_Ibid._ i. 3; 186 a 4. To those proceeding after this impossible manner things seem to be one, and it is not difficult to refute them from their own statements. For both of them reason in a fallacious manner, both Parmenides and Melissos; for they make false assumptions, and at the same time their course of reasoning is not logical.... And the same sort of arguments are used by Parmenides, although he has some others of his own, and the refutation consists in showing both that he makes mistakes of fact and that he does not draw his conclusions correctly. He makes a mistake in assuming that being is to be spoken of absolutely, speaking of it thus many times; and he draws the false conclusion that, in case only whites are considered, white meaning one thing, none the less there are many whites and not one; since neither in the succession of things nor in the argument will whiteness be one. For what is predicated of white will not be the same as what is predicated of the object which is white, and nothing except white will be separated from the object; since there is no other ground of separation except the fact that the white is different from the object in which the white exists. But Parmenides had not yet arrived at the knowledge of this. _Ibid._ i. 5; 188 a 20. Parmenides also makes heat and cold first principles; and he calls them fire and earth. _Ibid._ iii. 6; 207 a 15. Wherefore we must regard Parmenides as a more acute thinker than Melissos, for the latter says that the infinite is the all, but the former asserts that the all is limited, equally distant from the centre [on every side].[61] _Gen. Corr._ i. 3; 318 b 6. Parmenides says that the two exist, both being and not being—_i.e._ earth and water. _Metaph._ i. 3; 984 b 1. None of those who have affirmed that the all is one have, it happens, seen the nature of such a cause clearly, except, perhaps, Parmenides, and he in so far as he sometimes asserts that there is not one cause alone, but two causes.