Auguste Comte

Comte was born in Montpellier to a devout royalist family, renounced God at fourteen, entered the École Polytechnique at sixteen and was expelled in 1816 for joining a student protest. In 1817 he became secretary to the utopian socialist Saint-Simon, whose influence over the next seven years was profound and whom he never afterwards acknowledged, having quarrelled over the authorship of their writings. He lived in poverty all his life on private tutoring and a post as examiner.

In 1826 he began lecturing on positive philosophy in his lodgings to an audience that included Humboldt and the mathematician Poisson; after three lectures he broke down, was confined in an asylum, and threw himself into the Seine before being rescued. He then spent twelve years on the six-volume Course of Positive Philosophy, published from 1830 to 1842. It proposes the law of three stages: each branch of knowledge passes from a theological stage (explaining by gods) through a metaphysical stage (explaining by abstract essences) to a positive stage (seeking laws without asking about essences). The sciences form a hierarchy by complexity: mathematics, astronomy, physics, chemistry, biology and finally 'sociology', which he founded and named.

In 1844 he met Clotilde de Vaux, a young woman separated from her husband, and fell passionately in love; she died of tuberculosis the next year. This platonic love turned his philosophy: the System of Positive Polity established a 'Religion of Humanity' with Humanity as its object of worship, its own calendar, saints from Aristotle to Dante, sacraments and priesthood, with Comte as high priest. Early supporters such as Mill and Littré left him over it, and Huxley called it 'Catholicism minus Christianity'.

Yet his central claim proved lasting: knowledge can come only from observed phenomena and their laws, science is the only valid knowledge, and society can be studied scientifically like nature and rebuilt for order and progress. 'Order and Progress' still stands on the Brazilian flag. Mill, Spencer, Durkheim and the Vienna Circle all started from him, and positivism became the most powerful current of the later nineteenth century.