The French philosopher René Descartes declared that all animals except humans are “machines,” very complicated automata, responding to external stimuli in a mechanical way. Humans alone, because they possess immaterial souls, are conscious and endowed with free will and therefore capable of being virtuous or sinful. However, Julien Offroy de La Mettrie denied the existence of any sharp distinction between humans and other animals. In his Histoire naturelle de l’âme (1745; Treatise on the Soul, 1996), he raised a strong objection to Descartes’s calling brutes “machines,” thereby denying that they think and feel. However, three years later, he changed his terminology (not his doctrine) and argued that animals are machines that feel, and so are humans. “The human body is a machine which winds its own springs; . . . the soul is but a principle of motion or a material and sensible part of the brain.” Man a Machine, the better-known translation of L’Homme-machine, is somewhat of a misnomer. Although in English it seems strange to call a man or a dog a machine, it makes sense to speak of them as mechanisms, which is what La Mettrie meant. Hence his philosophy is often referred to as mechanism.