«Calcolar le stelle»: numero e irrazionale nella Grecia antica

Abstract

Historical assessments of the birth of scientific thought in Ionian natural philosophy – including works by scholars such as K. Popper, G. S. Kirk, E. R. Lloyd, and M. Sassi – have underestimated the importance of contemporary mathematical developments and the crisis brought about by the discovery of irrational magnitudes, perpetuating the idea that the rise of the scientific method based on observation coincided tout court with the emergence of critical rationality. Similarly, historians of philosophy and science have not fully appreciated the specific mental processes that enabled early Greek thinkers to achieve striking advances in cosmology and astronomy, such as Aristarchus’s heliocentric conception, nor have they satisfactorily explained why these advances were later repudiated in favor of the Ptolemaic system. Plato and Aristotle played a crucial role in the attempt to reframe the role of irrational thinking within the bounds of the rational and, in parallel, to advance a model of a finite, ordered universe governed by the perfection of circular motion.