We shall leave these now and go on to Pythagoras, who was a contemporary of Anaximander; but the continuity of the development of the principle of physical philosophy necessitated our taking Anaximenes with him. We see that, as Aristotle said, they placed the first principle in a form of matter—in air and water first, and then, if we may so define Anaximander’s matter, in an essence finer than water and coarser than air. Heraclitus, of whom we have soon to speak, first called it fire. “But no one,” as Aristotle (Metaph. I. 8) remarks, “called earth the principle, because it appears to be the most complex element” (_διὰ τὴν μεγαλομέρειαν_); for it seems to be an aggregate of many units. Water, on the contrary, is the one, and it is transparent; it manifests in sensuous guise the form of unity with itself, and this is also so with air, fire, matter, &c. The principle has to be one, and hence must have inherent unity with itself; if it shows a manifold nature as does the earth, it is not one with itself, but manifold. This is what we have to say about the early Ionic Philosophy. The importance of these poor abstract thoughts lies (_a_) in the comprehension of a universal substance in everything, and (_b_) in the fact that it is formless, and not encumbered by sensuous ideas. No one recognized better the deficiencies in this philosophy than did Aristotle in the work already quoted. Two points appear in his criticism of these three modes of determining the absolute: “Those who maintain the original principle to be matter fall short in many ways. In the first place, they merely give the corporeal element and not the incorporeal, for there also is such.” In treating of nature in order to show its essence, it is necessary to deal with it in its entirety, and everything found in it must be considered. That is certainly but an empirical instance. Aristotle maintains the incorporeal to be a form of things opposed to the material, and indicates that the absolute must not be determined in a one-sided manner; because the principle of these philosophers is material only, they do not manifest the incorporeal side, nor is the object shown to be Notion. Matter is indeed itself immaterial as this reflection into consciousness; but such philosophers do not know that what they express is an existence of consciousness. Thus the first great defect here rests in the fact that the universal is expressed in a particular form.