The Age of Enlightenment in Europe was formed in special historical conditions. These were the reign of the absolute monarchy in France, which was experiencing a crisis and the gap between economic development and the system of power, as well as the tightening of clericalism (the Nantes Edict of Tolerance was repealed). The sources of new ideas were the scientific picture of the world developed by Newton, as well as English social philosophy (John Locke, the philosophy of “common sense”) and French free-thinking writers and thinkers such as Pierre Beil, Descartes and Montesquieu.
The ideas of the Enlightenment, first of all, made the problem of the opposition of Reason and Faith the most important philosophical question and put forward the cult of Reason and Progress as one of the main goals of mankind. If the English philosophers, to whom the term "enlightenment" itself belongs, were theorists of the so-called cabinet character, the French enlighteners represented a real social movement, or "party" of philosophers. They were fond of politics, had access to the general public and wrote in French, understandable to those who were literate. The main principle of the French Enlightenment was the conviction that ideas prevailed over society. They believed that ideas influence the development of society, and in order to enlighten society, it is first of all necessary to educate people.
The philosophy of Enlightenment is inconceivable without such, certainly, its most vivid representative, as François Voltaire. True, he did not create his own philosophical system, but was famous as a fighter against fanaticism and superstition, not without reason his famous cry against the dominance of clericalism of the Roman Catholic Church "Crush the reptile!" survived the centuries. Voltaire was a deist in his views, he believed that the existence of Reason in the Universe proves the reason and purpose of this existence. He also opposed atheism, believing that the rejection of God would hit the moral foundations of humanity. Voltaire tried to popularize Newton's doctrine of the laws of nature in France, and also criticized the theory of "innate ideas" of Descartes and Berkeley solipsism. In the theory of knowledge, Voltaire relied on Locke and Francis Bacon: knowledge is based on experience, but there are also absolute knowledge, such as mathematics, morality, and the concept of God. In the field of psychology, the philosopher shared the then fashionable teaching that man is a rational mechanism without a soul, but with instinct and intelligence.
The second unconditional authority created by the philosophy of the Enlightenment, and the opponent of Voltaire, is Jean-Jacques Rousseau. His most famous works are considered “Reflections on the origin of inequality between people”, “Social contract” and “New Eloise”. Rousseau believed that the main driving force in man is not the mind, but feelings, instincts such as conscience and Genius. Rousseau criticized modern science and industry, assuring them that they separate man from nature, creating artificial needs for him and alienating people from each other. The task of philosophy is to bridge this gap and make a person happy. In the field of history, Rousseau shared the idea of a "golden age" destroyed by private property. It’s impossible to go back, of course, but you can at least partially correct the situation by concluding a social contract and creating communities of equal small owners who resolve all issues through a referendum. Rousseau was also a theoretician of "natural education" in the lap of nature without a restrictive framework, and religiously adhered to the ideas of personal experience.
The philosophy of Enlightenment is also represented by a galaxy of French materialists - Lametri, Helvetius, Holbach, Didro. Holbach in the "System of Nature" reduced all phenomena to the movement of material particles, and Lametri connected matter not only with movement, but also with feelings, suggesting the presence of automatism in psychology ("Man is a machine"). They also supported the idea of developing a person from an inorganic "kingdom" through the plant and animal. One of the distinguishing features of French materialism of this era is its determinism: everything obeys universal laws, there is no chance, no purpose, but only cause and effect. Cognition, in their opinion, comes from experience, is transformed into thinking, and its purpose is to perfect a person. But the basic condition for knowledge is the sensations with which we "register" the world around us. However, for example, Didro, unlike La Mettrie, believed that a person in such a system resembles, rather, not a car, but a piano, since he uses such a system of signs as language (and the signs correspond to the keys of the piano). In social philosophy, materialists adhered to the views on rational egoism, which can cooperate on common interests and thus come to universal interest and morality.
Since almost all the famous philosophers that the Enlightenment philosophy gave the world agreed among themselves that common sense and the right ideas form the right social system, they created the Encyclopedia project, the main ideologist and administrator of which was Didro. He managed to bring together all the enlighteners, both materialists and deists, so that they write articles about all scientific achievements in both the natural and humanitarian fields, combine progressive views with criticism of the obsolete and give a picture of the human mind as a whole. This work began with great enthusiasm, but then most of the participants left the project for both financial and internal reasons. Left alone, Diderot was able to complete this work and publish all 52 volumes of the Encyclopedia, summarizing everything that science of the XVII-XVIII centuries achieved.