Nicholas of Cusa

Nicholas was the son of a boat-owner on the Moselle. He studied law and theology at Heidelberg, Padua and Cologne, and in the 1430s took part in the Council of Basel as a canon lawyer, first supporting the council's supremacy over the pope and later moving to the papal side. In 1437 he sailed on an embassy to Constantinople, and on the voyage home the central insight of his thought came to him. He later became a cardinal and bishop of Brixen, where he fought the local duke for years and was once imprisoned.

On Learned Ignorance argues that finite intellect cannot grasp the infinite, just as a polygon never becomes a circle however many sides are added; yet to know this is the highest knowledge. God is the 'coincidence of opposites', in whom maximum and minimum, straight and curved, are one. The universe is God's finite manifestation, and since it has no fixed centre the earth is neither central nor at rest, nor are the heavenly bodies perfect spheres. This was a century before Copernicus.

His thought drew at once on Eckhart's mysticism, the negative theology of Pseudo-Dionysius, and mathematics. He wrote on squaring the circle, on calendar reform and on religious peace; On the Peace of Faith imagines representatives of every religion conversing in heaven and discovering that they worship the same God. Bruno, Kepler and Leibniz all learned from him, and Cassirer called him the first modern thinker.