Though philosophers nowadays do not spend a lot of time thinking about astrology, in the history of philosophy it is a major topic whose importance is generally underestimated. Astrology was endorsed and even practiced by some philosophers, including ‘the Philosopher of the Arabs’ al-Kindī, while other philosophers like Augustine or al-Fārābī were harshly critical of this science. Still others took a middle ground, for instance by saying that astrology might be possible in principle but not in practice, or by arguing that astrological influence is real but leaves space for free will. In this talk an overview will be given of the main philosophical themes that emerge from discussions of astrology in late antiquity and the medieval period, in both the Latin Christian and Islamic spheres: determinism and freedom, the question of how heavenly causation works and how it relates to divine providence, and the epistemic status of this science (and whether it is a science at all). We will also discuss the way that astrology served as a vector for the transmission of ideas across linguistic and cultural boundaries.
