‘Science,’ wrote Ernst Cassirer in his Essay on Man, ‘begins with a quest for simplicity.’ Remarkably enough, tradition has preserved the name of the man who first undertook such a quest: the first scientist. He was Thales of Miletus (ca 624–545 b.c.), one of the Seven Wise Men of the ancient world and the founder of the great Ionian school of natural philosophy. He appears to have been the first to have found the courage to abandon traditional mythopoetic explanation and to try and account for natural phenomena in terms of natural forces. As Aristotle, incidentally, the last of the Ionian scientists, put it, Thales was the founder of the philosophy which asserts that ‘the principles which (are) of the nature of matter (are) the only principles of all things’ (Aristotle a).