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Thinkers

Julien Offray de La Mettrie

Enlightenment · Europe · 1709 to 1751

French doctor who held that humans are machines, and that thought depends closely on the body.

What it is

Julien Offray de La Mettrie (1709 to 1751) was a French physician and philosopher. He is remembered for the claim that the person is a kind of machine and that thought depends closely on the body, and for a book with that idea in its title.

He was born at Saint-Malo, studied medicine, and trained at Leiden under the physician Hermann Boerhaave. He served as a surgeon with the French military. His books caused such anger that he had to leave Paris, then Holland, and finally found shelter in Berlin, where he died in 1751.

The main ideas

  • Mind depends on body. When he fell ill he noticed how his own thinking changed with the state of his body. From this he concluded that mental processes follow from changes in the brain and nervous system.
  • The person as machine. In Man a Machine (1747) he put this materialist view more boldly and completely than before.
  • Mind as part of the body. He treated mental life as tied to bodily and organic change, a view that caused public outrage in his time.
  • Pleasure as the aim. He held that the point of life is pleasure. His Discourse on Happiness works out an ethics from his materialist principles.

What it looks like in practice

Picture someone who has slept badly for a week and finds that they cannot think clearly, feel patient, or even remember a conversation. La Mettrie would take that as plain evidence. The mind is not floating above the body but changes with it, and it is worth looking after the body in the same way as looking after the mind. This is an illustration of his line of reasoning, not a passage from his writing.

Books and moments

  • Natural History of the Soul (1745) set out these views. The outcry it caused forced him to leave Paris.
  • Man a Machine (1747) was published while he was in Holland. It is the work he is best known for, and it states his materialist and atheist views more boldly than his earlier books.
  • Discourse on Happiness works out the ethics of his view and puts pleasure at its centre.
  • Berlin, 1748. Frederick the Great gave him shelter and made him a court reader.

Questions and criticism

  • Can pleasure be the point of life? He thought so, and called pleasure of the senses the purpose of life.
  • How did he die? One account links his death to a feast followed by a stomach illness, and another to food poisoning. Both tie it to his reputation as a lover of pleasure, and the cause is not certain.

Close neighbours

The page on Baron d'Holbach shows another writer who held a materialist view, and the page on Epicurus shows an older school that made pleasure central.

Written by epchē in our own words, and checked against independent sources on 29 October 2026. The sources are listed below.

Who they connect to

Reacted against

  • René Descartes · He took Descartes' picture of animals as machines and applied it to human beings too.

Other Enlightenment thinkers

Sources we used

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