Is astrology universal? Early modern globalization and the disruption of traditional knowledge.

The maritime expansion of the early modern period and the discovery of new continents necessitated a profound revision in traditional cosmology, bringing into question the millennia-old practices that were framed around that cosmology. Among these practices was astrology, which in the early modern period reached an unprecedented level of popularity through the development of the printing press. The application of the astrological corpus in tropical and southern latitudes questioned many of the foundational Ptolemaic concepts. At the core of this problem was the reversal of the seasons in the southern hemisphere. Since Ptolemy had firmly grounded the natural explanation of astrological attributes of the zodiac and the planets on the seasonal qualities, their reversal would imply a complete change in the zodiacal and planetary properties. Authors such as Girolamo Cardano, Tommaso Campanella and Athanasius Kircher addressed this matter, but it never became a central point of debate in the astrological literature of the period. However, practitioners in the New World, whose empirical view was very different to that of European authors, reached different conclusions. This problem offers an example of the difficulty in reconciling traditional authority with new knowledge. At the same time, it exposes the sharp contrast between the theoretical perspective of Europe-based authors and the actual experience of astrologers practising in the New World.