Summary

Martin Luther was not an original contributor to the study of cosmology, and if one were to judge only by his explicit remarks on the matter, it would seem to have been of little interest to him. He was, however, every bit a man of his times, and as such he assumed what educated people of his times assumed, including in the matter of the nature and structure of reality. The world in which he came of age was informed by a compelling vision of the universe as a whole. Astronomical observation and mathematical calculation in the traditions of Aristotle and Ptolemy had long since combined with philosophical and religious speculation to render Luther’s world a coherent “cosmos” (Gk. kosmos, “order” or “world”), at the center of which reposed a stationary sphere, the earth. This world was surrounded at ever-increasing heights by the heavenly spheres, each of them thought to be wheeling in at tremendous rates of speed that increased as one moved up through their heights: first the moon, then the planets, the stars, and ultimately the prime mover. This long-traditional view of the cosmos rendered reality itself an arena of intense motion and beauty.

Taken in a broad scientific and aesthetic sense, cosmology provided not only an interpretation of the heavens but also an imaginative lens through which to experience and understand one’s self and one’s world. Though he quibbled over some of the details, Luther clearly viewed himself and his world through that very lens. During his university studies in Erfurt for the bachelor and master of arts degrees, he read cosmology as a subject covered in the integrated approach to learning set forth in a curriculum based on the trivium (grammar, rhetoric, and dialectic) and quadrivium (arithmetic, geometry, astronomy, and music). In combination with other later medieval notions—such as the understanding of the human body and its four humors or the sublunar sphere and its four constituent elements (earth, water, air, fire)—cosmology became for Luther what it was for all his educated peers, that is, a world view. Thus, while Luther was not a cosmologist per se, the Aristotelian-Ptolemaic cosmos provided a set of background beliefs that informed his theology and world view at every level. He also developed a distinctive understanding of the reality and exercise of power and authority, both on the earth and in the heavens.