French visionary philosopher who was one of the leading exponents of illuminism, an 18th-century philosophical movement that attempted to refute the rationalistic philosophies prevalent in that period.

After practicing law for six months at Tours, Saint-Martin joined the army in 1765. Stationed at Bordeaux, he came under the influence of the Jewish mystic Martinez Pasqualis. He left the army in 1771 and began to propagate mysticism. After visiting England and Italy, he returned to France in 1788 and was introduced to the writings of the German mystic Jakob Boehme, under the influence of which he gradually broke loose from the influence of Martinez Pasqualis. He later came under the influence of the Swedish philosopher Emanuel Swedenborg.

His writings include: Des erreurs et de la vérité (1775; “Errors and the Truth”); L'Homme de désir (1790; “The Man of Desire”); Le Nouvel Homme (1792; “The New Man”); Considérations sur la Révolution Française (1795; “Considerations on the French Revolution”); Le Crocodile (1798; “The Crocodile”), an allegorical poem; L'Esprit des choses (1800; “The Spirit of Things”); and Le Ministère de l'homme-esprit (1802; The Ministry of Man and Spirit). He signed his works Le Philosophe Inconnu (“The Unknown Philosopher”).