‘The Aristippus of modern materialism’, La Mettrie made observations upon himself during an attack of fever; seeing a connection between the rapid circulation of blood and the operation of the mind, La Mettrie concluded that psychical phenomena were to be explained as the effects of organic changes in the brain and nervous system. The book caused an outcry and was seized by the police; La Mettrie was forced to return to Holland from Paris. In 1746 The Natural History of the Soul, together with Diderot's Philosophical Thoughts, was condemned by the Paris Parlement.

An attack on the medical profession

Published in Leiden for which the publisher Luzac was condemned by the religious authorities and translated in 1749 as Man a Machine. The work bears similarities in tone and content to Maupertius Venus physique, (1745). In the satirical dedication to Albrecht von Haller, La Mettrie assimiliated the pleasures of philosophy to sexual pleasure: speaking of the “sublime voluptuousness of study” he hints that he found it necessary to lead a life of sensual dissipation for the sake of finding philosophical truth.

Publication of first two volumes of La Mattrie's medical satire.