Along with the new view of the universe grew belief in the idea of a benign Providence, which could be trusted because it was visibly active in the world. Writers sought to express their sense of God’s benevolent intention as manifest in creation. To the Abbé Pluche domestic animals were not merely docile but naturally loved humanity. Voltaire, equally implausibly, observed of mountain ranges that they were “a chain of high and continuous aqueducts which, by their apertures allow the rivers and arms of the sea the space which they need to irrigate the land.” The idea of Providence could degenerate into the fatuous complacency that Voltaire himself was to deride and against which—in particular, the idea that the universe was just a vast theatre for the divine message—Samuel Taylor Coleridge was memorably to rebel. Faith, wrote the English poet, “could not be intellectually more evident without being morally less effective; without counteracting its own end by sacrificing the life of faith to the cold mechanism of a worthless because compulsory assent.” So the Enlightenment can be seen to be carrying the seeds of its own disintegration. The providential idea was based on unscientific assumptions in an age in which scientists, favoured by a truce with men of religion, were free to pursue researches that revealed an untidier, therefore less comforting, world. Newton had argued, from such problems as irregularities in the orbit of planets, that divine intervention was necessary to keep the solar system operating regularly. D’Alembert found, however, that such problems were self-correcting. From being the divine mechanic had God now become the divine spectator?
No less unsettling were the findings of geologists. Jean-Étienne Guettard concluded that the evidence of fossils found in the volcanic hills of the Puy de Dôme in south-central France conflicted with the time scheme of the Old Testament. Whether, like the count de Buffon, they attributed to matter a form of life, speculated about life as a constant, shapeless flux, or postulated a history of the world that had evolved over an immensely long time, scientists were dispensing with God as a necessary factor in their calculations. Some theologians sought compromise, while others retreated, looking to a separate world of intuitive understanding for the justification of faith. Joseph Butler pointed to conscience, the voice of God speaking to the human soul. He deplored the enthusiasm that characterized the tireless preaching of John Wesley and his message of the love of God manifested in Christ. “A true and living faith in God,” Butler declared, “is inseparable from a sense of pardon from all past and freedom from all present sins.” It was not the freedom understood by the philosophes, but it touched hearts and altered lives. Meanwhile the path of reason was open for the avowed atheism of Baron d’Holbach, who declared in his Système de la nature (1770; “The System of Nature”) that there was no divine purpose: “The whole cannot have an object for outside itself there is nothing towards which it can tend.” Another approach was taken by David Hume, author of Treatise on Human Nature (1739) and the Dialogues Concerning Natural Religion (1779). The notion of miracles was repugnant to reason, but he was content to leave religion as a mystery, to be a skeptic about skepticism, and to deny that man could reach objective knowledge of any kind.
These may appear to have been intellectual games for the few. It could only be a privileged, relatively leisured minority, even among the educated, who actively participated in debate or could even follow the reasoning. The impact was delayed; it was also uneven. In Dr. Johnson’s England the independence bestowed by the Anglican clergyman’s freehold and the willingness of the established church to countenance rational theology created a shock absorber in the form of the Broad Church. In Protestant countries criticism tended to be directed toward amending existing structures: there was a pious as well as an impious Enlightenment. Among Roman Catholic countries France’s situation was in some ways unique. Even there orthodox doctrines remained entrenched in such institutions as the Sorbonne; some bishops might be worldly but others were conscientious; monasteries decayed but parish life was vital and curés (parish priests) well trained. Nor was theology neglected: in 1770, French publishers brought out 70 books in defense of the faith. Of course the philosophes, endowed with the talents and the means to mount sustained campaigns, ensured that the question of religion remained high on the agenda. There was also a ready sale for writers who sought to apply the rational and experimental methods to what Hume was to call the science of man. Man and society
Chief among them was Charles de Secondat de Montesquieu. His presidency in the parlement of Bordeaux supported the career of a litterateur, scholarly but shrewd in judgment of men and issues. In the Persian Letters (1721), he had used the supposed correspondence of a Persian visitor to Paris to satirize both the church (under that “magician” the pope) and the society upon which it appeared to impose so fraudulently. His masterpiece, The Spirit of Laws, appeared in 22 editions within 18 months of publication in 1748. For this historically minded lawyer, laws were not abstract rules but were necessary relationships derived from nature. Accepting completely Locke’s sensationalist psychology, he pursued the line of the Sicilian Giambattista Vico, the innovative author of The New Science (1725), toward the idea that human values are the evolving product of society itself. Among social factors, he listed climate, religion, laws, the principles of government, the example of the past, and social practices and manners and concluded that from these a general spirit is formed. Montesquieu’s concern with knowledge as a factor in shaping society is characteristic of the Enlightenment. Nor was he alone in his Anglophile tendency, though it did not prevent him from misinterpreting the English constitution as being based on the separation of powers. The idea that moral freedom could be realized only in a regime whose laws were enacted by an elected legislature, administered by a separate executive, and enforced by an independent judiciary was to be more influential in the New World than in the Old. His theories reflected a Newtonian view of the static equilibrium of forces and were influenced by his perception of the French government as increasingly arbitrary and centralist; they were conceived as much as a safeguard against despotism as an instrument of progress.
Montesquieu’s political conservatism belonged to a world different from that of the younger generation of philosophes, for whom the main obstacle to progress was privilege; they put their trust in “the enlightened autocrat” and in his mandate for social engineering. They might fear, like Claude Helvétius, that his theories would please the aristocracy. Helvétius—a financier, amateur philosopher, and author of the influential De l’esprit (1759; “On the Mind”)—advocated enlightened self-interest in a way that found an echo in physiocratic economic theory and argued that each individual, in seeking his own good, contributed to the general good. Laws, being man-made, should be changed so as to be more useful. The spirit of the Enlightenment is well conveyed by his suggestion that experimental ethics should be constructed in the same way as experimental physics. By contrast, Montesquieu, whose special concern was the sanctity of human law, saw the problem of right conduct as one of adapting to circumstances. The function of reason was to bring about accord between human and natural law. While the objective nature of his inquiry encouraged those who trusted in the power of reason to solve human problems, it was left to those who saw the Enlightenment in more positive terms to work for change.