however, to range the elements under the head of matter; for out of these as immanent parts they say substance is composed and moulded.[1]
From these facts we may sufficiently perceive the meaning of the ancients who said the elements of nature were more than one; but there are some who spoke of the universe as if it were one entity, though they were not all alike either in the excellence of their statement or in regard to the nature of the entity. The discussion of them is in no way appropriate to our present investigation of causes, for they do not, like some of the natural philosophers, assume being to be one and yet generate it out of the one as out of matter, but they speak in another way; those others add change, since they generate the universe, but these thinkers say the universe is unchangeable. Yet this much is appropriate to the present inquiry: Parmenides seems to fasten on that which is one in formula, Melissus on that which is one in matter, for which reason the former says that it is limited, the latter that it is unlimited[2]; while Xenophanes, the first of this school of monists (for Parmenides is said to have been his pupil), gave no clear statement, nor does he seem to have grasped either of these two kinds of unity, but he contemplates the whole heaven and says the One is, namely God. Now these thinkers, as we said, must be neglected for the purposes of the present inquiry—two of them entirely, as being a little too naïve, viz. Xenophanes and Melissus; but Parmenides seems to speak with somewhat more insight. For, claiming that, besides the existent, nothing non-existent exists, he thinks that the existent is of necessity one and that nothing else exists (on this we have spoken more clearly in our work on nature)[3], but being forced to follow the observed facts, and supposing the existence of that which is one in formula, but more than one according to our sensations, he now posits two causes and two principles, calling them hot and cold, i. e. fire and earth; and of these he ranges the hot with the existent, and the other with the non-existent.[4]
From what has been said, then, and from the wise men who
