unhappiness which arises from the pursuit of fancied goods and the expectation of future calamities. In respect to the latter, what Pyrrho sought was to arrive by the exercise of reasoning at the tranquillity which unreasoning animals naturally enjoy. Thus, we are told that, when out at sea in a storm, he called the attention of the terrified passengers to a little pig which was quietly feeding in spite of the danger, and taught them that the wise man should attain to a similar kind of composure.

Various other anecdotes of more or less doubtful authenticity are related, showing that the philosopher could generally, though not always, act up to his own ideal of indifference. He lived with his sister, who was a midwife by profession, and patiently submitted to the household drudgery which she unsparingly imposed on him. Once, however, she succeeded in goading him into a passion; and on being rather inopportunely reminded of his professed principles by a bystander, the sceptic tartly replied that a wretched woman like that was no fit subject for a display of philosophical indifference. On another occasion, when taunted for losing his self-possession at the attack of a furious dog, he observed, with truth, that, after all, philosophers are human beings.228

Thus we find Pyrrho competing with the dogmatists as a practical moralist, and offering to secure the inward tranquillity at which they too aimed by an easier method than theirs. The last eminent representative of the sceptical school, Sextus Empiricus, illustrates its pretensions in this respect by the well-known story of Apelles, who, after vainly endeavouring to paint the foam on a horse’s mouth, took the sponge which he used to wipe his easel, and threw it at the picture in vexation. The mixture of colours thus accidentally applied produced the exact effect which he desired, but at which no calculation could arrive. In like manner, says Sextus, the confusion of universal doubt accidentally resulted in the imperturbability which accompanies suspense of judgment as surely as a body is followed by its shadow.229 There was, however, no accident about the matter at all. The abandonment of those studies which related to the external world was a consequence of the ever-increasing attention paid to human interests, and that these could be best consulted by complete detachment from outward circumstances, was a conclusion inevitably suggested by the negative or antithetical moment of Greek thought. Hence, while the individualistic and apathetic tendencies of the age were shared by every philosophical school, they had a closer logical connexion with the idealistic than with the naturalistic method; and so it is among the successors of Protagoras that we find them developed with the greatest distinctness; while their incorporation with Stoicism imposed a self-contradictory strain on that system which it never succeeded in shaking off. Epicureanism occupied a position midway between the two extremes; and from this point of view, we shall be better able to understand both its inherent weakness as compared with the other ancient philosophies, and the admiration which it has attracted from opposite quarters in recent years. To some it is most interesting as a revelation of law in Nature, to others as a message of deliverance to man—not merely a deliverance from ignorance and passion, such as its rivals had promised, but from all established systems, whether religious, political, or scientific. And unquestionably Epicurus did endeavour to combine both points of view in his theory of life. In seeking to base morality on a knowledge of natural law he resembles the Stoics. In his attacks on fatalism, in his refusal to be bound down by a rigorously scientific explanation of phenomena, in his failure to recognise the unity and power of Nature, and in his preference of sense to reason, he partially reproduces the negative side of Scepticism; in his identification of happiness with the tranquil and imperturbable self-possession of mind, in his mild humanism, and in his compliance with the established religion of the land, he entirely reproduces its positive ethical teaching. On the other hand, the two sides of his philosophy, so far from completing, interfere with and mar one another. Emancipation from the outward world would have been far more effectually obtained by a total rejection of physical science than by the construction of a theory whose details were, on any scientific principles, demonstrably untrue. The appeal to natural instinct as an argument for hedonism would, consistently followed out, have led to one of two conclusions, either of which is incompatible with the principle that imperturbability is the highest good. If natural instinct, as manifested by brutes, by children, and by savages, be the one sure guide of action, then Callicles was right, and the habitual indulgence of passion is wiser than its systematic restraint. But if Nature is to be studied on a more specific and discriminating plan, if there are human as distinguished from merely animal impulses, and if the higher development of these should be our rule of life, then Plato and Aristotle and the Stoics were right, and the rational faculties should be cultivated for their own sake, not because of the immunity from superstitious terrors which they secure. And we may add that the attendance on public worship practised by Epicurus agreed much better with the sceptical suspense of judgment touching divine providence than with its absolute negation, whether accompanied or not by a belief in gods who are indifferent to sacrifice and prayer.

It was, no doubt, for these and similar reasons that all the most vigorous intellects of Hellas ranged themselves either on the Stoic or on the Sceptic side, leaving the halfhearted compromise of Epicurus to those who could not think out any one theory consistently, or who, like the Romans at first, were not acquainted with any system but his. Henceforth, during a period of some centuries, the whole philosophic movement is determined by the interaction of these two fundamental forces. The first effect of their conflict was to impose on Scepticism an important modification, illustrating its essentially parasitic character. We have seen it, as a general tendency of the Greek mind, clinging to the very texture of mythology, accompanying the earliest systematic compilation of facts, aiding the humanistic attacks on physical science, associated with the first great religious reaction, operating as the dialectic of dialectic itself, and finally assuming the form of a shadowy morality, in rivalry with and imitation of ethical systems based on a positive and substantial doctrine. We have now to trace its metamorphosis into a critical system extending its ramifications in parallelism with the immense dogmatic structure of Stoicism, and simultaneously endeavouring to reach the same practical results by a more elastic adaptation to the infirmities of human reason and the uncertainties of sensible experience. As such, we shall also have to study its influence over the most plastic of Roman intellects, the great orator in whose writings Greek philosophy was reclothed with something of its ancient charm, so that many who were debarred from admission to the groves and porticoes of Athens have caught an echo of the high debates which once stirred their recesses, as they trod the shady slopes of Tusculum under his visionary guidance, or followed his searching eyes over the blue waters to Pompeii, while he reasoned on mind and its object, on sense and knowledge, on doubt and certainty, with Lucullus and Hortensius, on the sunlight Baian shore. It is the history of the New Academy that we shall now proceed to trace.

V.

When we last had occasion to speak of the Platonic school, it was represented by Polemo, one of the teachers from whose lessons Zeno the Stoic seems to have compiled his system. Under his superintendence, Platonism had completely abandoned the metaphysical traditions of its founder. Physics and dialectics had already been absorbed by Aristotelianism. Mathematics had passed into the hands of experts. Nothing remained but the theory of ethics; and, as an ethical teacher, Polemo was only distinguished from the Cynics by the elegance and moderation of his tone. Even this narrow standing-ground became untenable when exposed to the formidable competition of Stoicism. The precept, Follow Nature, borrowed by the new philosophy from Polemo, acquired a far deeper significance than he could give it, when viewed in the light of an elaborate physical system showing what Nature was, and whither her guidance led. But stone after stone had been removed from the Platonic superstructure and built into the walls of other edifices, only to bring its original foundation the more prominently into sight. This was the initial doubt of Socrates, widened into the confession of universal ignorance attributed to him by Plato in the Apologia. Only by returning to the exclusively critical attitude with which its founder had begun could the Academy hope to exercise any influence on the subsequent course of Greek speculation. And it was also necessary that the agnostic standpoint should be taken much more in earnest by its new representatives than by Socrates or Plato. With them it had been merely the preparation for a dogmatism even more self-confident than that of the masters against whom they fought; but if in their time such a change of front might seem compatible with the retention of their old strongholds, matters now stood on a widely different footing. Experience had shown that the purely critical position could not be abandoned without falling back on some one or other of the old philosophies, or advancing pretensions inconsistent with the dialectic which had been illustrated by their overthrow. The course marked out for Plato’s successors by the necessities of thought might have been less evident had not Pyrrhonism suddenly revealed to them where their opportunities lay, and at the same time, by its extinction as an independent school, allowed them to step into the vacant place.

It was at this juncture that the voluntary withdrawal of an older fellow-pupil placed Arcesilaus at the head of the Academy. The date of his accession is not given, but we are told that he died 241 or 240 B.C. in the seventy-fifth year of his age. He must, therefore, have flourished a generation later than Zeno and Epicurus. Accomplished, witty, and generous, his life is described by some as considerably less austere than that of the excellent nonentities whom he succeeded. Yet its general goodness was testified to by no less an authority than his contemporary, the noble Stoic, Cleanthes. ‘Do not blame Arcesilaus,’ exclaimed the latter to an unfriendly critic; ‘if he denies duty in his words, he affirms it in his deeds.’ ‘You don’t flatter me,‘ observed Arcesilaus. ‘It is flattering you,’ rejoined Cleanthes, ‘to say that your actions belie your words.’230 It might be inferred from this anecdote that the scepticism of the new teacher, like that of Carneades after him, was occasionally exercised on moral distinctions, which, as then defined and deduced, were assuredly open to very serious criticism. Even so, in following the conventional standard of the age, he would have been acting in perfect consistency with the principles of his school. But, as a matter of fact, his attacks seem to have been exclusively aimed at the Stoic criterion of certainty. We have touched on this difficult subject in a former chapter, but the present seems a more favourable opportunity for setting it forth in proper detail.

The Stoics held, as Mr. Herbert Spencer, who resembles them in so many respects, now holds, that all knowledge is ultimately produced by the action of the object on the subject. Being convinced, however, that each single perception, as such, is fallible, they sought for the criterion of certainty in the repetition and combination of individual impressions; and, again like Mr. Spencer, but also in complete accordance with their dynamic theory of Nature, they estimated the validity of a belief by the degree of tenacity with which it is held. The various stages of assurance were carefully distinguished and arranged in an ascending series. First came simple perception, then simple assent, thirdly, comprehension, and finally demonstrative science. These mental acts were respectively typified by extending the forefinger, by bending it as in the gesture of beckoning, by clenching the fist, and by placing it, thus clenched, in the grasp of the other hand. From another point of view, they defined a true conviction as that which can only be produced by the action of a corresponding real object on the mind. This theory was complicated still further by the Stoic interpretation of judgment as a voluntary act; by the ethical significance which it consequently received; and by the concentration of all wisdom in the person of an ideal sage. The unreserved bestowal of belief is a practical postulate dictated by the necessities of life; but only he who knows what those necessities are, in other words only the wise man, knows when the postulate is to be enforced. In short, the criterion of your being right is your conviction that you are right, and this conviction, if you really possess it, is a sufficient witness to its own veracity. Or again, it is the nature of man to act rightly, and he cannot do so unless he has right beliefs, confirmed and clinched by the consciousness that they are right.

Arcesilaus left no writings, and his criticisms on the Stoic theory, as reported by Cicero and Sextus Empiricus, have a somewhat unsatisfactory appearance. By what we can make out, he seems to have insisted on the infallibility of the wise man to a much greater extent than the Stoics themselves, not allowing that there was any class of judgments in which he was liable to be mistaken. But just as the Stoics were obliged to accept suicide as an indispensable safeguard for the inviolability of their personal dignity and happiness, so also Arcesilaus had recourse to a kind of intellectual suicide for the purpose of securing immunity from error. The only way, according to him, in which the sage can make sure of never being mistaken is never to be certain about anything. For, granting that every mental representation is produced by a corresponding object in the external world, still different objects are connected by such a number of insensible gradations that the impressions produced by them are virtually indistinguishable from one another; while a fertile source of illusions also exists in the diversity of impressions produced by the same object acting on different senses and at different times. Moreover, the Stoics themselves admitted that the sage might form a mistaken opinion; it was only for his convictions that they claimed unerring accuracy, each of the two—opinion and conviction—being the product of a distinct intellectual energy. Here again, Arcesilaus employed his method of infinitesimal transitions, refusing to admit that the various cognitive faculties could be separated by any hard and fast line; especially as, according to the theory then held by all parties, and by none more strongly than the Stoics, intellectual conceptions are derived exclusively from the data of sense and imagination. We can see that the logic of Scepticism is, equally with that of the other Greek systems, determined by the three fundamental moments of Greek thought. There is first the careful circumscription of certainty; then there is the mediating process by which it is insensibly connected with error; and, lastly, as a result of this process, there is the antithetical opposition of a negative to an affirmative proposition on every possible subject of mental representation.231

To the objection that his suspensive attitude would render action impossible, Arcesilaus replied that any mental representation was sufficient to set the will in motion; and that, in choosing between different courses, probability was the most rational means of determination. But the task of reducing probable evidence to a system was reserved for a still abler dialectician, who did not appear on the scene until a century after his time. Arcesilaus is commonly called the founder of the Middle, Carneades the founder of the New Academy. The distinction is, however, purely nominal. Carneades founded nothing. His principles were identical with those of his predecessor; and his claim to be considered the greatest of the Greek sceptics is due to his having given those principles a wider application and a more systematic development. The Stoics regarded it as a special dispensation of providence that Chrysippus, the organising genius of their school, should have come between its two most formidable opponents, being thus placed in a position to answer the objections of the one and to refute by anticipation those of the other.232 It might seem to less prejudiced observers that the thinker whose cause benefited most by this arrangement was Carneades. Parodying a well-known iambic, he used to say:

‘Without Chrysippus I should not have been.’233

And, in fact, it was by a close study of that writer’s voluminous treatises that he was able to cover the immense extent of ground which Scepticism thenceforward disputed with the dogmatic schools. Nor were his attacks directed against Stoicism only, but against all other positive systems past and present as well. What he says about the supposed foundation of knowledge is even now an unanswerable objection to the transcendental realism of Mr Herbert Spencer. States of consciousness speak for themselves alone, they do not include the consciousness of an external cause.234 But the grounds on which he rests his negation of all certainty are still superficial enough, being merely those sensible illusions which the modern science of observation has been able either to eliminate altogether or to restrict within narrow and definable limits. That phenomena, so far from being necessarily referred to a cause which is not phenomenal, cannot be thought of at all except in relation to one another, and that knowledge means nothing more than a consciousness of this relation, was hardly perceived before the time of Hume.

Turning from sense to reason, Carneades attacks the syllogistic process on grounds already specified in connexion with the earlier Sceptics; and also on the plea that to prove the possibility of syllogism is itself to syllogise, and thus involves either a petitio principii or a regress ad infinitum.235 Such a method is, of course, suicidal, for it disproves the possibility of the alleged disproof, a consideration which the Stoics did not fail to urge, and which the later Sceptics could only meet by extending the rule of suspense to their own arguments against argument.236 Nevertheless the sceptical analysis detected some difficulties in the ordinary theory of logic, which have been revived in modern times, and have not yet received any satisfactory solution. Sextus Empiricus, probably copying an earlier authority, it may be Carneades himself, observes that, as the major premise of every syllogism virtually contains the minor, it is either superfluous, or assumes the proposition to be proved. Thus we argue that Socrates is an animal because he is a man, and all men are animals. But if we do not know this latter proposition to be true in the case of Socrates, we cannot be sure that it is true in any case; while if we know it to be true in his case, we do not need to begin by stating it in general terms. And he also attempts to show the impossibility of a valid induction by the consideration, since so often urged, that to generalise from a limited number of instances to a whole class is unsafe, for some of the unknown instances may be contradictory, while the infinite, or at least indefinite multiplicity of individuals precludes the possibility of their exhaustive enumeration.237

When the Academicians pass from the form to the matter of dogmatic philosophy, their criticisms acquire greater interest and greater weight. On this ground, their assaults are principally directed against the theology of their Stoic and Epicurean rivals. It is here in particular that Carneades reveals himself to us as the Hume of antiquity. Never has the case for agnosticism been more powerfully made out than by him or by the disciples whom he inspired. To the argument for the existence of supernatural beings derived from universal consent, he replies, first, that the opinion of the vulgar is worthless, and secondly, that men’s beliefs about the gods are hopelessly at variance with one another, even the same divinity being made the subject of numberless discordant legends.238 He reduces the polytheistic deification of natural objects to an absurdity by forcing it back through a series of insensible gradations into absolute fetichism.239 The personification of mental qualities is similarly treated, until an hypothesis is provided for every passing mood.240 Then, turning to the more philosophical deism of the Stoics, he assails their theory of the divine benevolence with instance after instance of the apparent malevolence and iniquity to be found in Nature; vividly reminding one of the facts adduced by Mr. Herbert Spencer in confutation of the similar views held by modern English theologians.241 As against the whole theory of final causes, Carneades argues after a method which, though logically sound, could not then present itself with the authority which advancing science has more recently shown it to possess. ‘What you Stoics,’ he says, ‘explain as the result of conscious purpose, other philosophers, like Strato for instance, explain with equal plausibility as the result of natural causation. And such is our ignorance of the forces at work in Nature that even where no mechanical cause can be assigned, it would be presumptuous to maintain that none can exist.242 The reign of law does not necessarily prove the presence of intelligence; it is merely the evidence of a uniform movement quite consistent with all that we know about the working of unconscious forces.243 To contend, with Socrates, that the human mind must be derived from a Universal Mind pervading all Nature would logically involve the transfer of every human attribute to its original source.244 And to say that the Supreme Being, because it surpasses man, must possess an intelligence like his, is no more rational than to make the same assumption with regard to a great city because it is superior to an ant.’245

The materialism of his dogmatic contemporaries placed them at a terrible disadvantage when the sceptical successor of Plato went on to show that eternal duration is incompatible with whatever we know about the constitution of corporeal substance; and this part of his argument applied as much to the Epicurean as to the Stoic religion.246 But even a spiritualistic monotheism is not safe from his dissolving criticism. According to Carneades, a god without senses has no experience of whatever pleasurable or painful feelings accompany sensation, and is therefore, to that extent, more ignorant than a man; while to suppose that he experiences painful sensations is the same as making him obnoxious to the diminished vitality and eventual death with which they are naturally associated. And, generally speaking, all sensation involves a modification of the sentient subject by an external object, a condition necessarily implying the destructibility of the former by the latter.247 So also, moral goodness is an essentially relative quality, inconceivable without the possibility of succumbing to temptation, which we cannot attribute to a perfect Being.248 In a word, whatever belongs to conscious life being relative and conditioned, personality is excluded from the absolute by its very definition.

As to the proofs of divine agency derived from divination, they are both irrational and weak. If all things are predetermined by God’s providence, knowledge of the future is useless, and, therefore, cannot have been given to us. Moreover, no confidence can be placed in the alleged fulfilments of prophecy; probably most of them are fictitious and the remainder accidental. For the rest, good luck is distributed without regard to merit; and the general corruption of mankind shows that, from the Stoic point of view, human nature is a complete failure.249

Well may M. Havet say of the Academicians: ‘ce sont eux et non les partisans d’Epicure qui sont les libres penseurs de l’antiquitÉ ou qui l’auraient voulu Être; mais ils ne le pouvaient pas.’250 They could not, for their principles were as inconsistent with an absolute negation as with an absolute affirmation; while in practice their rule was, as we have said, conformity to the custom of the country; the consequence of which was that Sceptics and Epicureans were equally assiduous in their attendance at public worship. It is, therefore, with perfect dramatic appropriateness that Cicero puts the arguments of Carneades into the mouth of Cotta, the Pontifex Maximus; and, although himself an augur, takes the negative side in a discussion on divination with his brother Quintus. And our other great authority on the sceptical side, Sextus Empiricus, is not less emphatic than Cotta in protesting his devotion to the traditional religion of the land.251

We have seen with what freedom Carneades discussed the foundations of morality. It is now evident that in so doing he did not exceed the legitimate functions of criticism. No one at the present day looks on Prof. Bain and Mr. Henry Sidgwick as dangerous teachers because they have made it clear that to pursue the greatest happiness of the greatest number is not always the way to secure a maximum of happiness for oneself. The really dangerous method, as we now see, is to foster illusions in early life which subsequent experience must dispel.

With the introduction of practical questions, we pass to the great positive achievement of Carneades, his theory of probable evidence. Intended as an account of the process by which belief is adjusted to safe action rather than of the process by which it is brought into agreement with reality, his logic is a systematisation of the principles by which prudent men are unconsciously guided in common life. Carneades distinguishes three degrees of probability. The lowest is attached to simple perception. This arises when we receive the impression of an object without taking the attendant circumstances into account. The next step is reached when our first impression is confirmed by the similar impressions received from its attendant circumstances; and when each of these, again, bears the test of a similar examination our assurance is complete. The first belief is simply probable; the second is probable and uncontradicted; the third probable, uncontradicted, and methodically established. The example given by Sextus is that of a person who on seeing a coil of rope in a dark passage thinks that it may be a snake, and jumps over it, but on turning round and observing that it remains motionless feels inclined to form a different opinion. Remembering, however, that snakes are sometimes congealed by cold in winter, he touches the coil with his stick, and finally satisfies himself by means of this test that the image present to his mind does not really represent a snake. The circumstances to be examined before arriving at a definite judgment include such considerations as whether our senses are in a healthy condition, whether we are wide awake, whether the air is clear, whether the object is steady, and whether we have taken time enough to be sure that the conditions here specified are fulfilled. Each degree of probability is, again, divisible into several gradations according to the strength of the impressions received and the greater or less consilience of all the circumstances involved.252

The Academic theory of probability bears some resemblance to the Canonic of Epicurus, and may have been partially suggested by it. Both are distinguished from the Aristotelian and Stoic logic by the care with which they provide for the absence of contradictory evidence. In this point, however, the superiority of Carneades to Epicurus is very marked. It is not enough for him that a present impression should suggest a belief not inconsistent with past experience; in the true inductive spirit, he expressly searches for negative instances, and recommends the employment of experiment for this purpose. Still more philosophical is the careful and repeated analysis of attendant circumstances, a precaution not paralleled by anything in the slovenly method of his predecessor. Here the great value of scepticism as an element in mental training becomes at once apparent. The extreme fallibility of the intellectus sibi permissus had to be established before precautions could be adopted for its restraint. But the evidence accepted in proof of this fallibility has been very different at different times, and has itself given rise to more than one fallacious interpretation. With us it is, for the most part, furnished by experience. The circumstance that many demonstrable errors were formerly received as truths is quite sufficient to put us on our guard against untested opinions. With Bacon, it was not the erroneousness of previous systems, but their barrenness and immobility, which led him to question the soundness of their logic; and his doubts were confirmed by an analysis of the disturbing influences under which men’s judgments are formed. The ancient Sceptics were governed entirely by À priori considerations. Finding themselves confronted by an immense mass of contradictory opinions, they argued that some of these must be false as all could not possibly be true. And an analysis of the human faculties led them, equally on À priori grounds, to the conclusion that these irreconcilable divergences were but the result and the reproduction of an interminable conflict carried on within the mind itself. They could not foresee how much time would do towards reducing the disagreement of educated opinion within a narrower compass. They did not know what the experience of experience itself would teach. And their criticisms on the logic and metaphysics of their opponents were rendered inconclusive, as against all certainty, by the extent to which they shared that logic and metaphysics themselves. Carneades, at least, seems to assume throughout that all existence is material, that there is a sharp distinction between subject and object in knowledge, and that there is an equally sharp distinction between sensation and reasoning in the processes by which knowledge is obtained. In like manner, his ethical scepticism all turns on the axiom, also shared by him with the Stoics, that for a man to be actuated by any motive but his own interest is mere folly.

Modern agnosticism occupies the same position with regard to the present foundation and possible future extension of human knowledge as was occupied by the ancient Sceptics with regard to the possibility of all knowledge. Its conclusions also are based on a very insufficient experience of what can be effected by experience, and on an analysis of cognition largely adopted from the system which it seeks to overthrow. Like Scepticism also, when logically thought out, it tends to issue in a self-contradiction, at one time affirming the consciousness of what is, by definition, beyond consciousness; and at another time dogmatically determining the points on which we must remain for ever ignorant. It may be that some problems, as stated by modern thinkers, are insoluble; but perhaps we may find our way our of them by transforming the question to be solved.

If, in the domain of pure speculation, contemporary agnosticism exaggerates the existing divergences, in ethics its whole effort is, contrariwise, to reduce and reconcile them. Such was also the tendency of Carneades. He declared that, in their controversy about the highest good, the difference between the Stoics and the Peripatetics was purely verbal. Both held that we are naturally framed for the pursuit of certain objects, and that virtuous living is the only means by which they can be attained. But while the disciples of Aristotle held that the satisfaction of our natural impulses remains from first to last the only end, the disciples of Zeno insisted that at some point—not, as would seem very particularly specified—virtuous conduct, which was originally the means towards this satisfaction, becomes substituted for it as the supreme and ultimate good.253 That the point at issue was more important than it seemed is evident from its reproduction under another form in modern ethical philosophy. For, among ourselves, the controversy between utilitarianism and what, for want of a better name, we must call intuitionism, is gradually narrowing itself to the question whether the pursuit of another’s good has or has not a higher value than the quantity of pleasure which accrues to him from it, plus the effects of a good example and the benefits that society at large is likely to gain from the strength which exercise gives to the altruistic dispositions of one of its members. Those who attribute an absolute value to altruism, as such, connect this value in some way or other with the spiritual welfare of the agent; and they hold that without such a gain to himself he would gradually fall back on a life of calculating selfishness or of unregulated impulse. Here we have the return from a social to an individual morality. The Stoics, conversely, were feeling their way from the good of the individual to that of the community; and they could only bridge the chasm by converting what had originally been a means towards self-preservation into an end in itself. This Carneades could not see. Convinced that happiness was both necessary and attainable, but convinced also that the systems which had hitherto offered it as their reward were logically untenable, he wished to place morality on the broad basis of what was held in common by all schools, and this seemed to be the rule of obedience to Nature’s dictates,—a rule which had also the great merit of bidding men do in the name of philosophy what they already felt inclined to do without any philosophy at all. We are told, indeed, that he would not commit himself to any particular system of ethics; the inference, however, is not that he ignored the necessity of a moral law, but that he wished to extricate it from a compromising alliance with untenable speculative dogmas. Nevertheless his acceptance of Nature as a real entity was a survival of metaphysics; and his morality was, so far as it went, an incipient return to the traditions of the Old Academy.

VI.

We have now reached a point where Greek philosophy seems to have swung back into the position which it occupied three hundred years before, towards the close of the Peloponnesian War. The ground is again divided between naturalists and humanists, the one school offering an encyclopaedic training in physical science and exact philology, the other literary, sceptical, and limiting its attention to the more immediate interests of life; but both agreeing in the supreme importance of conduct, and differing chiefly as to whether its basis should or should not be sought in a knowledge of the external world. Materialism is again in the ascendant, to this extent at least, that no other theory is contemplated by the students of physical science; while the promise of a spiritualistic creed is to be found, if at all, in the school whose scepticism throws it back on the subjective sphere, the invisible and impalpable world of mind. The attitude of philosophy towards religion has, indeed, undergone a marked change; for the Stoic naturalists count themselves among the most strenuous supporters of beliefs and practices which their Sophistic predecessors had contemned, while the humanist criticism is cautiously guarded by at least an external conformity to established usage; but the Platonic doctrine of immortality has disappeared with the dogmatic spiritualism on which it rested; and faith in superior beings tends to dissociate itself from morality, or to become identified with a simple belief in the fixity of natural law.

Whenever naturalism and scepticism have thus stood opposed, the result has been their transformation or absorption into a new philosophy, combining the systematic formalism of the one with the introspective idealism of the other. In Greece such a revolution had already been effected once before by Plato; and a restoration of his system seemed the most obvious solution that could offer itself on the present occasion. Such was, in fact, the solution eventually adopted; what we have to explain is why its adoption was delayed so long. For this various reasons may be offered. To begin with, the speculative languor of the age was unfavourable to the rise of a new school. Greece was almost depopulated by the demands of foreign service; and at Alexandria, where a new centre of Hellenism had been created, its best energies were absorbed by the cultivation of positive science. It was, no doubt, in great part owing to the dearth of ability that ideas which, at an earlier period, would have been immediately taken up and developed, were allowed to remain stationary for a hundred years—the interval separating a Carneades from an Arcesilaus. The regular organisation of philosophical teaching was another hindrance to progress. A certain amount of property was annexed to the headships of the different schools, and served as an endowment, not of research but of contented acquiescence in the received traditions. Moreover, the jealousy with which the professors of rival doctrines would naturally regard one another, was likely to prevent their mutual approximation from going beyond certain not very close limits, and might even lead to a still severer definition of the characteristic tenets which still kept them apart. Another and deeper disturbing force lay in the dissensions which, at a very early stage of its development, had split the spiritualistic philosophy into two opposing tendencies respectively represented by Plato and Aristotle. Any thinker who wandered away from the principles either of Stoicism or of Scepticism was more likely to find himself bewildered by the conflicting claims of these two illustrious masters, than to discern the common ground on which they stood, or to bring them within the grasp of a single reconciling system. Finally, an enormous perturbation in the normal course of speculation was produced by the entrance of Rome on the philosophical scene. But before estimating the influence of this new force, we must follow events to the point at which it first becomes of calculable importance.

We have seen how Carneades, alike in his theory of probability and in his ethical eclecticism, had departed from the extreme sceptical standpoint. His successor, Clitomachus, was content with committing the doctrines of the master to writing. A further step was taken by the next Scholarch, Philo, who is known as the Larissaean, in order to distinguish him from his more celebrated namesake, the Alexandrian Jew. This philosopher asserted that the negations of the New Academy were not to be taken as a profession of absolute scepticism, but merely as a criticism on the untenable pretensions of the Stoa. His own position was that, as a matter of fact, we have some certain knowledge of the external world, but that no logical account can be given of the process by which it is obtained—we can only say that such an assurance has been naturally stamped on our minds.254 This is the theory of intuitions or innate ideas, still held by many persons; and, as such, it marks a return to pure Platonism, having been evidently suggested by the semi-mythological fancies of the Meno and the Phaedrus. With Philo as with those Scotch professors who long afterwards took up substantially the same position, the leading motive was a practical one, the necessity of placing morality on some stronger ground than that of mere probability. Neither he nor his imitators saw that if ethical principles are self-evident, they need no objective support; if they are derivative and contingent, they cannot impart to metaphysics a certainty which they do not independently possess. The return to the old Academic standpoint was completed by a much more vigorous thinker than Philo, his pupil, opponent, and eventual successor, Antiochus. So far from attempting any compromise with the Sceptics, this philosopher openly declared that they had led the school away from its true traditions; and claimed for his own teaching the merit of reproducing the original doctrine of Plato.255 In reality, he was, as Zeller has shown, an eclectic.256 It is by arguments borrowed from Stoicism that he vindicates the certainty of human knowledge. Pushing the practical postulate to its logical conclusion, he maintains, not only that we are in possession of the truth, but also—what Philo had denied—that true beliefs bear on their face the evidence by which they are distinguished from illusions. Admitting that the senses are liable to error, he asserts the possibility of rectifying their mistakes, and of reasoning from a subjective impression to its objective cause. The Sceptical negation of truth he meets with the familiar argument that it is suicidal, for to be convinced that there can be no conviction is a contradiction in terms; while to argue that truth is indistinguishable from falsehood implies an illogical confidence in the validity of logical processes; besides involving the assumption that there are false appearances and that they are known to us as such, which would be impossible unless we were in a position to compare them with the corresponding truths.257 For his own part, Antiochus adopted without alteration the empirical theory of Chrysippus, according to which knowledge is elaborated by reflection out of the materials supplied by sense. His physics were also those of Stoicism with a slight Peripatetic admixture, but without any modification of their purely materialistic character. In ethics he remained truer to the Academic tradition, refusing to follow the Stoics in their absolute isolation of virtue from vice, and of happiness from external circumstances, involving as it did the equality of all transgressions and the worthlessness of worldly goods. But the disciples of the Porch had made such large concessions to common sense by their theories of preference and of progress, that even here there was very little left to distinguish his teaching from theirs.258

Meanwhile a series of Stoic thinkers had also been feeling their way towards a compromise with Plato and Aristotle, which, so far as it went, was a step in the direction of spiritualism. We have seen, in a former chapter, how one of the great distinguishing marks of Stoicism, as compared with the systems immediately preceding it, was the substitution of a pervading monism for their antithesis between God and the world, between heaven and earth, between reason and sense. It will be remembered also that this monistic creed was associated with a return to the Heracleitean theory that the world is periodically destroyed by fire. Now, with reference to three out of these four points, BoÊthus, a Stoic contemporary of Carneades, returned to the Aristotelian doctrine. While still holding to the materialism of his own school, including a belief in the corporeal nature of the divinity, he separated God from the world, and represented him as governing its movements from without; the world itself he maintained to be eternal; and in the mind of man he recognised reason or nous as an independent source of conviction. In his cosmology, BoÊthus was followed by a more celebrated master, Panaetius, who also adopted the Aristotelian rationalism so far as to deny the continued existence of the soul after death, and to repudiate the belief in divination which Stoicism had borrowed from popular superstition; while in psychology he partially restored the distinction between life and mind which had been obliterated by his predecessors.259 The dualistic theory of mind was carried still further by Posidonius, the most eminent Stoic of the first century B.C. This very learned and accomplished master, while returning in other points to a stricter orthodoxy, was led to admit the Platonic distinction between reason and passion, and to make it the basis of his ethical system.260 But the Platonising tendencies of Posidonius had no more power than those of Antiochus to effect a true spiritualistic revival, since neither they nor any of their contemporaries had any genius for metaphysical speculation; while the increased attention paid to Aristotle did not extend to the fundamental principles of his system, which, even within the Peripatetic school, were so misconceived as to be interpreted in a thoroughly materialistic sense.261

A distinct parallelism may be traced in the lines of evolution along which we have accompanied our two opposing schools. While the Academicians were coming over to the Stoic theory of cognition, the Stoics themselves were moving in the same general direction, and seeking for an external reality more in consonance with their notions of certainty than the philosophy of their first teachers could supply. For, as originally constituted, Stoicism included a large element of scepticism, which must often have laid its advocates open to the charge of inconsistency from those who accepted the same principle in a more undiluted form. The Heracleitean flux adopted by Zeno as the physical basis of his system, was much better suited to a sceptical than to a dogmatic philosophy, as the use to which it was put by Protagoras and Plato sufficiently proved; and this was probably the reason why BoÊthus and Panaetius partially discarded it in favour of a more stable cosmology. The dialectical studies of the school also tended to suggest more difficulties than they could remove. The comprehensive systematisation of Chrysippus, like that of Plato and Aristotle, had for its object the illustration of each topic from every point of view, and especially from the negative as well as from the positive side. The consequence was that his indefatigable erudition had collected a great number of logical puzzles which he had either neglected or found himself unable to solve. There would, therefore, be a growing inclination to substitute a literary and rhetorical for a logical training: and as we shall presently see, there was an extraneous influence acting in the same direction. Finally, the rigour of Stoic morality had been strained to such a pitch that its professors were driven to admit the complete ideality of virtue. Their sage had never shown himself on earth, at least within the historical period; and the whole world of human interests being, from the rational point of view, either a delusion or a failure, stood in permanent contradiction to their optimistic theory of Nature. The Sceptics were quite aware of this practical approximation to their own views, and sometimes took advantage of it to turn the tables on their opponents with telling effect. Thus, on the occasion of that philosophical embassy with an account of which the present chapter began, when a noble Roman playfully observed to Carneades, ‘You must think that I am not a Praetor as I am not a sage, and that Rome is neither a city nor a state,’ the great Sceptic replied, turning to his colleague Diogenes, ‘That is what my Stoic friend here would say.’262 And Plutarch, in two sharp attacks on the Stoics, written from the Academic point of view, and probably compiled from documents of a much earlier period,263 charges them with outraging common sense by their wholesale practical negations, to at least as great an extent as the Sceptics outraged it by their suspense of judgment. How the ethical system of Stoicism was modified so as to meet these criticisms has been related in a former chapter; and we have just seen how Posidonius, by his partial return to the Platonic psychology, with its division between reason and impulse, contributed to a still further change in the same conciliatory sense.

VII.

We have now reached a point in history where the Greek intellect seems to be struck with a partial paralysis, continuing for a century and a half. During that period, its activity—what there is of it—is shown only in criticism and erudition. There is learning, there is research, there is acuteness, there is even good taste, but originality and eloquence are extinct. Is it a coincidence, or is it something more, that this interval of sterility should occur simultaneously with the most splendid period of Latin literature, and that the new birth of Greek culture should be followed by the decrepitude and death of the Latin muse? It is certain that in modern Europe, possessing as it does so many independent sources of vitality, the flowering-times of different countries rarely coincide; England and Spain, from the middle of the sixteenth to the middle of the seventeenth century, being the only instances that we can recall of two countries almost simultaneously reaching the highest point of their literary development. Possibly, during the great age of Latin literature, all the most aspiring Greeks found employment as tutors in Roman families; while the reading public of the West were too much absorbed by the masterpieces composed in their own language, or too elated with the consciousness of a new superiority, to encourage the rivalry of those from whom they had wrested not only poetical independence, but also, what till then had never been disputed with the Greeks, supreme dominion in the world of mind. It is, at any rate, significant that while Greek was the favourite language of Roman lovers in the time of Lucretius and again in the time of Juvenal, there are no allusions to its having been employed by them during the intermediate period.264 Be this as it may, from the fall of the Republic to the time of Trajan, philosophy, like poetry and eloquence—or at least all philosophy that was positive and practical—became domiciled in Rome, and received the stamp of the Roman character. How Stoicism was affected by the change has been pointed out in a former chapter. What we have now to study is chiefly the reaction of Rome on the Greek mind, and its bearing on the subsequent development of thought.

This reaction had begun to make itself felt long before the birth of a philosophical literature in the Latin language. It may be traced to the time when the lecture-halls at Athens were first visited by Roman students, and Greek professors first received on terms of intimate companionship into the houses of Roman nobles. In each instance, but more especially in the latter, not only would the pupil imbibe new ideas from the master, but the master would suit his teaching to the tastes and capacities of the pupil. The result would be an intellectual condition somewhat resembling that which attended the popularisation of philosophy in Athens during the latter half of the fifth century B.C.; and all the more so as speculation had already spontaneously reverted to the Sophistic standpoint. The parallel will be still more complete if we take the word Sophist in its original and comprehensive sense. We may then say that while Carneades, with his entrancing eloquence and his readiness to argue both sides of a question, was the Protagoras of the new movement; Panaetius, the dignified rationalist and honoured friend of Laelius and the younger Scipio, its Prodicus; and Posidonius, the astronomer and encyclopaedic scholar, its Hippias, Phaedrus the Epicurean was its Anaxagoras or Democritus.

The Epicurean philosophy was, in fact, the first to gain a footing in Rome; and it thereby acquired a position of comparative equality with the other schools, to which it was not really entitled, but which it has ever since succeeded in maintaining. The new doctrine fell like a spark on a mass of combustible material. The Romans were full of curiosity about Nature and her workings; full of contempt for the degrading Etruscan superstitions which hampered them at every turn, and the falsity of which was proving too much even for the official gravity of their state-appointed interpreters; full of impatience at the Greek mythology which was beginning to substitute itself for the severe abstractions of their own more spiritual faith;265 full of loathing for the Asiatic orgies which were being introduced into the highest society of their own city. Epicureanism offered them a complete and easily intelligible theory of the world, which at the same time came as a deliverance from supernatural terrors. The consequence was that its different parts were thrown out of perspective, and their relative importance almost reversed. Originally framed as an ethical system with certain physical and theological implications, it was interpreted by Lucretius, and apparently also by his Roman predecessors,266 as a scientific and anti-religious system, with certain references to conduct neither very prominently brought forward nor very distinctly conceived. And we know from the contents of the papyrus rolls discovered at Herculaneum, that those who studied the system in its original sources paid particular attention to the voluminous physical treatises of Epicurus, as well as to the theological works of his successors. Nor was this change of front limited to Epicureanism, if, as we may suspect, the rationalistic direction taken by Panaetius was due, at least in part, to a similar demand on the side of his Roman admirers.

But what had happened once before when philosophy was taken up by men of the world, repeated itself on this occasion. Attention was diverted from speculative to ethical problems, or at least to issues lying on the borderland between speculation and practice, such as those relating to the criterion of truth and the nature of the highest good. On neither of these topics had Epicureanism a consistent answer to give, especially when subjected to the cross-examination of rival schools eager to secure Roman favour for their own doctrines. Stated under any form, the Epicurean morality could not long satisfy the conquerors of the world. To some of them it would seem a shameful dereliction of duty, to others an irksome restraint on self-indulgence, while all would be alienated by its declared contempt for the general interests of culture and ambition. Add to this that the slightest acquaintance with astronomy, as it was then taught in Hellenic countries, would be fatal to a belief in the Epicurean physics, and we shall understand that the cause for which Lucretius contended was already lost before his great poem saw the light.

The requirements which Epicureanism failed to meet, were, to a great extent, satisfied by Stoicism. This philosophy had, from a comparatively early period, won the favour of a select class, but had been temporarily overshadowed by the popularity of its hedonistic and anti-religious rival, when a knowledge of the Greek systems first became diffused through Italy. The uncouth language of the early Stoics and the apparently unpractical character of their theories doubtless exercised a repellent effect on many who were not out of sympathy with their general spirit. These difficulties were overcome first by Panaetius, and then, to a still greater extent, by Posidonius, the elder contemporary and friend of Pompeius and Cicero, who was remarkable not only for his enormous learning but also for his oratorical talent.267 It seems probable that the lessons of this distinguished man marked the beginning of that religious reaction which eventually carried all before it. We have already seen how he abandoned the rationalistic direction struck out by his predecessor, Panaetius; and his return to the old Stoic orthodoxy may very well have responded to a revival of religious feeling among the educated Roman public, who by this time must have discovered that there were other ways of escaping from superstition besides a complete rejection of the supernatural.

The triumph of Stoicism was, however, retarded by the combined influence of the Academic and Peripatetic schools. Both claimed the theory of a morality founded on natural law as a doctrine of their own, borrowed from them without acknowledgment by the Porch, and restated under an offensively paradoxical form. To a Roman, the Academy would offer the further attraction of complete immunity from the bondage of a speculative system, freedom of enquiry limited only by the exigencies of practical life, and a conveniently elastic interpretation of the extent to which popular faiths might be accepted as true. If absolute suspense of judgment jarred on his moral convictions, it was ready with accommodations and concessions. We have seen how the scepticism of Carneades was first modified by Philo, and then openly renounced by Philo’s successor, Antiochus. Roman influence may have been at work with both; for Philo spent some time in the capital of the empire, whither he was driven by the events of the first Mithridatic War; while Antiochus was the friend of Lucullus and the teacher of Cicero.268

VIII.

The greatest of Roman orators and writers was also the first Roman that held opinions of his own in philosophy. How much original thought occurs in his voluminous contributions to the literature of the subject is more than we can determine, the Greek authorities on which he drew being known almost exclusively through the references to them contained in his disquisitions. But, judging from the evidence before us, carefully sifted as it has been by German scholars, we should feel disposed to assign him a foremost rank among the thinkers of an age certainly not distinguished either for fertility or for depth of thought. It seems clear that he gave a new basis to the eclectic tendencies of his contemporaries, and that this basis was subsequently accepted by other philosophers whose speculative capacity has never been questioned. Cicero describes himself as an adherent of the New Academy, and expressly claims to have reasserted its principles after they had fallen into neglect among the Greeks, more particularly as against his own old master Antiochus, whose Stoicising theory of cognition he agrees with Philo in repudiating.269 Like Philo also, he bases certainty on the twofold ground of a moral necessity for acting on our beliefs,270 and the existence of moral intuitions, or natural tendencies to believe in the mind itself;271 or, perhaps, more properly speaking, on the single ground of a moral sense. This, as already stated, was unquestionably a reproduction of the Platonic ideas under their subjective aspect. But in his general views about the nature and limits of human knowledge, Cicero leaves the Academy behind him, and goes back to Socrates. Perhaps no two men of great genius could be more unlike than these two,—for us the most living figures in ancient history if not in all history,—the Roman being as much a type of time-servingness and vacillation as the Athenian was of consistency and resolute independence. Yet, in its mere external results, the philosophy of Socrates is perhaps more faithfully reproduced by Cicero than by any subsequent enquirer; and the differences between them are easily accounted for by the long interval separating their ages from one another. Each set out with the same eager desire to collect knowledge from every quarter; each sought above all things for that kind of knowledge which seemed to be of the greatest practical importance; and each was led to believe that this did not include speculations relating to the physical world; one great motive to the partial scepticism professed by both being the irreconcilable disagreement of those who had attempted an explanation of its mysteries. The deeper ground of man’s ignorance in this respect was stated somewhat differently by each; or perhaps we should say that the same reason is expressed in a mythical form by the one and in a scientific form by the other. Socrates held that the nature of things is a secret which the gods have reserved for themselves; while, in Cicero’s opinion, the heavens are so remote, the interior of the earth so dark, the mechanism of our own bodies so complicated and subtle, as to be placed beyond the reach of fruitful observation.272 Nor did this deprivation seem any great hardship to either, since, as citizens of great and free states, both were pre-eminently interested in the study of social life; and it is characteristic of their common tendency that both should have been not only great talkers and observers but also great readers of ancient literature.273

With regard to ethics, there is, of course, a great difference between the innovating, creative genius of the Greek and the receptive but timid intelligence of the Roman. Yet the uncertainty which, in the one case, was due to the absence of any fixed system, is equally present in the other, owing to the embarrassment of having so many systems among which to choose. Three ethical motives were constantly present to the thoughts of Socrates: the utility of virtue, from a material point of view, to the individual; its social necessity; and its connexion with the dual constitution of man as a being composed of two elements whereof the one is infinitely superior to the other; but he never was able, or never attempted to co-ordinate them under a single principle. His successors tried to discover such a principle in the idea of natural law, but could neither establish nor apply it in a satisfactory manner. Cicero reproduces the Socratic elements, sometimes in their original dispersion and confusion, sometimes with the additional complication and perplexity introduced by the idea through which it had been hoped to systematise and reconcile them. To him, indeed, that idea was even more important than to the Greek moralists; for he looked on Nature as the common ground where philosophy and untrained experience might meet for mutual confirmation and support.274 We have seen how he adopted the theory—as yet not very clearly formulated—of a moral sense, or general faculty of intuition, from Philo. To study and obey the dictates of this faculty, as distinguished from the depraving influence of custom, was his method of arriving at truth and right. But if, when properly consulted, it always gave the same response, a similar unanimity might be expected in the doctrines of the various philosophical schools; and the adhesion of Academicians, Peripatetics, and Stoics to the precept, Follow Nature, seemed to demonstrate that such an agreement actually existed. Hence Cicero over and over again labours to prove that their disputes were merely verbal, and that Stoicism in particular had borrowed its ethics wholesale from his own favourite sect. Yet from time to time their discrepancies would force themselves on his notice; and by none have the differences separating Stoicism from its rivals been stated with more clearness, concision, and point.275 These relate to the absolute self-sufficingness of virtue, its unity, and the incompatibility of emotion with its exercise. But Cicero seems to have regarded the theory of preference and rejection as a concession to common sense amounting to a surrender of whatever was parodoxical and exclusive in the Stoic standpoint.276 And with respect to the question round which controversy raged most fiercely, namely, whether virtue was the sole or merely the chief condition of happiness, Cicero, as a man of the world, considered that it was practically of no consequence which side prevailed.277 It would be unfair to blame him for not seeing, what the stricter school felt rather than saw, that the happiness associated with goodness was not of an individual but of a social character, and therefore could not properly be compared with objects of purely individual desire, such as health, wealth, friends, and worldly fame.

But even taken in its mildest form, there were difficulties about Greek idealism which still remained unsolved. They may be summed up in one word, the necessity of subordinating all personal and passionate feelings to a higher law, whatever the dictates of that law may be. Of such self-suppression few men were less capable than Cicero. Whether virtue meant the extirpation or merely the moderation of desire and emotion, it was equally impossible to one of whom Macaulay has said, with not more severity than truth, that his whole soul was under the dominion of a girlish vanity and a craven fear.278 Such weak and well-intentioned natures almost always take refuge from their sorrows and self-reproaches in religion; and probably the religious sentiment was more highly developed in Cicero than in any other thinker of the age. Here also a parallel with Socrates naturally suggests itself. The relation between the two amounts to more than a mere analogy; for not only was the intellectual condition of old Athens repeating itself in Rome, but the religious opinions of all cultivated Romans who still retained their belief in a providential God, were, to an even greater extent than their ethics, derived through Stoicism from the great founder of rational theology. Cicero, like Socrates, views God under the threefold aspect of a creator, a providence, and an informing spirit:—identical in his nature with the soul of man, and having man for his peculiar care. With regard to the evidence of his existence, the teleological argument derived from the structure of organised beings is common to both; the argument from universal belief, doubtless a powerful motive with Socrates, is more distinctly put forward by Cicero; and while both regard the heavenly luminaries as manifest embodiments of the divine essence, Cicero is led by the traditions of Plato, Aristotle, and the Stoics, to present the regularity of their movements as the most convincing revelation of a superhuman intelligence, and to identify the outermost starry sphere with the highest God of all.279 Intimately associated with this view is his belief in the immortality of the soul, which he supposes will return after death to the eternal and unchangeable sphere whence it originally proceeded.280 But his familiarity with the sceptical arguments of Carneades prevented Cicero from putting forward his theological beliefs with the same confidence as Socrates; while, at the same time, it enabled him to take up a much more decided attitude of hostility towards the popular superstitions from which he was anxious, so far as possible, to purify true religion.281 To sum up: Cicero, like Kant, seems to have been chiefly impressed by two phenomena, the starry heavens without and the moral law within; each in its own way giving him the idea of unchanging and everlasting continuance, and both testifying to the existence of a power by which all things are regulated for the best. But the materialism of his age naturally prevented him from regarding the external order as a mere reflex or lower manifestation of the inward law by which all spirits feel themselves to be members of the same intelligible community.

We have illustrated the position of Cicero by reference to the master who, more than any other Greek philosopher, seems to have satisfied his ideal of perfect wisdom. We must now observe that nothing is better calculated to show how inadequate was the view once universally taken of Socrates, and still, perhaps, taken by all who are not scholars, than that it should be applicable in so many points to Cicero as well. For, while the influence of the one on human thought was the greatest ever exercised by a single individual, the influence of the other was limited to the acceleration of a movement already in full activity, and moreover tending on the whole in a retrograde direction. The immeasurable superiority of the Athenian lies in his dialectical method. It was not by a mere elimination of differences that he hoped to establish a general agreement, but by reasoning down from admitted principles, which were themselves to be the result of scientific induction brought to bear on a comprehensive and ever-widening area of experience. Hence his scepticism, which was directed against authority, tended as much to stimulate enquiry as that of the Roman declaimer, which was directed against reason, tended to deaden or to depress it. Hence, also, the political philosophy of Socrates was as revolutionary as that of his imitator was conservative. Both were, in a certain sense, aristocrats; but while the aristocracy of the elegant rhetorician meant a clique of indolent and incapable nobles, that of the sturdy craftsman meant a band of highly-trained specialists maintained in power by the choice, the confidence, and the willing obedience of an intelligent people. And while the religion of Cicero was a blind reliance on providence supplemented by priestcraft in this world, with the hope, if things came to the worst, of a safe retreat from trouble in the next; the religion of Socrates was an active co-operation with the universal mind, an attempt to make reason and the will of God prevail on earth, with the hope, if there was any future state, of carrying on in it the intellectual warfare which alone had made life worth living here. No less a contrast could be expected between the orator who turned to philosophy only for the occupation of a leisure hour, or for relief from the pangs of disappointed ambition, and the thinker who gave her his whole existence as the elect apostle and martyr of her creed.

IX.

We have seen what was the guiding principle of Cicero’s philosophical method. By interrogating all the systems of his time, he hoped to elicit their points of agreement, and to utilise the result for the practical purposes of life. As actually applied, the effect of this method was not to reconcile the current theories with one another, nor yet to lay the foundation of a more comprehensive philosophy, but to throw back thought on an order of ideas which, from their great popularity, had been incorporated with every system in turn, and, for that very reason, seemed to embody the precise points on which all were agreed. These were the idea of Nature, the idea of mind or reason, and the idea of utility. We have frequently come across them in the course of the present work. Here it will suffice to recall the fact that they had been first raised to distinct consciousness when the results of early Greek thought were brought into contact with the experiences of Greek life, and more especially of Athenian life, in the age of Pericles. As originally understood, they gave rise to many complications and cross divisions, arising from what was considered to be their mutual incompatibility or equivalence. Thus Nature was openly rejected by the sceptical Sophists, ignored by Socrates, and, during a long period of his career, treated with very little respect by Plato; reason, in its more elaborate forms, was slighted by the Cynics, and employed for its own destruction by the Megarians, in both cases as an enemy to utility; while to Aristotle the pure exercise of reason was the highest utility of any, and Nature only a lower manifestation of the same idealising process. At a later period, we find Nature accepted as a watchword by Stoics, Epicureans, and Sceptics alike, although, of course, each attached a widely different meaning to the term; the supremacy of reason, without whose aid, indeed, their controversies could not have been carried on, is recognised with similar unanimity; and each sect lays exclusive stress on the connexion of its principles with human happiness, thus making utility the foremost consideration in philosophy. Consequently, to whatever system a Roman turned, he would recognise the three great regulative conceptions of Greek thought, although frequently enveloped in a network of fine-spun distinctions and inferences which to him must have seemed neither natural nor reasonable nor useful. On the other hand, apart from such subtleties, he could readily translate all three into terms which seemed to show that, so far from being divided by any essential incompatibility, they did but represent different aspects of a single harmonious ideal. Nature meant simplicity, orderliness, universality, and the spontaneous consentience of unsophisticated minds. Reason meant human dignity, especially as manifested in the conquest of fear and of desire. And whatever was natural and reasonable seemed to satisfy the requirements of utility as well. It might seem also that these very principles were embodied in the facts of old Roman life and of Rome’s imperial destiny. The only question was which school of Greek philosophy gave them their clearest and completest interpretation. Lucretius would have said that it was the system of Epicurus; but such a misconception was only rendered possible by the poet’s seclusion from imperial interests, and, apparently, by his unacquaintance with the more refined forms of Hellenic thought. Rome could not find in Epicureanism the comprehensiveness, the cohesion, and the power which marked her own character, and which she only required to have expressed under a speculative form. Then came Cicero, with his modernised rhetorical version of what he conceived to be the Socratic philosophy. His teaching was far better suited than that of his great contemporary to the tastes of his countrymen, and probably contributed in no small degree to the subsequent discredit of Epicureanism; yet, by a strange irony, it told, to the same extent, in favour of a philosophy from which Cicero himself was probably even more averse than from the morality of the Garden. In his hands, the Academic criticism had simply the effect of dissolving away those elements which distinguished Stoicism from Cynicism; while his eclecticism brought into view certain principles more characteristic of the Cynics than of any other sect. The Nature to whose guidance he constantly appeals was, properly speaking, not a Socratic but a Sophistic or Cynic idea; and when the Stoics appropriated it, they were only reclaiming an ancestral possession. The exclusion of theoretical studies and dialectical subtleties from philosophy was also Cynic; the Stoic theology when purified, as Cicero desired that it should be purified, from its superstitious ingredients, was no other than the naturalistic monotheism of Antisthenes; and the Stoic morality without its paradoxes was little more than an ennobled Cynicism. The curve described by thought was determined by forces of almost mechanical simplicity. The Greek Eclectics, seeking a middle term between the Academy and the Porch, had fallen back on Plato; Cicero, pursuing the same direction, receded to Socrates; but the continued attraction of Stoicism drew him to a point where the two were linked together by their historical intermediary, the Cynic school. And, by a singular coincidence, the primal forms of Roman life, half godlike and half brutal, were found, better than anything in Hellenic experience, to realise the ideal of a sect which had taken Heracles for its patron saint. Had Diogenes searched the Roman Forum, he would have met with a man at every step.

Meanwhile the morality of Stoicism had enlisted a force of incalculable importance on its behalf. This was the life and death of the younger Cato. However narrow his intellect, however impracticable his principles, however hopeless his resistance to the course of history, Cato had merits which in the eyes of his countrymen placed him even higher than Caesar; and this impression was probably strengthened by the extraordinary want of tact which the great conqueror showed when he insulted the memory of his noblest foe. Pure in an age of corruption, disinterested in an age of greed, devotedly patriotic in an age of selfish ambition, faithful unto death in an age of shameless tergiversation, and withal of singularly mild and gentle character, Cato lived and died for the law of conscience, proving by his example that if a revival of old Roman virtue were still possible, only through the lessons of Greek philosophy could this miracle be wrought. And it was equally clear that Rome could only accept philosophy under a form harmonising with her ancient traditions, and embodying doctrines like those which the martyred saint of her republican liberties had professed.

The Roman reformers were satisfied to call themselves Stoics; and, in reviewing the Stoic system, we saw to what an extent they welcomed and developed some of its fundamental thoughts. But we have now to add that the current which bore them on had its source deeper down than the elaborate combinations of Zeno and Chrysippus, and entered into the composition of every other system that acted on the Roman intellect simultaneously with theirs. Thus whatever forces co-operated with Stoicism had the effect not of complicating but of simplifying its tendencies, by bringing into exclusive prominence the original impulse whence they sprang, which was the idea of Natural Law. Hence the form ultimately assumed by Roman thought was a philosophy of Nature, sometimes appearing more under a Stoic, and sometimes more under a Cynic guise. Everything in Roman poetry that is not copied from Greek models or inspired by Italian passion—in other words, its didactic, descriptive, and satiric elements—may be traced to this philosophy. Doubtless the inculcation of useful arts, the delight in beautiful scenery, the praises of rustic simplicity, the fierce protests against vice under all its forms, and the celebration of an imperial destiny, which form the staple of Rome’s national literature, spring from her own deepest life; but the quickening power of Greek thought was needed to develope them into articulate expression.

There is, indeed, nothing more nobly characteristic of the Hellenic spirit, especially as organised by Socrates, than its capacity not only for communicating, but for awakening ideas; thus enabling all the nations among which it spread to realise the whole potential treasure of theoretical and practical energy with which they were endowed. And, from this point of view, we may say that what seems most distinctively proper to Rome—the triumphant consciousness of herself as a world-conquering and world-ruling power—came to her from Greece, and under the form of a Greek idea, the idea of providential destiny. It was to make his countrymen understand the fateful character and inevitable march of her empire that Polybius composed his great history; it was also by a Greek that the most successful of her early national epics was sung; and when at last her language was wrought into an adequate instrument of literary expression—thanks also to Greek rhetorical teaching,—and the culture of her children had advanced so far that they could venture to compete with the Greeks on their own ground, it was still only under forms suggested by Stoicism that Virgil could rewrite the story of his country’s dedication to her predestined task.

That Virgil was acquainted with this philosophy and had accepted some of its principal conclusions is evident from a famous passage in the Sixth Aeneid,282 setting forth the theory of a universal and all-penetrating soul composed of fiery matter, whence the particular souls of men and animals are derived, by a process likened to the scattering and germination of seeds; from another equally famous passage in the Fourth Eclogue,283 describing the periodical recurrence of events in the same order as before; and also, although to a less extent, from his acceptance of the Stoic astronomy in the Georgics;284 a circumstance which, by the way, renders it most unlikely that he looked up to Lucretius as an authority in physical science.285 But even apart from this collateral evidence, one can see that the Aeneid is a Stoic poem. It is filled with the ideas of mutation and vicissitude overruled by a divinely appointed order; of the prophetic intimations by which that order is revealed; of the obedience to reason by which passion is subdued; and of the faith in divine goodness by which suffering is made easy to be borne. And there are also gleams of that universal humanity familiar to Stoicism, which read to some like an anticipation of the Christian or the modern spirit, but which really resemble them only as earlier manifestations of the same great philosophical movement.

This analogy with subsequent developments is aided, so far as it goes, by the admixture of a certain Platonic element with Virgil’s Stoicism, shown chiefly by the references to an antenatal existence of the soul, introduced for the purpose of bringing Rome’s future heroes on the scene. This, however, is the last example of an attempt on the part of a Roman writer to combine Plato’s teaching with Stoicism.286 At a time when the Romans were more conscious of their literary dependence on Greece than was the case after the Augustan age had reached its zenith, they were probably drawn by the beauty of its literary form to study a system which could otherwise interest them but little. Thus, not only is Cicero full of admiration for Plato—as, indeed, might be expected with so highly cultivated a disciple of the Academy—but Cato, according to the well-known story, spent his last hours reading and re-reading the Phaedo; and his nephew Brutus also occupied an intermediate position between the Old Academy and the Porch. The Roman love of simplification and archaism induced subsequent thinkers either to let Platonism drop altogether, or to study those elements in which it differed from the pure naturalistic doctrine under their Pythagorean form. It may even be doubted whether Virgil’s psychology is not derived from Pythagoras rather than from Plato; Ovid, so far as he philosophises at all, is unquestionably a follower of the former;287 and in the moral teaching of the Sextii, who flourished under Augustus, Pythagorean principles are blended with Stoicism.288 It is another manifestation of the same effort to grasp every Greek doctrine by its roots, that Horace should proclaim himself the disciple of Aristippus rather than of Epicurus.289 Even he, however, feels himself drawn with advancing years towards the nobler faith which was now carrying all before it.290

With Seneca and his contemporaries, Stoicism has shaken itself free from alien ingredients, and has become the accepted creed of the whole republican opposition, being especially pronounced in the writings of the two young poets, Persius and Lucan. But in proportion as naturalistic philosophy assumed the form of a protest against vice, luxury, inhumanity, despotism, and degradation, or of an exhortation to welcome death as a deliverance from those evils, in the same proportion did it tend to fall back into simple Cynicism; and on this side also it found a ready response, not only in the heroic fortitude, but also in the brutal coarseness and scurrility of the Roman character. Hence the Satires of the last great Roman poet, Juvenal, are an even more distinct expression of Cynic than the epic of Virgil had been of Stoic sentiment. Along with whatever was good and wholesome in Cynicism there is the shameless indecency of the Cynics, and their unquestioning acceptance of mendicancy and prostitution as convenient helps to leading a natural and easily contented life. And it may be noticed that the free-thinking tendencies which distinguished the Cynics from the Stoics are also displayed in Juvenal’s occasional denunciations of superstition.

X.

Thus the final effect of its communion with the Roman mind was not so much to develope Greek philosophy any further, or to reconcile its warring sects with one another, as to aid in their decomposition by throwing them back on the earlier forms whence they had sprung. Accordingly we find that the philosophic activity of Hellas immediately before and after the Christian era—so far as there was any at all—consisted in a revival of the Pythagorean and Cynic schools, accompanied by a corresponding resuscitation of primitive Scepticism. This last takes the shape of a very distinct protest against the fashionable naturalism of the age, just as the scepticism of Protagoras and Gorgias—if our view be correct—had once been called forth by the naturalism of Prodicus and Hippias. The principal representative, if not the founder, of Neo-Scepticism was AenesidÊmus, who taught in Alexandria, when we are not informed, but probably after the middle of the first century A.D.291 An avowed disciple of Pyrrho, his object was to reassert the sceptical principle in its original purity, especially as against the Academicians, whom he charged with having first perverted and then completely abandoned it.292 AenesidÊmus would hear nothing of probabilities nor of moral certainties. He also claimed to distinguish himself from the Academicians by refusing to assert even so much as that nothing can be asserted; but it appears that, in this point, he had been fully anticipated by Arcesilaus and Carneades.293 For the rest, his own Scepticism recalls the method of Gorgias and Protagoras much more distinctly than the method of the New Academy—a fresh illustration of the archaic and revivalist tendencies displayed by philosophy at this period. In other words, it is not against the reasoning processes that his criticisms are directed, but against the theory of causation on the objective side, and against the credibility of our immediate perceptions on the subjective side.294 But, in both directions, he has worked out the difficulties of the old Sophists with a minuteness and a precision unknown to them; and some of his points have been found worth repeating in a different connexion by modern critics. Thus, in analysing the theory of causation, he draws attention to the plurality of causes as an obstacle to connecting any given consequent with one antecedent more than with another; to the illegitimate assumption that the laws inferred from experience hold good under unknown conditions; to the arbitrary assumption of hypothetical causes not evinced by experience; and to the absurdity of introducing a new difficulty for the purpose of explaining an old one.295 With regard to causation itself, AenesidÊmus seems to have resolved it into action and reaction, thus eliminating the condition of antecedence and consequence, without which it becomes unintelligible.296

The Alexandrian Sceptic’s general arguments against the possibility of knowledge resolve themselves into a criticism of what Sir W. Hamilton called Natural Realism, somewhat complicated and confused by a simultaneous attack on the theory of natural morality conceived as something eternal and immutable. They are summed up in the famous ten Tropes. Of these the first three are founded on the conflicting sensations produced by the same object when acting on different animals—as is inferred from the marked contrast presented by their several varieties of origin and structure,—on different men, and on the different senses of the same individual. The fourth, which has evidently an ethical bearing, enlarges on the changes in men’s views caused by mental and bodily changes, according to their health, age, disposition, and so forth. The next five Tropes relate to circumstances connected with the objects themselves: their distance and position as regards the spectator, the disturbance produced in their proper action by external influences such as air and light, together with the various membranes and humours composing the organs of sense through which they are apprehended; their quantitative variation, involving as it does opposite effects on the senses, or as with medicines, on the health; the law of relativity, according to which many things are only known when taken in company with others, such as double and half, right and left, whole and part; comparative frequency or rarity of occurrence, as with comets, which, while really of much less importance than the sun, excite much more interest from their being so seldom seen. Finally, the tenth Trope is purely ethical, and infers the non-existence of a fixed moral standard from the divergent and even opposite customs prevailing among different nations.297

In his attacks on the prevalent theories of ethics, AenesidÊmus again reminds us both of Protagoras and of modern agnosticism. According to him, the general disagreement of mankind proves, among other things, that there is no definable highest good—it is neither virtue, nor pleasure, nor knowledge.298 In the absence of any dogmatic teaching on the subject at the time when he lived, Protagoras could not give an opinion with regard to the summum bonum; but Plato’s famous dialogue represents him as one who, from his point of view, would be unwilling to admit the possibility of introducing fixed principles into conduct; and in like manner, Mr. Herbert Spencer, while accepting the hedonistic principle, gives it such an extremely general signification that he is thrown back on the sceptical principle of leaving everyone free to follow his own inclinations, provided that, in so doing, he does not interfere with the liberty of others.

The parallel between AenesidÊmus and Protagoras would become still more complete were it true that the Alexandrian philosopher also sought to base his Scepticism on the Heracleitean theory of Nature, arguing that contradictory assertions are necessitated by the presence of contradictory properties in every object.

That AenesidÊmus held this view is stated as a fact by Sextus, whose testimony is here corroborated by Tertullian, or rather by Tertullian’s informant, Soranus. We find, however, that Zeller, who formerly accepted the statement in question as true, has latterly seen reason to reject it. AenesidÊmus cannot, he thinks, have been guilty of so great an inconsistency as to base his Scepticism on the dogmatic physics of Heracleitus. And he explains the agreement of the ancient authorities by supposing that the original work of AenesidÊmus contained a critical account of the Heracleitean theory, that this was misinterpreted into an expression of his adhesion to it by Soranus, and that the blunder was adopted at second-hand by both Sextus and Tertullian.299

It is, at any rate, certain that the successors of AenesidÊmus adhered to the standpoint of Pyrrho. One of them, Agrippa, both simplified and strengthened the arguments of the school by reducing the ten Tropes to five. The earlier objections to human certainty were summed up under two heads: the irreconcilable conflict of opinions on all subjects; and the essential relativity of consciousness, in which the percipient and the perceived are so intimately united that what things in themselves are cannot possibly be discovered. The other three Tropes relate to the baselessness of reasoning. They were evidently suggested by Aristotle’s remarks on the subject. The process of proof cannot be carried backwards ad infinitum, nor can it legitimately revolve in a circle. Thus much had already been admitted, or rather insisted on by the great founder of logic. But the Sceptics could not agree to Aristotle’s contention, that demonstration may be based on first principles of self-evident certainty. They here fell back on their main argument; that the absence of general agreement on every point is fatal to the existence of such pretended axioms. A still further simplification was effected by the reduction of the five Tropes to two—that all reasoning rests on intuition, and that men’s intuitions are irreconcilably at variance with one another.300 As against true science, the sceptical Tropes are powerless, for the validity of its principles has nothing to do with their general acceptance. They are laid before the learner for his instruction, and if he chooses to regard them as either false or doubtful, the misfortune will be his and not theirs. But as against all attempts to constrain belief by an appeal to authority, the Tropes still remain invincible. Whether the testimony invoked be that of ancient traditions or of a supposed inward witness, there is always the same fatal objection that other traditions and other inward witnesses tell quite a different story. The task of deciding between them must, after all, be handed over to an impersonal reason. In other words, each individual must judge for himself and at his own risk, just as he does in questions of physical science.

We have already observed that Scepticism among the ancients was often cultivated in connexion with some positive doctrine which it indirectly served to recommend. In the case of its last supporters, this was the study of medicine on an empirical as opposed to a deductive method. The Sceptical contention is that we cannot go beyond appearances; the empirical contention is, that all knowledge comes to us from experience, and that this only shows us how phenomena are related to one another, not how they are related to their underlying causes, whether efficient or final. These allied points of view have been brought into still more intimate association by modern thought, which, as will be shown in the concluding chapter, has sprung from a modified form of the ancient Scepticism, powerfully aided by a simultaneous development of physical science. At the same time, the new school have succeeded in shaking off the narrowness and timidity of their predecessors, who were still so far under the influence of the old dogmatists as to believe that there was an inherent opposition between observation and reasoning in the methods of discovery, between facts and explanations in the truths of science, and between antecedence and causation in the realities of Nature. In this respect, astronomy has done more for the right adjustment of our conceptions than any other branch of knowledge; and it is remarkable that Sextus Empiricus, the last eminent representative of ancient Scepticism, and the only one (unless Cicero is to be called a Sceptic) whose writings are still extant, should expressly except astronomy from the destructive criticism to which he subjects the whole range of studies included in what we should call the university curriculum of his time.301 We need not enter into an analysis of the ponderous compilation referred to; for nearly every point of interest which it comprises has already been touched on in the course of our investigation; and Sextus differs only from his predecessors by adding the arguments of the New Academy to those of Protagoras and Pyrrho, thus completing the Sceptical cycle. It will be enough to notice the singular circumstance that so copious and careful an enumeration of the grounds which it was possible to urge against dogmatism—including, as we have seen, many still employed for the same or other purposes,—should have omitted the two most powerful solvents of any. These were left for the exquisite critical acumen of Hume to discover. They relate to the conception of causation, and to the conception of our own personality as an indivisible, continuously existing substance, being attempts to show that both involve assumptions of an illegitimate character. Sextus comes up to the very verge of Hume’s objection to the former when he observes that causation implies relation, which can only exist in thought;302 but he does not ask how we come to think such a relation, still less does he connect it with the perception of phenomenal antecedence; and his attacks on the various mental faculties assumed by psychologists pass over the fundamental postulate of personal identity, thus leaving Descartes what seemed a safe foundation whereon to rebuild the edifice of metaphysical philosophy.

The effect aimed at by ancient Scepticism under its last form was to throw back reflection on its original starting-point. Life was once more handed over to the guidance of sense, appetite, custom, and art.303 We may call this residuum the philosophy of the dinner-bell. That institution implies the feeling of hunger, the directing sensation of sound, the habit of eating together at a fixed time, and the art of determining time by observing the celestial revolutions. Even so limited a view contains indefinite possibilities of expansion. It involves the three fundamental relations that other philosophies have for their object to work out with greater distinctness and in fuller detail: the relation between feeling and action, binding together past, present, and future in the consciousness of personal identity; the relation of ourselves to a collective society of similarly constituted beings, our intercourse with whom is subject from the very first to laws of morality and of logic; and, finally, the relation in which we stand, both singly and combined, to that universal order by which all alike are enveloped and borne along, with its suggestions of a still larger logic and an auguster morality springing from the essential dependence of our individual and social selves on an even deeper identity than that which they immediately reveal. We have already had occasion to observe how the noble teaching of Plato and the Stoics resumes itself in a confession of this threefold synthesis; and we now see how, putting them at their very lowest, nothing less than this will content the claims of thought. Thus, in less time than it took Berkeley to pass from tar-water to the Trinity, we have led our Sceptics from their philosophy of the dinner-bell to a philosophy which the Catholic symbols, with their mythologising tendencies, can but imperfectly represent. And to carry them with us thus far, nothing more than one of their own favourite methods is needed. Wherever they attempt to arrest the progress of enquiry and generalisation, we can show them that no real line of demarcation exists. Let them once admit the idea of a relation connecting the elements of consciousness, and it will carry them over every limit except that which is reached when the universe becomes conscious of itself. Let them deny the idea of a relation, and we may safely leave them to the endless task of analysing consciousness into elements which are feelings and nothing more. The magician in the story got rid of a too importunate familiar by setting him to spin ropes of sand. The spirit of Scepticism is exorcised by setting it to divide the strands of reason into breadthless lines and unextended points.

What influence Scepticism exercised on the subsequent course of Greek thought is difficult to determine. If we are to believe Diogenes Laertius, who flourished in the second quarter of the third century A.D., every school except Epicureanism had at that time sunk into utter neglect;304 and it is natural to connect this catastrophe with the activity of the Sceptics, and especially of Sextus Empiricus, whose critical compilation had appeared not long before. Such a conclusion would be supported by the circumstance that Lucian, writing more than fifty years earlier, directs his attacks on contemporary philosophy chiefly from the Sceptical standpoint; his Hermotimus in particular being a popularised version of the chief difficulties raised from that quarter. Still it remains to be shown why the criticism of the Greek Humanists, of Pyrrho, and of the New Academy should have produced so much more powerful an effect under their revived form than when they were first promulgated; and it may be asked whether the decline of philosophy should not rather be attributed to the general barbarisation of the Roman empire at that period.

We have also to consider in what relation the new Scepticism stood to the new Platonism by which, in common with every other school, it was eventually either displaced or absorbed. The answer usually given to this question is that the one was a reaction from the other. It is said that philosophy, in despair of being able to discover truth by reason, took refuge in the doctrine that it could be attained by supernatural revelation; and that this doctrine is the characteristic mark distinguishing the system of Plotinus from its predecessors. That a belief in the possibility of receiving divine communications was widely diffused during the last centuries of polytheism is, no doubt, established, but that it ever formed more than an adjunct to Neo-Platonism seems questionable; and there is no evidence that we are aware of to show that it was occasioned by a reaction from Scepticism. As a defence against the arguments of Pyrrho and his successors, it would, in truth, have been quite unavailing; for whatever objections applied to men’s natural perceptions, would have applied with still greater force to the alleged supernatural revelation. Moreover, the mystical element of Neo-Platonism appears only in its consummation—in the ultimate union of the individual soul with the absolute One; the rest of the system being reasoned out in accordance with the ordinary laws of logic, and in apparent disregard of the Sceptical attacks on their validity.

The truth is that critics seem to have been misled by a superficial analogy between the spiritualistic revival accomplished by Plotinus, and the Romantic revival which marked the beginning of the present century. The two movements have, no doubt, several traits in common; but there is this great difference between them, that the latter was, what the former was not, a reaction against individualism, agnosticism, and religious unbelief. The right analogy will be found not by looking forward but by looking back. It will then be seen that the Neo-Platonists were what their traditional name implies, disciples of Plato, and not only of Plato but of Aristotle as well. They stood in the same relation to the systems which they opposed as that in which the two great founders of spiritualism had stood to the naturalistic and humanist schools of their time—of course with whatever modifications of a common standpoint were necessitated by the substitution of a declining for a progressive civilisation. Like Plato also, they were profoundly influenced by the Pythagorean philosophy, with its curious combination of mystical asceticism and mathematics. And, to complete the analogy, they too found themselves in presence of a powerful religious reaction, against the excesses of which, like him, they at first protested, although with less than his authority, and only, like him, to be at last carried away by its resistless torrent. It is to the study of this religious movement that we must now address ourselves, before entering on an examination of the latest form assumed by Greek philosophy among the Greeks themselves.

Note.—It does not enter into the plan of this work to study the educational and social aspects of Greek philosophy under the Roman Empire. Those who wish for information on the subject should consult Capes’s Stoicism, Martha’s Moralistes sous l’Empire Romain, Renan’s Marc-AurÈle, chap, iii., Aubertin’s SÉnÈque et Saint Paul, Havet’s Christianisme et ses Origines, Vol. II., Gaston Boissier’s Religion Romaine, Duruy’s Histoire Romaine, chap, lxi., FriedlÄnder’s Darstellungen aus der Sittengeschichte Rom’s, Vol. III., chap. v. (5th ed.), and Bruno Bauer’s Christus und die CÄsaren.