Meister Eckhart is best known as a mystic, a preacher, and a theologian. William of Ockham, who probably learned of him when both men were under investigation at the papal court in Avignon in 1327, thought his views "fantastic, no less heretical than insane." Philosophers in the tradition of Ockham have continued to have doubts about Eckhart; those of other persuasions, such as Nicholas of Cusa in the fifteenth century, G. W. F. Hegel in the nineteenth, and Martin Heidegger in the twentieth, have found in Eckhart's thought a powerful philosophical resource and one of the most important speculative systems in Western thought.

Eckhart himself certainly thought that what he was engaged in teaching and preaching pertained to both philosophy and theology. Throughout his writings the German friar insists not only that revelation and reason cannot disagree (a position held by most Christian theologians) but also that one can...