[Sidenote: Anaximenes asserts that air is the first principle.]
But it is not alone the water or ocean that seems to be infinite, and capable of furnishing a supply for the origin of all other things. The air, also, appears to reach as far as the stars. On it, as Anaximenes of Miletus remarks, "the very earth itself floats like a broad leaf." Accordingly, this Ionian, stimulated doubtless by the hope of sharing in or succeeding to the celebrity that Thales had enjoyed for a century, proposed to substitute for water, as the primitive source of things, atmospheric air. And, in truth, there seem to be reasons for bestowing upon it such a pre-eminence. To those who have not looked closely into the matter, it would appear that water itself is generated from it, as when clouds are formed, and from them rain-drops, and springs, and fountains, and rivers, and even the sea. He also attributes infinity to it, a dogma scarcely requiring any exercise of the imagination, but being rather the expression of an ostensible fact; for who, when he looks upward, can discern the boundary of the atmosphere. Anaximenes also held that even the human soul itself is nothing but air, since life consists in inhaling and exhaling it, and ceases as soon as that process stops. He taught also that warmth and cold arise from mere rarefaction and condensation, and gave as a proof the fact that when we breathe with the lips drawn together the air is cold, but it becomes warm when we breathe through the widely-opened mouth. Hence he concluded that, with a sufficient rarefaction, air might turn into fire, and that this probably was the origin of the sun and stars, blazing comets, and other meteors; but if by chance it should undergo condensation, it would turn into wind and clouds, or, if that operation should be still more increased, into water, snow, hail, and, at last, even into earth itself. And since it is seen from the results of breathing that the air is a life-giving principle to man, nay, even is actually his soul, it would appear to be a just inference that the infinite air is God and that the gods and goddesses have sprung from it.
Such was the philosophy of Anaximenes. It was the beginning of that stimulation of activity by rival schools which played so distinguished a part in the Greek intellectual movement. Its superiority over the doctrine of Thales evidently consists in this, that it not only assigns a primitive substance, but even undertakes to show by observation and experiment how others arise from it, and transformations occur. As to the discovery of the obliquity of the ecliptic by the aid of a gnomon attributed to Anaximenes, it was merely a boast of his vainglorious countrymen, and altogether beyond the scientific grasp of one who had no more exact idea of the nature of the earth than that it was "like a broad leaf floating in the air."