When, in 1729, Montesquieu and Voltaire returned to France from England, and introduced among their fellow-countrymen the ideas prevalent among the English deists and empiricists, an impetus was given to a French empirical movement which, with characteristic disregard for the restraints of convention and positive religion, advanced from psychological empiricism to materialism in metaphysics, hedonism in ethics, and unbelief and revolt in matters of religious conviction. The social, political, and religious conditions of France in the eighteenth century contributed to this result. The court of Versailles had become a synonym for frivolity if not for licentiousness, and even after due allowance is made for the exaggerations of historians prejudiced against the old régime, it must be admitted that the grievances of the subjects of the monarchy were many and serious. The Church, whose duty it was to inculcate justice and forbearance, was identified, in the minds of the people, with the monarchy which they feared and detested. Thus it was that the poets, philosophers, and essayists of the latter half of the eighteenth century found in the popular mind a field ready to receive the seeds of the materialism and naturalism which flourished in the days preceding the Revolution and bore fruit in the Revolution itself. In England the old order gradually yielded to the action of the new forces; in France the old order maintained an attitude of unyielding antagonism. In England the establishment of new political ideas was in the nature of a slow assimilation; in France the destruction of the ancient political system assumed the proportions of a cataclysm.
Speculative Sensism. The first to formulate a thoroughgoing system of sensism, as a logical development of Locke's empiricism, was the Abbé Condillac (1715-1780) In his Traité des sensations he reduces all knowledge to experience and all experience to sensations. In fact, consciousness with all its contents is nothing but transformed sensations (sensations transformées). To illustrate this, Condillac imagines a statue which is first endowed with the sense of smell, and then with other senses in succession, the sense of touch being last; for it is by means of the sense of resistance that we distinguish between self and not-self. Before being endowed with the sense of touch the statue refers odor, color, and so forth, to itself; after it has acquired the sense of touch, it refers its sensations to the external world. Personality is, therefore, the sum of our sensations. Condillac teaches that it is by the superiority of the sense of touch that man differs from brutes: that every sensation is accompanied by pleasure or pain; that desire springs from the remembrance of pleasant sensations; that the "good" as well as the "beautiful" denotes a pleasure-giving quality.
With Condillac is associated Charles Bonnet (1720-1793), who in his Essai de psychologie advocates a mitigated form of sensationalism.
Ethical Sensism. The ethical deductions from sensistic psychology appear in the writings of Helvétius (1715-1771), author of De l'esprit and De l'homme. Helvétius teaches that all men are equally endowed by nature, that the difference between men arises from education, and that susceptibility to pleasure and pain, which declares itself in self-interest, is the ultimate element in human character, and the source of all mental and moral activity. Education, legislation, and positive religion are doomed to failure as long as they refuse to recognize the truth that all that is good and noble and virtuous in human conduct is based on self-interest.
Sceptics and Materialists. Voltaire (1694-1778), although not a professed philosopher, exercised a widespread influence on the philosophic thought of his century. His Dictionnaire philosophique portatif was written for the purpose of ridding philosophy of cumbersome technical terminology and presenting it in popular form. This necessitated superficiality of treatment, but, as Erdmann says, in Voltaire's superficiality lies his strength. Voltaire was not an atheist: not only did he believe that the existence of God is proclaimed by all nature, but he was even of opinion that if God did not exist we should be under the necessity of inventing a God. He defended immortality on the ground of practical necessity, and openly declared that materialism is nonsense. It was characteristic of the superficiality of the man that the earthquake of Lisbon (1775) should change him from an optimist to a pessimist. He attacked Christianity as a positive form of religion, waging unwearied war against the Scriptures, the Church, and the most sacred beliefs of Christians. In this way, by helping to undermine belief in the supernatural, he aided the cause of materialism and atheism.
Materialism and atheism were openly taught and defended in the famous Encyclopedia (Dictionnaire raisonné des arts des sciences et des métiers), which was published at Paris between the years 1751 and 1772. The principal encyclopedists were Diderot, d'Alembert, Voltaire, Holbach, and Rousseau. The work was sceptical, irreverent, and brilliant with keen wit and caustic satire. It was by the charms of its style, rather than by the force of its arguments, that it did so much towards sapping the popular belief in God, in spirituality, in human liberty, and in the sacredness of the traditional ideals of morality.
The physician La Mettrie (1709-1751), author of L'histoire naturelle de l'âme and L'homme machine, was one of the most outspoken defenders of materialism. He taught that everything spiritual is a delusion, and that physical enjoyment is the highest aim of human action. The soul, he maintained, is nothing but a name, unless by it we mean the brain, which is the organ of thought; thought is the function of the brain; man excels brutes simply because his brain is more highly developed; death ends all things, and consequently we should enjoy this world and hasten the reign of atheism, for men will never be truly happy until theologians will have ceased to trouble and Nature will have asserted her claims.
The materialistic monism thus flippantly defended by La Mettrie was taught with more pretension to scientific seriousness in the work entitled Système de la nature, which was published pseudonymously in 1770, and of which Holbach (1723-1789) is now universally admitted to be the author. The work may be said to be the bible of the materialists of the end of the eighteenth century.
The last representative of psychological materialism in the eighteenth century was the physician Cabanis (1757-1808), who taught that body and mind are identical, that the nerves are the man, and that thought is a secretion of the brain: "Le cerveau digère les impressions . . . il fait organiquement la sécrétion de la pensée."{1}
Political Philosophers. It was Montesquieu (1689-1755), author of De l'esprit des lois, who first introduced Locke's empiricism into France. In his Lettres persanes he had shown himself an ardent admirer of the federal form of government, but in the work De l'esprit des lois, written after his return from England, he holds up the English constitutional monarchy as the ideal of political organization. He contends that right is anterior to law, advocates the independence of the judicial power with respect to the executive and legislative powers, and defends the extension of the legislative authority of representative assemblies. He teaches that laws should be adapted to the character and spirit of the nation, and, following the empirical method, he traces the influence of climate, manners, religion, etc., on national character
Jean Jacques Rousseau{2} (1712-1778) was, in one respect, the most consistent representative of the movement which we have been studying, -- a movement to establish the individualistic point of view in religion, philosophy, and politics, -- yet, in another respect, he was a most uncompromising antagonist of that movement; for, instead of insisting on the advantages of enlightenment and civilization he advocated a return to primitive feeling and to the state of nature. Émile, a philosophical romance, is devoted to an account of his ideal of education, and the treatise entitled Contrat social, to an exposition of his political philosophy. He draws an ideal picture of man, as he originally existed in the state of nature, before entering into the social contract by which society was first formed, and he teaches that all authority resides in the sovereign will of the people. He maintains the right of the people to assemble for the purpose of confirming, altering, and abrogating all authority in the state. Thus he rejects the division of legislative, judicial, and executive powers, substituting for them the rule of popular assembly. In his religious doctrines he is a deist rather than an atheist.
Historical Position. The so-called French enlightenment of the eighteenth century is a one-sided development of the empiricism inaugurated in England by Locke and introduced into France by Montesquieu and Voltaire. If we except Rousseau, the representatives of the age of enlightenment were men of meager or at most of mediocre intellectual ability, who failed to leave any lasting impression on the development of speculative thought. Indeed, Voltaire, who certainly knew the age in which he lived, pronounced it to be "an age of trivialities." Rousseau alone spoke as one who had seriously studied the spirit of his time, when he demanded the abandonment of artificial culture and conventional refinement in favor of what is natural, simple, and therefore of permanent value in human life. To this cry of an age of unrest the French Revolution was the answer.
{1} Rapports du physique et du morale de l'homme (cf. Dictionnaire des sciences philosophiques art., "Cabanis").
{2} Consult Morley, Rousseau (London, 1873).