The works of Locke are on the shelves of most considerable libraries; but many men, now that the study of metaphysics is out of fashion, are appalled at the suggestion that they should read an essay in three volumes on the human understanding, evidently considering their own minds less worthy of study than their bodies or their estates. It may be worth while, therefore, to give a short summary of those theories, or discoveries of Locke which most modified French thought in the eighteenth century. The great thinker was born in 1632 and died in 1704. His principal works were published shortly after the English Revolution of 1688, but had been long in preparation; and the "Essay on the Human Understanding" is said to have occupied him not less than twenty years.
It is the principal doctrine of Locke that all ideas are derived from sensation and reflection. He acknowledges that "it is a received doctrine that men have native ideas and original characters stamped upon their minds in their very first being;" but he utterly rejects every such theory. It is his principal business to protest and argue against the existence of such "innate ideas." Virtue he believes to be generally approved because it is profitable, not on account of any natural leaning of the mind in its direction. Conscience "is nothing else but our own opinion or judgment of the moral rectitude or pravity of our own actions." Memory is the power in the mind to revive perceptions which it once had, with this additional perception annexed to them, that it has had them before. Wit lies in the assemblage of ideas, judgment in the careful discrimination among them. "Things are good or evil only in reference to pleasure or pain;" … "our love and hatred of inanimate, insensible beings is commonly founded on that pleasure or pain which we receive from their use and application any way to our senses, though with their destruction; but hatred or love of beings incapable of happiness or misery is often the uneasiness or delight which we find in ourselves, arising from a consideration of their very being or happiness. Thus the being and welfare of a man's children or friends, producing constant delight in him, he is said constantly to love them. But it suffices to note that our ideas of love and hatred are but dispositions of the mind in respect of pleasure or pain in general, however caused in us."
We have no clear idea of substance nor of spirit. Substance is that wherein we conceive qualities of matter to exist; spirit, that in which we conceive qualities of mind, as thinking, knowing, and doubting. The primary ideas of body are the cohesion of solid, and therefore separate parts, and a power of communicating motion by impulse. The ideas of spirit are thinking and will, or a power of putting body into motion by thought, and, which is consequent to it, liberty. The ideas of existence, mobility, and duration are common to both.
Locke's intelligence was clear enough to perceive that these two ideas, spirit and matter, stand on a similar footing. Less lucid thinkers have boldly denied the existence of spirit while asserting that of matter. Locke's system would not allow him to believe that either conception depended on the nature of the mind itself. He therefore rejected the claims of substance as unequivocally as those of spirit, declaring it to be "only an uncertain supposition of we know not what, i. e., of something whereof we have no particular, distinct, positive idea, which we take to be the substratum or support of those ideas we know." Yet he inclines on the whole toward materialism. "We have," he says, "the ideas of matter and thinking, but possibly shall never be able to know whether any mere material being thinks, or no; it being impossible for us, by the contemplation of our own ideas, without revelation, to discover whether omnipotency has not given to some system of matter, fitly disposed, a power to perceive and think, or else joined and fixed to matter so disposed a thinking immaterial substance, it being, in respect of our notions, not much more remote from our comprehension to conceive that God can, if he pleases, superadd to matter a faculty of thinking, than that he should superadd to it another substance, with a faculty of thinking; since we know not wherein thinking consists, nor to what sort of substances the Almighty has been pleased to give that power, which cannot be in any created being, but merely by the good pleasure and power of the Creator."… "All the great ends of morality and religion," he adds, "are well secured without philosophical proof of the soul's immateriality." As to our knowledge "of the actual existence of things, we have an intuitive knowledge of our own existence, and a demonstrative knowledge of the existence of God; of the existence of anything else, we have no other but a sensitive knowledge, which extends not beyond the objects present to our senses."[Footnote: Is not an intuitive knowledge suspiciously like an innate idea? Locke's Works, i. 38, 39, 72, 82, 137, 145, 231; ii. 10, 11, 21, 331, 360, 372 (Book i. ch. 3, 4, Book ii. ch. 1, 10, 11, 20, 23, Book iv. ch. 3).]
The eulogy of Locke in Voltaire's "Lettres Philosophiques" gave especial offense to the French churchmen. Voltaire writes to a friend that the censor might have been brought to give his approbation to all the letters but this one. "I confess," he adds, "that I do not understand this exception, but the theologians know more about it than I do, and I must take their word for it."[Footnote: Voltaire, li. 356 (Letter to Thieriot, 24 Feb. 1733).] The letter to which the censor objected was principally taken up with the doctrine of the materiality of the soul. "Never," says Voltaire, "was there perhaps a wiser or a more methodical spirit, a more exact logician, than Locke." … "Before him great philosophers had positively decided what is the soul of man; but as they knew nothing at all about it, it is very natural that they should all have been of different minds." And he adds in another part of the letter, "Men have long disputed on the nature and immortality of the soul. As to its immortality, that cannot be demonstrated, since people are still disputing about its nature; and since, surely, we must thoroughly know a created being to decide whether it is immortal or not. Human reason alone is so unable to demonstrate the immortality of the soul, that religion has been obliged to reveal it to us. The common good of all men demands that we should believe the soul to be immortal; faith commands it; no more is needed, and the matter is almost decided. It is not the same as to its nature; it matters little to religion of what substance is the soul, if only it be virtuous. It is a clock that has been given us to regulate, but the maker has not told us of what springs this clock is composed."[Footnote: Voltaire, xxxvii. 177, 182 (Lettres philosophiques. In the various editions of Voltaire's collected works published in the last century these letters do not appear as a series, but their contents is distributed among the miscellaneous articles, and those of the Dictionnaire philosophique. The reason for this was that the letters, having been judicially condemned, might have brought their publishers into trouble if they had appeared under their own title. Bengesco, ii. 9. Desnoiresterres, Voltaire à Cirey, 28, Voltaire, xxxvii. 113. In Beuchot's edition the letters appear in their original form).]
The "Lettres philosophiques" may be considered the first of Voltaire's polemic writings. They exhibit his mordant wit, his clear-sightedness and his moral courage. There is in them, perhaps, more real gayety, more spontaneous fun, than in his later books. Voltaire was between thirty-five and forty years old when they were written, and although he possessed to the end of his long life more vitality than most men, yet he was physically something of an invalid, and his many exiles and disappointments told upon his temper. From 1734, when these letters first appeared in France, to 1778, when he died, worn out with years, labors, quarrels, and honors, his activity was unceasing. He had many followers and many enemies, but hardly a rival. Voltaire was and is the great representative of a way of looking at life; a way which was enthusiastically followed in his own time, which is followed with equal enthusiasm to-day. This view he expressed and enforced in his numberless poems, tragedies, histories, and tales. It formed the burden of his voluminous correspondence. As we read any of them, his creed becomes clear to us; it is written large in every one of his more than ninety volumes. It may almost be said to be on every page of them. That creed may be stated as follows: We know truth only by our reason. That reason is enlightened only by our senses. What they do not tell us we cannot know, and it is mere folly to waste time in conjecturing. Imagination and feeling are blind leaders of the blind. All men who pretend to supernatural revelation or inspiration are swindlers, and those who believe them are dupes. It may be desirable, for political or social purposes, to have a favored religion in the state, but freedom of opinion and of expression should be allowed to all men, at least to all educated men; for the populace, with their crude ideas and superstitions, may be held in slight regard.
Voltaire's hatred was especially warm against the regular clergy. "Religion," he says, "can still sharpen daggers. There is within the nation a people which has no dealings with honest folk, which does not belong to the age, which is inaccessible to the progress of reason, and over which the atrocity of fanaticism preserves its empire, like certain diseases which attack only the vilest populace." The best monks are the worst, and those who sing "Pervigilium Veneris" in place of matins are less dangerous than such as reason, preach, and plot. And in another place he says that "a religious order should not a part of history." But it is well to notice that Voltaire's hatred of Catholicism and of Catholic monks is not founded on a preference for any other church. He thinks that theocracy must have been universal among early tribes, "for as soon as a nation has chosen a tutelary god, that god has priests. These priests govern the spirit of the nation; they can govern only in the name of their god, so they make him speak continually; they set forth his oracles, and all things are done by God's express commands." From this cause come human sacrifices and the most atrocious tyranny; and the more divine such a government calls itself, the more abominable it is.
All prophets are imposters. Mahomet may have begun as an enthusiast, enamored of his own ideas; but he was soon led away by his reveries; he deceived himself in deceiving others; and finally supported a doctrine which he believed to be good, by necessary imposture. Socrates, who pretended to have a familiar spirit, must have been a little crazy, or a little given to swindling. As for Moses, he is a myth, a form of the Indian Bacchus. The Koran (and consequently the Bible) may be judged by the ignorance of physics which it displays. "This is the touchstone of the books which, according to false religions, were written by the Deity, for God is neither absurd nor ignorant." Several volumes are devoted by Voltaire to showing the inconsistencies, absurdities and atrocities of the Old and New Testaments, and the abominations of the Jews.
The positive religious opinions of Voltaire are less important than his negations, for the work of this great writer was mainly to destroy. He was a theist, of wavering and doubtful faith. He was well aware that any profession of atheism might be dangerous, and likely to injure him at court and with some of his friends. He thought that belief in God and in a future life were important to the safety of society, and is said to have sent the servant out of the room on one occasion when one of the company was doubting the existence of the Deity, giving as a reason that he did not want to have his throat cut. Yet it is probable that his theism went a little deeper than this. He says that matter is probably eternal and self-existing, and that God is everlasting, and self-existing likewise. Are there other Gods for other worlds? It may be so; some nations and some scholars have believed in the existence of two gods, one good and one evil. Surely, nature can more easily suffer, in the immensity of space, several independent beings, each absolute master of its own portion, than two limited gods in this world, one confined to doing good, the other to doing evil. If God and matter both exist from eternity, "here are two necessary entities; and if there be two there may be thirty. We must confess our ignorance of the nature of divinity."
It is noticeable that, like most men on whom the idea of God does not take a very strong hold, Voltaire imagined powers in some respects superior to Deity. Thus he says above that nature can more easily suffer several independent gods than two opposed ones. Having supposed one or several gods to put the universe in order, he supposes an order anterior to the gods. This idea of a superior order, Fate, Necessity, or Nature, is a very old one. It is probably the protest of the human mind against those anthropomorphic conceptions of God, from which it is almost incapable of escaping. Voltaire and the Philosophers almost without exception believed that there was a system of natural law and justice connected with this superior order, taught to man by instinct. Sometimes in their system God was placed above this law, as its origin; sometimes, as we have seen, He was conceived as subjected to Nature. "God has given us a principle or universal reason," says Voltaire, "as He has given feathers to birds and fur to bears; and this principle is so lasting that it exists in spite of all the passions which combat it, in spite of the tyrants who would drown it in blood, in spite of the impostors who would annihilate it in superstition. Therefore the rudest nation always judges very well in the long run concerning the laws that govern it; because it feels that these laws either agree or disagree with the principles of pity and justice which are in its heart." Here we have something which seems like an innate idea of virtue. But we must not expect complete consistency of Voltaire. In another place he says, "Virtue and vice, moral good and evil, are in all countries that which is useful or injurious to society; and in all times and in all places he who sacrifices the most to the public is the man who will be called the most virtuous. Whence it appears that good actions are nothing else than actions from which we derive an advantage, and crimes are but actions that are against us. Virtue is the habit of doing the things which please mankind, and vice the habit of doing things which displease it. Liberty, he says elsewhere, is nothing but the power to do that which our wills necessarily require of us."[Footnote: Voltaire, xx. 439 (Siècle de Louis XIV., ch. xxxvii.), xxi. 369 (Louis XV.), xv. 34, 40, 123, 316 (Essai sur les moeurs), xliii. 74 (Examen important de Lord Bolingbroke), xxxi. 13 (Dict. philos. Liberté) xxxvii. 336 (Traité de métaphysique_). For general attacks on the Bible and the Jews, see (Oeuvres, xv. 123-127, xliii. 39-205, xxxix. 454-464. Morley's Diderot, ii. 178). Notice how many of the arguments that are still repeated nowadays concerning the Mosaic account of the creation, etc. etc., come from Voltaire. Notice also that Voltaire, while too incredulous of ancient writers, was too credulous of modern travelers.]