But the difference between Melissus and his master can hardly be said to be a difference of doctrine; point for point, they are identical. The difference is a difference of vision or mental picture as to this mighty All which is One. Melissus, so to speak, places himself at the centre of this Universal being, and sees it stretching out infinitely, unendingly, in space and in time. Its oneness comes to him as the _sum_ of these infinities. Parmenides, on the other hand, sees all these endless immensities as related to a centre; he, so to speak, enfolds them all in the grasp of his unifying thought, and as thus equally and necessarily related to a central unity he pronounces the All a sphere, and therefore limited. The two doctrines, antithetical in terms, are identical in fact. The absolutely unlimited and the absolutely self-limited are only two ways of saying the same thing. This difference of view or vision Aristotle in the passage quoted expresses as a difference between _thought_ ((Greek) _logos_) and _matter_ ((Greek) _hule_). This is just a form of his own radical distinction between Essence and Difference, Form and Matter, of which much will be said later on. It is like the difference {49} between Deduction and Induction; in the first you start from the universal and see within it the particulars; in the second you start from the particulars and gather them into completeness and reality in a universal. The substance remains the same, only the point of view is different. To put the matter in modern mathematical form, one might say, The universe is to be conceived as a _sphere_ (Parmenides) of _infinite radius_ (Melissus). Aristotle is not blaming Melissus or praising Parmenides. As for Xenophanes, Aristotle after his manner finds in him the potentiality of both. He is prior both to the process of thought from universal to particular, and to that from particular to universal. He does not argue at all; his function is Intuition. "He looks out on the mighty sky, and says, The One is God."