Page:Metaphysics by Aristotle Ross 1908 (deannotated).djvu/78

1003b in these cases means the same thing, and unity is nothing apart from being ; and if, further, the essence of each thing is one in no merely accidental way, and similarly is from its very nature something that is:—all this being so, there must be exactly as many species of being as of unity. And to investigate the essence of these is the work of a science which is generically one—I mean, for instance, the discussion of the same and the similar and the other concepts of this sort; and nearly all contraries are reducible to this source; but let us take them as having been investigated in the 'Selection of Contraries' .—And there are as many parts of philosophy as there are kinds of substance, so that there must necessarily be among them a first philosophy and one which follows this. For being and unity fall immediately into genera; and therefore the sciences too will correspond to these genera. For 'philosopher' is like 'mathematician' with its variety of meanings; for mathematics also has parts, and there is a first and a second science and other successive ones within the sphere of mathematics. Now since it is the work of one science to investigate opposites, and plurality is opposite to unity, and it belongs to one science to investigate the negation and the privation because in both cases we are really investigating unity, to which the negation or the privation refers (for we either say simply that unity is not present, or that it is not present in some particular class; in the latter case the characteristic difference of the class modifies the meaning of 'unity', as compared with the meaning conveyed in the bare negation; for the negation means just the absence of unity, while in privation there is also implied an underlying nature of which the privation is predicated ),—since, then, plurality is opposite to unity, in view of all these facts, the contraries of the concepts