This book explores the changing perspective of astrology from the Middle Ages to the Early
Modern Era. It introduces a framework for understanding both its former centrality and its
later removal from legitimate knowledge and practice. The discussion reconstructs the changing
roles of astrology in Western science theology and culture from 1250 to 1500.The author
considers both the how and the why. He analyzes and integrates a broad range of sources. This
analysis shows that the history of astrology-in particular the story of the protracted
criticism and ultimate removal of astrology from the realm of legitimate knowledge and
practice-is crucial for fully understanding the transition from premodern
Aristotelian-Ptolemaic natural philosophy to modern Newtonian science.This removal the author
argues was neither obvious nor unproblematic. Astrology was not some sort of magical nebulous
hodge-podge of beliefs. Rather astrology emerged in the 13th century as a richly mathematical
system that served to integrate astronomy and natural philosophy precisely the aim of the New
Science of the 17th century. As such it becomes a fundamentally important historical question
to determine why this promising astrological synthesis was rejected in favor of a rather
different mathematical natural philosophy-and one with a very different causal structure than
Aristotle's.
