In Search of the True Nature of the Rainbow: Renewal of the Aristotelian Tradition in the Renaissance and the De Iride1

Abstract

From the point of view of the history of science the discussion about how the rainbow is formed is one of the most interesting sections of Aristotle’s philosophy of nature (Meteorologica, Book 3, Chapter 4). This chapter clearly shows that for Aristotle the explanation of a natural phenomenon cannot be reduced to its mathematical formulation but must consider the whole of the changes that take place during its production. In this case, Aristotle acknowledged the need to resort to mathematics in order to single out the cause of the rainbow. Therefore, he did not hesitate to make use of the results obtained by the contemporaneous science of optics, but he also had to go beyond them since one of the essential aspects of the phenomenon, colour, seemed to have been almost ignored in the exact mathematical studies made by the scientists of that time.