In the Essay on the Human Understanding, Bk. IV., ch. x., Locke attempts to prove the existence of a God, which, though God has given us no innate idea of Himself, he regards as "the most obvious truth that reason discerns," and as resting on evidence equal to mathematical certainty. Morality is, he maintains, entirely based upon the Will of God. If there were no God, there would, for him, be no morality, and this is the reason of his denying to Atheists the protection of the State. In the chapter on the Existence of God he says expressly that this truth is so fundamental that "all genuine morality depends thereon," and almost at the beginning of the Essay (Bk. I., ch. iii., § 6), while acknowledging that "several moral rules may receive from mankind a very general approbation, without either knowing or admitting the true ground of morality," he maintains that such true ground "can only be the Will and Law of a God, who sees men in the dark, has in his hand rewards and punishments, and power enough to call to account the proudest offender." Again, "the Rule prescribed by God is the true and only measure of Virtue." But how are we to ascertain this rule? "God has by an inseparable connexion joined Virtue and Public Happiness together," and hence we have only to ascertain, by the use of the natural reason, what on the whole conduces most to the public welfare, in order to know the Divine Will. The rules, when arrived at, have a "moral and eternal obligation," and are enforced by fear of "the Hell God has ordained for the punishment of those that transgress them."

This form of Utilitarianism, resting on a theological basis and enforced by theological sanctions, is precisely that which afterwards became so popular and excited so much attention, when adopted in the well-known work of Paley. According to this system, we do what is right simply because God commands it, and because He will punish us if we disobey His orders. "By the fault is the rod, and with the transgression a fire ready to punish it." But, notwithstanding the divine origin and the divine sanction of morality, its measure and test are purely human. Each man is required by the Law of God to do all the good and prevent all the evil that he can, and, as good and evil are resolved into pleasure and pain, the ultimate test of virtue or moral conduct comes to be its conduciveness to promote the pleasures and avert the pains of mankind. Bentham, whose ethical system, it may be noticed, differed mainly from that of Locke and Paley by not being based on a theological foundation, extends the scope of morality to all sentient creatures, capable of pleasure and pain.

I shall not here criticise Locke's theory so far as it is common to other utilitarian systems of ethics, but shall simply content myself with pointing out that its influence on subsequent writers has seldom, if ever, been sufficiently recognized. The theological foundation, however, on which it rests, and which is peculiar among the more prominent moralists of modern times to Locke and Paley, is open to an objection so grave and obvious, that it is curious it did not occur to the authors themselves. If what is right and wrong, good and evil, depends solely on the Will of God, how can we speak of God Himself as good? Goodness, as one of the Divine attributes, would then simply mean the conformity of God to His own Will. An elder contemporary of Locke, Ralph Cudworth, so clearly saw the difficulties and contradictions involved in this view of the nature and origin of morality, that he devotes a considerable portion of his Treatise concerning Eternal and Immutable Morality (which, however, was not published till 1731) to its refutation. And, possibly, Locke himself may have been conscious of some inconsistency between this theory (the ordinary one amongst the vulgar, though a comparatively rare one amongst philosophers) and the attribution of goodness to God. For, in his chapter on our knowledge of the existence of God, he never expressly mentions the attribute of goodness as pertaining to the Divine Nature, though in other parts of the Essay it must be acknowledged that he incidentally does so. Moralists and philosophical theologians have generally escaped the difficulties of Locke's theory by making right or moral goodness depend not on the Will but on the Nature of God, or else by regarding it as an ultimate fact, incapable of explanation, or, lastly, by resolving it into the idea of happiness or pleasure, which itself is then regarded as an ultimate fact in the constitution of sentient beings.

Two other characteristic doctrines of Locke's ethical system ought here to be mentioned, though it is impossible, within the space at my command, to discuss them. One is that morality is a science capable of demonstration. The other, which is elaborately set out in the chapter on Power in the Essay (Bk. II., ch. xxi.), is that, though the Agent is free to act as he wills, the Will itself is invariably determined by motives. This solution of the well-worn controversy on the Freedom of the Will is almost identical with that offered by Hobbes before and by Hume afterwards, and is usually known as Determinism.

We have seen that the main sanctions of morality, with Locke, are the rewards and punishments of a future state. But how are we assured of future existence? Only by Revelation. "Good and wise men," indeed, "have always been willing to believe that the soul was immortal;" but "though the Light of Nature gave some obscure glimmering, some uncertain hopes of a future state, yet Human Reason could attain to no clearness, no certainty about it, but it was Jesus Christ alone who brought life and immortality to light through the gospel." (Third Letter to the Bp. of Worcester.) But if the main sanctions of morality are those of a future state, and if it is Christians alone who feel anything approaching to an assurance of such a state, surely morality must come with somewhat weak credentials to the rest of mankind. And Locke doubtless believed this to be the case. But then, if this be so, Christians ought to be prepared to tolerate a much lower morality than their own in dealing with men of other faiths—one of the many inconvenient consequences which result from founding morality on a theological basis.

Under the head of Locke's theological writings may be included the Treatise on the Reasonableness of Christianity with the two Vindications of it—the Essays on Toleration, and the Commentaries on some of the Epistles of St. Paul. The Reasonableness of Christianity was published in 1695, and may be taken as expressing Locke's most matured opinions on the questions of which it treats, though, in reading it, we must always bear in mind the caution and reticence which any writer of that time who diverged from the strict path of orthodoxy was obliged to observe. There can be no doubt that his object in this work was to commend what he regarded as the fundamental truths of Christianity to the attention of reflecting men, and to vindicate to the Christian religion what he conceived to be its legitimate influence over mankind. But, in trying to effect this his main object, he seems also to have wished to correct what he regarded as certain popular errors, and to bring back Christianity to the norm of the Scriptures, instead of implicitly following the Fathers, the Councils, and the received theology of the Churches and the Schools. He attempted, he tells us, to clear his mind of all preconceived notions, and, following the lead of the Scriptures, of which he assumed the infallibility, to see whither they would lead him. We may certainly trust his own assertion that he had no thoughts of writing in the interest of any particular party, though, at the same time, it was evidently his aim to extract from the Scriptures a theory as much as possible in accordance with the requirements of human reason, or, in other words, to reconcile the divine light with the natural light of man. The main results at which he arrived may be stated very briefly, as follows. Adam had been created immortal, but, by falling from the state of perfect obedience, "he lost paradise, wherein was tranquillity and the tree of life; that is, he lost bliss and immortality." "In Adam all die," and hence all his descendants are mortal. But this sentence is to be taken in its literal sense, and not in the signification that "every one descended of him deserves endless torment in hell-fire." For it seems "a strange way of understanding a law, which requires the plainest and directest words, that by death should be meant eternal life in misery." Much less can death be interpreted as a necessity of continual sinning. "Can the righteous God be supposed, as a punishment of our sin, wherewith He is displeased, to put man under the necessity of sinning continually, and so multiplying the provocation?" Here it will be seen Locke strikes at the root of the doctrines of the taint and guilt of original sin, doctrines which had long been stoutly opposed by the Arminians or Remonstrants with whom he had associated in Holland. But though it would have been an injustice to condemn men, for the fault of another, to a state of misery "worse than non-being," it was no wrong to deprive them of that to which they had no right, the exceptional condition of immortality. Adam's sin, then, subjected all men to death. But in Christ they have again been made alive, and "the life which Jesus Christ restores to all men is that life which they receive again at the resurrection." Now the conditions of our obtaining this gift are faith and repentance. But repentance implies the doing works meet for repentance; that is to say, leading a good life. And faith implies a belief not only in the one invisible, eternal, omnipotent God, but also in Jesus as the Messiah, who was born of a virgin, rose again from the grave, and ascended into heaven. When Christ came on earth, the minds of men had become so far blinded by sense and lust and superstition that it required some visible and unmistakable assertion of God's majesty and goodness to bring them back to true notions of Him and of the Divine Law which He had set them. "Reason, speaking ever so clearly to the wise and virtuous, had never authority enough to prevail on the multitude." For the multitude were under the dominion of the priests, and the "priests everywhere, to secure their empire, had excluded reason from having anything to do in religion." "In this state of darkness and error, in reference to the 'true God,' our Saviour found the world. But the clear revelation he brought with him dissipated this darkness, made the 'one invisible true God' known to the world; and that with such evidence and energy, that polytheism and idolatry have nowhere been able to withstand it." And, as he revealed to mankind a clear knowledge of the one true God, so also he revealed to them a clear knowledge of their duty, which was equally wanting.

"Natural religion, in its full extent, was nowhere that I know taken care of by the force of natural reason. It should seem, by the little that has hitherto been done in it, that it is too hard a task for unassisted reason to establish morality in all its parts, upon its true foundation, with a clear and convincing light. And it is at least a surer and shorter way to the apprehensions of the vulgar and mass of mankind, that one manifestly sent from God, and coming with visible authority from him, should, as a king and law-maker, tell them their duties and require their obedience, than leave it to the long and sometimes intricate deductions of reason to be made out to them. Such trains of reasoning the greater part of mankind have neither leisure to weigh, nor, for want of education and use, skill to judge of.... You may as soon hope to have all the day-labourers and tradesmen, the spinsters and dairy-maids, perfect mathematicians, as to have them perfect in ethics this way. Hearing plain commands is the sure and only course to bring them to obedience and practice. The greater part cannot learn, and therefore they must believe."

It is true that reason quickly apprehends and approves of these truths, when once delivered, but "native and original truth is not so easily wrought out of the mine as we, who have it delivered already dug and fashioned into our hands, are apt to imagine;" moreover, "experience shows that the knowledge of morality by mere natural light (how agreeable soever it be to it) makes but a slow progress, and little advance in the world."

The evidence of Christ's mission is to be found in the miracles, the occurrence and the divine origin of which Locke, both here and in the paper on Miracles published among his Posthumous Works, appears to have thought it impossible to gainsay. "The miracles he did were so ordered by the divine providence and wisdom, that they never were nor could be denied by any of the enemies or opposers of Christianity." And "this plain matter of fact being granted, the truth of our Saviour's doctrine and mission unavoidably follows." But once acknowledge the truth of Christ's mission, and the rule of life is evident. "To one who is once persuaded that Jesus Christ was sent by God to be a King, and a Saviour of those who do believe in him, all his commands become principles; there needs no other proof for the truth of what he says, but that he said it. And then there needs no more, but to read the inspired books, to be instructed; all the duties of morality lie there clear, and plain, and easy to be understood."

This, then, is Locke's scheme of a plain and reasonable Christianity. "These are articles that the labouring and illiterate man may comprehend. This is a religion suited to vulgar capacities, and the state of mankind in this world, destined to labour and travail." "The writers and wranglers in religion," indeed, "fill it with niceties, and dress it up with notions, which they make necessary and fundamental parts of it, as if there were no way into the church but through the academy or lyceum;" but the religion which he had enunciated was, Locke conceived, the religion of Christ and the Apostles, of the New Testament and of Common-Sense. That Locke, though he had no respect for the dogmas of the Church, never seriously questioned the supernatural birth of Christ, the reality of the Christian miracles, or the infallibility of the Scriptures, is abundantly evident. On the last point his testimony is quite as emphatic as on the former two. In the Reasonableness of Christianity, speaking of the writers of the Epistles, he says:—"These holy writers, inspired from above, writ nothing but truth." And, to the same effect, in his Second Reply to Stillingfleet, he writes:—"My lord, I read the revelation of the holy scripture with a full assurance that all it delivers is true." The word "infallible" is applied, without any misgiving or qualification, to the contents of Scripture, though he assumes to each individual believer full liberty of interpretation. During his residence in Holland, as we have already seen, he appears to have entertained some doubts on this subject, but, at a later period, those doubts appear to have been finally laid.

Notwithstanding, however, the sincerity and simplicity of Locke's religious faith, the doctrines which he maintained must have represented but a very attenuated Christianity to the partisans of the two great religious parties which were at that time nominally the strongest in England. A Christianity which did not recognize the hereditary taint of original sin, and which passed over the mystery of the Atonement in silence, must have been as distasteful to one party as a Christianity which ignored Church authority and the exclusive privileges of the apostolical succession must have been to the other. And to the zealots of both parties alike, a statement of doctrine which was silent on the mystery of the Trinity, or rather which seemed to imply that the Son, though miraculously conceived, was not co-equal or co-eternal with the Father, and which, by implication, appeared to suggest that, though the righteous would be endowed with immortality, the torments of the wicked would have an end, might well seem not to deserve the name of Christianity at all. We need feel no wonder, then, that the appearance of Locke's work was followed by a bitter theological controversy which lasted during the rest of his life, and beyond it. Of these attacks upon him, and his Vindications, I have spoken in a previous chapter.

Whether Locke's presentation of Christianity is really more "reasonable" than the ancient and venerable creeds which it attempted to replace, is a question which might be debated now with fully as much vigour as in his own day. On the one hand, it might be maintained that a religion which has no mysteries, which has been pared down to the requirements of human reason, has ceased to be a religion altogether. That which is behind the veil can only be partially revealed in our present condition and to our present faculties. Now we know, and can know, only in part. On the other hand, it might be said that the "reason" is quite as much offended by the doctrines which Locke retained as by those which he rejected. It is necessary, however, to recollect, in estimating his position, that the theological difficulties of his age were moral and metaphysical rather than scientific and critical. The moral consciousness of many reflecting men was shocked by doctrines like those of original sin, predestination, the atonement, and everlasting punishment. Nor could they reconcile to their reason the seeming contradictions of the doctrine of a Triune God. But the study of nature had not advanced sufficiently far, or been sufficiently widely spread, to make the idea of supernatural intervention in the ordinary course of affairs, such as is constantly presented to us in the Biblical history, any serious or general stumbling-block. Much less had the criticism of the Sacred Text, or the comparison of it with the sacred books of other religions, become sufficiently common, or been carried out with sufficient rigour, to disturb, to any great extent, the received opinion that the Bible was literally, or, at least, substantially, the Word of God. Hence the via media on which Locke took his stand, though it might have been impossible to a philosopher of the next generation, seemed reasonable and natural enough to speculative men among his contemporaries. And for him it had at least this advantage, that it enabled him honestly to reconcile the conclusions of his philosophy with the singular piety and devoutness of his disposition. Had his religious doubts proceeded further than they did, there would probably have ensued a mental struggle which, besides causing him much personal unhappiness, might have deprived posterity of the more important of his works.

Of The Letters on Toleration, though deeply interesting to the generation in which they were written, a very brief account will here suffice. Their main thesis is, that the jurisdiction of the civil magistrate does not extend to the regulation of religious worship or to controlling the expression of religious beliefs, except so far as that worship or those beliefs may interfere with the ends of civil government. The respective provinces of a commonwealth and a church are strictly defined, and are shown to be perfectly distinct. "The boundaries on both sides are fixed and immovable. He jumbles heaven and earth together, the things most remote and opposite, who mixes these societies, which are in their original, end, business, and in everything, perfectly distinct and infinitely different from each other." But it may be asked, are there no speculative opinions, no tenets, actual or possible, of any religious community which should be restrained by the Civil Magistrate? The answer is, yes,—

"First, No opinions contrary to human society, or to those moral rules which are necessary to the preservation of civil society, are to be tolerated by the magistrate."

Secondly, after speaking of those who maintain such positions as that "faith is not to be kept with heretics," that "kings excommunicated forfeit their crowns and kingdoms," that "dominion is founded in grace," he proceeds:

"These, therefore, and the like, who attribute unto the faithful, religious, and orthodox, that is, in plain terms, unto themselves, any peculiar privilege or power above other mortals in civil concernments, or who, upon pretence of religion, do challenge any manner of authority over such as are not associated with them in their ecclesiastical communion: I say these have no right to be tolerated by the magistrate, as neither those that will not own and teach the duty of tolerating all men in matters of mere religion. For what do all these and the like doctrines signify, but that they may, and are ready upon any occasion to seize the government, and possess themselves of the estates and fortunes of their fellow-subjects, and that they only ask leave to be tolerated by the magistrates so long until they find themselves strong enough to effect it?"

"Thirdly, That church can have no right to be tolerated by the magistrate, which is constituted upon such a bottom that all those who enter upon it do thereby ipso facto deliver themselves up to the protection and service of another prince. For by this means the magistrate would give way to the settling of a foreign jurisdiction in his own country, and suffer his own people to be listed, as it were, for soldiers against his own government."

"Lastly, Those are not at all to be tolerated who deny the being of God. Promises, covenants, and oaths, which are the bonds of human society, can have no hold upon an atheist. The taking away of God, though but even in thought, dissolves all."

The practical result of Locke's exceptions, at the time at which he wrote, would have been to exclude from toleration Roman Catholics, Atheists, and perhaps certain sects of Antinomians. Roman Catholics, however, would not have been excluded on the ground of their belief in Transubstantiation, as was actually the case, but because of those tenets which, in Locke's judgment, made them bad or impossible subjects.

Locke was not by any means the first of English writers who had advocated a wide toleration in religion. Bacon, in his remarkable Essay on Unity in Religion, had laid down, in passing, a position which is almost identical with that developed at length in the Letters on Toleration. During the Civil Wars, the Independents, as a body, had been led on by their theories of Church Government and of individual inspiration to maintain, on principle, and accord, in practice, a large measure of religious toleration. Amongst divines of the Church of England, Hales of Eton, Chillingworth, and Jeremy Taylor, had honourably distinguished themselves above the mass of their brethren by expressly advocating, or unmistakably suggesting, the same humane doctrines. The practical conclusions at which Taylor arrives, in his noble work on the Liberty of Prophesying, bear a close resemblance to those of Locke's Letters on Toleration, while the theoretical considerations on which he mainly founds them, namely, the difficulty of discovering religious truth, and the small number of theological propositions of which we can entertain anything like certainty, might be regarded as anticipating, to no small extent, some of the views expressed in the Reasonableness of Christianity. Locke's attention had been turned to these questions at an early period of his life by the religious dissensions which accompanied the Civil Wars, and, during the years immediately preceding the publication of the first Letter on Toleration, his interest in them must have been sustained not only by the events which were then happening in England, but by the common topics of conversation amongst his Arminian or Remonstrant friends in Holland. The peculiarities of their position and the tendencies of their doctrines had, at an early date, forced on the Dutch Remonstrants, just as on the English Independents, the necessity of claiming and defending a wide toleration. What, perhaps, mainly distinguishes Locke's pamphlets is their thorough outspokenness, the political rather than the theological character of the argument, and the fact that they are expressly dedicated to the subject of Toleration, instead of treating of it incidentally.

The sharp line of demarcation which Locke draws between the respective provinces of civil and religious communities seems to lead logically to the inexpediency of maintaining a state establishment of religion. The independence which he claims for all religious societies would be inconsistent with the control which the State always has exercised, and always must exercise, in the affairs of any spiritual body on which it confers special privileges. This conclusion, we can hardly doubt, he would have readily accepted. As far back as 1669, he had objected to one of the articles in the "Fundamental Constitutions of Carolina," providing for the establishment and endowment of the Church of England in that colony. Even at the present day, men who adopt the most liberal and tolerant opinions on religious questions are divided as to the expediency or inexpediency of recognizing a State-Church; but those who embrace the latter alternative may, perhaps, fairly claim Locke as having been on their side.

The system contained in the Reasonableness of Christianity had been constructed solely on an examination of the Gospels and the Acts of the Apostles. In addition to the difficulties of interpretation attaching to the Epistles, Locke had urged that "they were writ to them who were in the faith and true Christians already, and so could not be designed to teach them the fundamental articles and points necessary to salvation." But to one who accepted the divine inspiration and infallibility of all parts of Scripture, it was essential to establish the consistency and coherence of the whole. Accordingly, in the later years of his life, Locke set himself the task of explaining the Epistles. This work seems to have been undertaken more for his own satisfaction and that of Lady Masham and his more immediate friends, than with any distinct design of publication. Nor did his commentaries see the light till after his death.

The commentatorial work accomplished by Locke consists of paraphrases and notes on the Epistles to the Galatians, Corinthians, Romans, and Ephesians, together with An Essay for the understanding of St. Paul's Epistles by consulting St. Paul himself.

It is needless to remark that these commentaries are distinguished by sound, clear sense, and by a manifest spirit of candour and fairness. They are often quoted with approbation by commentators of the last century. But in the present more advanced state of grammatical and historical criticism, they are likely to remain, as they now are, the least consulted of all his works. The method, object, and drift of all Locke's theological writings is the same. Regardless of ecclesiastical tradition, but assuming the infallibility of the Scriptures, he attempts to arrive at the true and essential import of God's Revelation to man. His theoretical conclusion is that the articles of saving faith are few and simple, and the practical application of that conclusion is that, not only within the ample fold of Christianity, but even without it, all men, whose conduct is consistent with the maintenance of civil society, should be the objects of our goodwill and charity.