“ Happiness is the end of mankind. “It would be useless and almost unjust to insist upon a man’s being virtuous if he cannot be so without being unhappy. So long as vice renders him happy, he should love vice.” ”

“ He attracted more attention, however, in the department of philosophy. In 1767 Christianisme dévoilé appeared, in which he attacked Christianity and religion as the source of all human evils. This was followed up by other works, and in 1770 by a still more open attack in his most famous book, Le Système de la nature, in which it is probable he was assisted by Diderot. Denying the existence of a deity, and refusing to admit as evidence all a priori arguments, Holbach saw in the universe nothing save matter in spontaneous movement. What men call their souls become extinct when the body dies. ”

“ The study of science was to bring human desires into line with their natural surroundings. Not less direct and trenchant are his attacks on political government, which, interpreted by the light of after events, sound like the first distant mutterings of revolution. Holbach exposed the logical consequences of the theories of the Encyclopaedists. Voltaire hastily seized his pen to refute the philosophy of the Système in the article “Dieu” in his Dictionnaire philosophique, while Frederick the Great also drew up an answer to it. ”