The new star of 1572 and the comet of 1577 had a major impact on the ways in which astronomical research developed in the late sixteenth and early seventeenth centuries. Behind this gradual but significant change there was an extended epistemological reform which placed increasing emphasis on reason and experience and strove to exclude arguments from Scripture and authority from scientific debate. This paper argues that the humanist debate on astrology after 1577, which was initiated by highly prestigious members of (...) a supraconfessional Republic of Letters, can be seen as an element of this process. Unlike earlier detractors of astrology, these new critics chiefly employed philosophical and scientific arguments concerning the legitimation of the entire art. By analysing a variety of accounts, this paper will reveal how great and complex the stakes in the debate over astrology were. They concerned not only the crucial problem of predestination and God’s interventionalism (hence also the possibility of miracles), but also the idea of science, the concept of the human mind, and ultimately the humanist ideal of the virtuous, rational, and responsible citizen. (shrink)

ArgumentThe subject of the paper is the shift from an astrology-oriented astronomy towards an allegedly more objective, mathematically grounded approach to astronomy. This shift is illustrated through a close reading of Tycho Brahe's scientific development and the contemporaneous changes in his communicational strategies. Basing the argument on a substantial array of original sources it is claimed that the Danish astronomer developed a new astronomical discourse in pursuit of credibility, giving priority to observational astronomy and natural philosophical questions. The abandonment of (...) astrology in public discourse is primarily explained by Tycho's social position and greater sensibility to controversial issues. Tycho's example suggests that the changes in rhetorical strategies regarding astrology (which happened earlier than changes in astrological belief) should be given more recognition in the history of astronomy. (shrink)