What... was the step that placed the Ionian cosmologists... above the [] level of the Maoris? ...[T]he real advance made by the scientific men of Miletos was that they left off telling tales. They gave up the hopeless task of describing what was, when as yet there was nothing, and asked instead what all things really are now.The great principle which underlies all their thinking, though it is first put into words by Parmenides, is that Nothing comes into being out of nothing, and nothing passes away into nothing. They saw, however, that particular things were always coming into being and passing away again, and from this it followed that their existence was no true or stable one. The only things that were real and eternal were the original matter which passed through all these changes and the motion which gave rise to them, to which was... added that law of proportion or compensation...