But since the unqualified term ‘being’ has several meanings, of which one was seen’ to be the accidental, and another the true (’non-being’ being the false), while besides these there are the figures of predication (e.g. the ‘what’, quality, quantity, place, time, and any similar meanings which ‘being’ may have), and again besides all these there is that which ‘is’ potentially or actually:-since ‘being’ has many meanings, we must say regarding the accidental, that there can be no scientific treatment of it. This is confirmed by the fact that no science practical, productive, or theoretical troubles itself about it. For on the one hand he who produces a house does not produce all the attributes that come into being along with the house; for these are innumerable; the house that has been made may quite well be pleasant for some people, hurtful for some, and useful to others, and different-to put it shortly from all things that are; and the science of building does not aim at producing any of these attributes. And in the same way the geometer does not consider the attributes which attach thus to figures, nor whether ‘triangle’ is different from ‘triangle whose angles are equal to two right angles’.-And this happens naturally enough; for the accidental is practically a mere name. And so Plato was in a sense not wrong in ranking sophistic as dealing with that which is not. For the arguments of the sophists deal, we may say, above all with the accidental; e.g. the question whether ‘musical’ and ‘lettered’ are different or the same, and whether ‘musical Coriscus’ and ‘Coriscus’ are the same, and whether ‘everything which is, but is not eternal, has come to be’, with the paradoxical conclusion that if one who was musical has come to be lettered, he must also have been lettered and have come to be musical, and all the other arguments of this sort; the accidental is obviously akin to non-being. And this is clear also from arguments such as the following: things which are in another sense come into being and pass out of being by a process, but things which are accidentally do not. But still we must, as far as we can, say further, regarding the accidental, what its nature is and from what cause it proceeds; for it will perhaps at the same time become clear why there is no science of it.

Since, among things which are, some are always in the same state and are of necessity (not necessity in the sense of compulsion but that which we assert of things because they cannot be otherwise), and some are not of necessity nor always, but for the most part, this............