The German philosopher Johann Georg Hamann (1730-1788) was known as the "Magus of the North." He held that truth is a matter of subjective belief, and he sought to reveal the divine in things and people.

Born on Aug. 27, 1730, in Königsberg, East Prussia, Johann Georg Hamann was the son of the local surgeon-barber and heir of generations of Protestant pastors, and this background helps explain his interests in science, medicine, and especially religion. The young Hamann was tutored at home, and the remarkable range of his intellectual pursuits was largely a product of self-education. He displayed an aptitude for languages and mastered Greek, Latin, French, Italian, English, and Hebrew in addition to his native German.

In 1746 Hamann enrolled at the University of Königsberg as a student of theology and later of law. There he was influenced by Martin Knutzen, the philosophy teacher of his...