Anaximenes (fl. 548 B.C.), yet another Milesian, pupil or at least follower in turn of Anaximandros, speculates similarly, making his infinite and first principle the air, in which he conceives the earth to be suspended; theorizes on the rainbow, earthquakes, the nature and the revolution of the heavenly bodies (which, with the earth, he supposed to be broad and flat); and affirms the eternity of motion and the perishableness of the earth. [487] The Ionian thought of the time seems thus to have been thoroughly absorbed in problems of natural origins, and only in that connection to have been concerned with the problems of religion. No dogma of divine creation blocked the way: the trouble was levity of hypothesis or assent. Thales, following a Semitic lead, places the source of all things in water. Anaximandros, perhaps following another, but seeking a more abstract idea, posited an infinite, the source of all things; and Anaximenes in turn reduces that infinite to the air, as being the least material of things. He cannot have anticipated the chemical conception of the reduction of all solids to gases: the thesis was framed either à priori or in adaptation of priestly claims for the deities of the elements; and others were to follow with the guesses of earth and fire and heat and cold. Still, the speculation is that of bold and far-grasping thinkers, and for these there can have been no validity in the ordinary God-ideas of polytheism. There is reason to think that these early "schools" of thought were really constituted by men in some way banded together, [488] thus supporting each other against the conservatism of religious ignorance. The physicians were so organized; the disciples of Pythagoras followed the same course; and in later Greece we shall find the different philosophic sects formed into societies or corporations. The first model was probably that of the priestly corporation; and in a world in which many cults were chronically disendowed it may well have been that the leisured old priesthoods, philosophizing as we have seen those of India and Egypt and Mesopotamia doing, played a primary part in initiating the work of rational secular thought.