1. Relation of the Sophistic Philosophy to the Anaxagorean Principle.—Anaxagoras had formed the conception of mind, and in this had recognized thought as a power above the objective world. Upon this newly conquered field the Sophistic philosophy now began its gambols, and with childish wantonness delighted itself in setting at work this power, and in destroying, by means of a subjective dialectic, all objective determinations. The Sophistic philosophy—though of far more significance from its relation to the culture of the age than from its philosophy—had for its starting principle the breach which Anaxagoras had commenced between the subjective and the objective,—the Ego and the external world. The subject, after recognizing himself as something higher than the objective world, and especially as something above the laws of the state, above custom and religious tradition and the popular faith, in the next place attempted to prescribe laws for this objective world, and instead of beholding in it the historical manifestation of reason, he looked upon it only as an exanimated matter, upon which he might exercise his will.

The Sophistic philosophy should be characterized as the clearing up reflection. It is, therefore, no philosophical system, for its doctrines and affirmations exhibit often so popular and even trivial a character that for their own sake they would merit no place at all in the history of philosophy. It is also no philosophical school in the ordinary sense of the term,—for Plato cites a vast number of persons under the common name of “Sophists,”—but it is an intellectual and widely spread direction of the age, which had struck its roots into the whole moral, political, and religious character of the Athenian life of that time, and which may be called the Athenian clearing up period.

2. Relation of the Sophistic Philosophy to the Universal Life of that Age.—The Sophistic philosophy is, theoretically, what the whole Athenian life during the Peloponnesian war was practically. Plato justly remarks in his Republic that the doctrines of the Sophists only expressed the very principles which guided the course of the great mass of men of that time in their civil and social relations, and the hatred with which they were pursued by the practical statesmen, clearly indicates the jealousy with which the latter saw in them their rivals and the destroyers of their polity. If the absoluteness of the empirical subject—i. e. the view that the individual Ego can arbitrarily determine what is true, right and good,—is in fact the theoretical principle of the Sophistic philosophy, so does this in a practical direction, as an unlimited Egoism meet us in all the spheres of the public and private life of that age. The public life had become an arena of passion and selfishness; those party struggles which racked Athens during the Peloponnesian war had blunted and stifled the moral feeling; every individual accustomed himself to set up his own private interest above that of the state and the common weal, and to seek in his own arbitrariness and advantage the measuring rod for all his actions. The Protagorean sentence that “the man is the measure of all things” became practically carried out only too faithfully, and the influence of the orator in the assemblies of the people and the courts, the corruptibility of the great masses and their leaders, and the weak points which showed to the adroit student of human nature the covetousness, vanity, and factiousness of others around him, offered only too many opportunities to bring this rule into practice. Custom had lost its weight; the laws were regarded as only an agreement of the majority, the civil ordinance as an arbitrary restriction, the moral feeling as the effect of the policy of the state in education, the faith in the gods as a human invention to intimidate the free power of action, while piety was looked upon as a statute which some men have enacted and which every one else is justified in using all his eloquence to change. This degradation of a necessity, which is conformable to nature and reason, and which is of universal validity,—to an accidental human ordinance, is chiefly the point in which the Sophistic philosophy came in contact with the universal consciousness of the educated class of that period, and we cannot with certainty determine what share science and what share the life may have had in this connection,—whether the Sophistic philosophy found only the theoretical formula for the practical life and tendencies of the age, or whether the moral corruption was rather a consequence of that destructive influence which the principles of the Sophists exerted upon the whole course of contemporaneous thought.

It would be, however, to mistake the spirit of history if we were only to bewail the epoch of the Sophists instead of admitting for it a relative justification. These phenomena were in part the necessary product of the collective development of the age. The faith in the popular religion fell so suddenly to the ground simply because it possessed in itself no inner, moral support. The grossest vices and acts of baseness could all be justified and excused from the examples of mythology. Even Plato himself, though otherwise an advocate of a devout faith in the traditional religion, accuses the poets of his nation with leading the very moral feeling astray, through the unworthy representations which they had spread abroad concerning the gods and the hero world. It was moreover unavoidable that the advancing science should clash with tradition. The physical philosophers had already long lived in open hostility to the popular religion, and the more convincingly they demonstrated by analogies and laws that many things which had hitherto been regarded as the immediate effect of Divine omnipotence, were only the results of natural causes, so much the more easily would it happen that the educated classes would become perplexed in reference to all their previous convictions. It was no wonder then that the transformed consciousness of the time should penetrate all the provinces of art and poesy; that in sculpture, wholly analogous to the rhetoric art of the Sophistic philosophy, the emotive should occupy the place of the elevated style; that Euripides, the sophist among tragedians, should bring the whole philosophy of the time and its manner of moral reflection upon the stage; and that, instead of like the earlier poets, bringing forward his actors to represent an idea, he should use them only as means to excite a momentary emotion or some other stage effect.

3. Tendencies of the Sophistic Philosophy.—To give a definite classification of the Sophistic philosophy, which should be derived from the conception of the general phenomena of the age, is exceedingly difficult, since, like the French “clearing up” of the last century, it entered into every department of knowledge. The Sophists directed the universal culture of the time. Protagoras was known as a teacher of virtue, Gorgias as a rhetorician and politician, Prodicus as a grammarian and teacher of synonyms, Hippias as a man of various attainments, who besides astronomical and mathematical studies busied himself with a theory of mnemonics; others took for their problem the art of education, and others still the explanation of the old poets; the brothers Euthydemus and Dionysidorus gave instruction in the bearing of arms and military tactics; many among them, as Gorgias, Prodicus, and Hippias, were intrusted with embassies: in short the Sophists, each one according to his individual tendency, took upon themselves every variety of calling and entered into every sphere of science; their method is the only thing common to all. Moreover the relation of the Sophists to the educated public, their striving after popularity, fame and money, disclose the fact that their studies and occupations were for the most part controlled, not by a subjective scientific interest, but by some external motive. With that roving spirit which was an essential peculiarity of the later Sophists, travelling from city to city, and announcing themselves as thinkers by profession—and giving their instructions with prominent reference to a good recompense and the favor of the rich private classes, it was very natural that they should discourse upon the prominent questions of universal interest and of public culture, with occasional reference also to the favorite occupation of this or that rich man with whom they might be brought in contact. Hence their peculiar strength lay far more in a formal dexterity, in an acuteness of thought and a capacity of bringing it readily into exercise, in the art of discourse than in any positive knowledge; their instruction in virtue was given either in positive dogmatism or in empty bombast, and even where the Sophistic philosophy became really polymathic, the art of speech still remained as the great thing. So we find in Xenophon, Hippias boasting that he can speak repeatedly upon every subject and say something new each time, while we hear it expressly affirmed of others, that they had no need of positive knowledge in order to discourse satisfactorily upon every thing, and to answer every question extemporaneously; and when many Sophists make it a great point to hold a well-arranged discourse about something of the least possible significance (e. g. salt), so do we see that with them the thing was only a means while the word was the end, and we ought not to be surprised that in this respect the Sophistic philosophy sunk to that empty technicality which Plato in his PhÆdrus, on account of its want of character, subjects to so rigid a criticism.

4. The Significance of the Sophistic Philosophy from its Relation to the Culture of the Age.—The scientific and moral defect of the Sophistic philosophy is at first view obvious; and, since certain modern writers of history with over-officious zeal have painted its dark sides in black, and raised an earnest accusation against its frivolity, immorality, and greediness for pleasure, its conceitedness and selfishness, and bare appearance of wisdom and art of dispute—it needs here no farther elucidation. But the point in it most apt to be overlooked is the merit of the Sophists in their effect upon the culture of the age. To say, as is done, that they had only the negative merit of calling out the opposition of Socrates and Plato, is to leave the immense influence and the high fame of so many among them, as well as the revolution which they brought about in the thinking of a whole nation, an inexplicable phenomenon. It were inexplicable that e. g. Socrates should attend the lectures of Prodicus, and direct to him other students, if he did not acknowledge the worth of his grammatical performances or recognize his merit for the soundness of his logic. Moreover, it cannot be denied that Protagoras has hit upon many correct principles of rhetoric, and has satisfactorily established certain grammatical categories. Generally may it be said of the Sophists, that they threw among the people a fulness in every department of knowledge; that they strewed about them a vast number of fruitful germs of development; that they called out investigations in the theory of knowledge, in logic and in language; that they laid the basis for the methodical treatment of many branches of human knowledge, and that they partly founded and partly called forth that wonderful intellectual activity which characterized Athens at that time. Their greatest merit is their service in the department of language. They may even be said to have created and formed the Attic prose. They are the first who made style as such a separate object of attention and study, and who set about rigid investigations respecting number and the art of rhetorical representation. With them Athenian eloquence, which they first incited, begins. Antiphon as well as Isocrates—the latter the founder of the most flourishing school of Greek rhetoric—are offshoots of the Sophistic philosophy. In all this there is ground enough to regard this whole phenomenon as not barely a symptom of decay.

5. Individual Sophists.—The first, who is said to have been called, in the received sense, Sophist, is Protagoras of Abdera, who flourished about 440 B. C. He taught, and for wages, in Sicily and in Athens, but was driven out of the latter place as a reviler of the gods, and his book concerning the gods was burnt by the herald in the public market-place. It began with these words: “I can know nothing concerning the gods, whether they exist or not; for we are prevented from gaining such knowledge not only by the obscurity of the thing itself, but by the shortness of the human life,” In another writing he develops his doctrine concerning knowing or not-knowing. Starting from the Heraclitic position that every thing is in a constant flow, and applying this preËminently to the thinking subject, he taught that the man is the measure of all things, who determines in respect of being that it may be, and of not-being that it may not be, i. e. that is true for the perceiving subject which he, in the constant movement of things and of himself, at every moment perceives and is sensible of—and hence he has theoretically no other relation to the external world than the sensuous apprehension, and practically no other than the sensuous desire. But now, since perception and sensation are as diverse as the subjects themselves, and are in the highest degree variable in the very same subject, there follows the farther result that nothing has an objective validity and determination, that contradictory affirmations in reference to the same object must be received as alike true, and that error and contradiction cannot be. Protagoras does not seem to have made any efforts to give these frivolous propositions a practical and logical application. According to the testimony of the ancients, a personal character worthy of esteem, cannot be denied him; and even Plato, in the dialogue which bears his name, goes no farther than to object to his complete obscurity respecting the nature of morality, while, in his Gorgias and Philebus, he charges the later Sophists with affirming the principles of immorality and moral baseness.

Next to Protagoras, the most famous Sophist was Gorgias. During the Peloponnesian war (426 B. C.), he came from Leontium to Athens in order to gain assistance for his native city against the encroachments of Syracuse, After the successful accomplishment of his errand he still abode for some time in Athens, but resided the latter part of his life in Thessaly, where he died about the same time with Socrates. The pompous ostentation of his external appearance is often ridiculed by Plato, and the discourses through which he was wont to exhibit himself display the same character, attempting, through poetical ornament, and florid metaphors, and uncommon words, and a mass of hitherto unheard of figures of speech, to dazzle and delude the mind. As a philosopher he adhered to the Eleatics, especially to Zeno, and attempts to prove upon the basis of their dialectic schematism, that universally nothing is, or if there could be a being, it would not be cognizable, or if cognizable it would not be communicable. Hence his writing bore characteristically enough the title—“Concerning Not-being or Nature.” The proof of the first proposition that universally nothing is, since it can be established neither as being nor as not-being, nor yet as at the same time both being and not-being, rests entirely upon the position that all existence is a space-filling existence (has place and body), and is in fact the final consequence which overturns itself, in other words the self-destruction of the hitherto physical method of philosophizing.

The later Sophists with reckless daring carried their conclusions far beyond Gorgias and Protagoras. They were for the most part free thinkers, who pulled to the ground the religion, laws, and customs of their birth. Among these should be named, prominently, the tyrant Critias, Polus, Callicles, and Thrasymachus. The two latter openly taught the right of the stronger as the law of nature, the unbridled satisfaction of desire as the natural right of the stronger, and the setting up of restraining laws as a crafty invention of the weaker; and Critias, the most talented but the most abandoned of the thirty tyrants, wrote a poem, in which he represented the faith in the gods as an invention of crafty statesmen. Hippias of Elis, a man of great knowledge, bore an honorable character, although he did not fall behind the rest in bombast and boasting; but before all, was Prodicus, in reference to whom it became a proverb to say—“as wise as Prodicus,” and concerning whom Plato himself and even Aristophanes never spoke without veneration. Especially famous among the ancients were his parenetical (persuasive) lectures concerning the choice of a mode of life (Xenophon’s Memorabilia, II. 1), concerning external good and its use, concerning life and death, &c., discourses in which he manifests a refined moral feeling, and his observation of life; although, through the want of a higher ethical and scientific principle, he must be placed behind Socrates, whose forerunner he has been called. The later generations of Sophists, as they are shown in the Euthydemus of Plato, sink to a common level of buffoonery and disgraceful strife for gain, and comprise their whole dialectic art in certain formulÆ for entangling fallacies.

6. Transition to Socrates and Characteristic of the Following Period.—That which is true in the Sophistic philosophy is the truth of the subjectivity, of the self-consciousness, i. e. the demand that every thing which I am to admit must be shown as rational before my own consciousness—that which is false in it is its apprehension of this subjectivity as nothing farther than finite, empirical egoistic subjectivity, i. e. the demand that my accidental will and opinion should determine what is rational; its truth is that it set up the principle of freedom, of self-certainty; its untruth is that it established the accidental will and notion of the individual upon the throne. To carry out now the principle of freedom and self-consciousness to its truth, to gain a true world of objective thought with a real and distinct content, by the same means of reflection which the Sophists had only used to destroy it, to establish the objective will, the rational thinking, the absolute or ideal in the place of the empirical subjectivity was the problem of the next advent in philosophy, the problem which Socrates took up and solved. To make the absolute or ideal subjectivity instead of the empirical for a principle, is to affirm that the true measure of all things is not my (i. e. the individual person’s) opinion, fancy and will; that what is true, right and good, does not depend upon my caprice and arbitrary determination, or upon that of any other empirical subject; but while it is my thinking, it is my thinking, the rational within me, which has to decide upon all those points. But my thinking, my reason, is not something specially belonging to me, but something common to every rational being; something universal, and in so far as I am a rational and thinking being, is my subjectivity a universal one. But every thinking individual has the consciousness that what he holds as right, as duty, as good or evil, does not appear as such to him alone but to every rational being, and that consequently his thinking has the character of universality, of universal validity, in a word—of objectivity. This then in opposition to the Sophistic philosophy is the standpoint of Socrates, and therefore with him the philosophy of objective thought begins. What Socrates could do in opposition to the Sophists was to show that reflection led to the same results as faith or obedience, hitherto without reflection, had done, and that the thinking man guided by his free consciousness and his own conviction, would learn to form the same judgments and take the same course to which life and custom had already and unconsciously induced the ordinary man. The position, that while the man is the measure of all things, it is the man as universal, as thinking, as rational, is the fundamental thought of the Socratic philosophy, which is, by virtue of this thought, the positive complement of the Sophistic principle.

With Socrates begins the second period of the Grecian philosophy. This period contains three philosophical systems, whose authors, standing to each other in the personal relation of teacher and pupil, represent three successive generations,—Socrates, Plato, Aristotle.