La Mettrie’s first career was as a doctor, and he served from 1743 to 1745 as surgeon in the army during the War of the Austrian Succession. In 1745 he published Histoire naturelle de l’âme (‘The Natural History of the Soul’) whose materialistic tendencies caused enough uproar for La Mettrie to retreat to Holland. Unabashed however, in 1748 he produced his most influential work, L’Homme machine (trs. as Man a machine, 1749), whose atheism and materialism outraged even the Dutch. Frederick the Great of Prussia invited La Mettrie to Berlin, where he continued to offend pious and dualistic orthodoxy with L’Homme plante (1748), Le Système d’Epicure (1750), and Discours sur le bonheur (1750). Although his opinions were scandalous, when La Mettrie died prematurely (according to his enemies, because of hedonistic over-indulgence), Frederick composed his eulogy. La Mettrie’s materialism is firmly based on the physics, chemistry, anatomy, and physiology of his time. But his forceful advocacy of the dependence of mental function on the state of the central nervous system and brain, and his resolutely scientific approach to the dynamics of motion and motivation, make him the earliest committed example of what is now the dominant functionalist and physicalist biomedical approach to the nature of human beings. In ethics La Mettrie saw happiness as the natural aim of each organism (akin to health), and a century before Nietzsche drew the corollary that the bad conscience, as a prime enemy of happiness, is merely a disease that needs a cure.