Aristotle (384-322 BC)

Physics

Translated by R. P. Hardie and R. K. Gaye

Book I

Chapter 3

If, then, we approach the thesis in this way it seems impossible for all things to be one. Further, the arguments they use to prove their position are not difficult to expose. For both of them reason contentiously—I mean both Melissus and Parmenides. [Their premisses are false and their conclusions do not follow. Or rather the argument of Melissus is gross and palpable and offers no difficulty at all: admit one ridiculous proposition and the rest follows—a simple enough proceeding.]

The fallacy of Melissus is obvious. For he supposes that the assumption ‘what has come into being always has a beginning’ justifies the assumption ‘what has not come into being has no beginning.’ Then this also is absurd, that in every case there should be a beginning of the thing—not of the time and not only in the case of coming to be in the full sense but also in the case of coming to have a quality—as if change never took place suddenly. Again, does it follow that being, if one, is motionless? Why should it not move, the whole of it within itself, as parts of it do which are unities, e.g. this water? Again, why is qualitative change impossible? But, further, being cannot be one in form, though it may be in what it is made of. (Even some of the physicists hold it to be one in the latter way, though not in the former.) Man obviously differs from horse in form, and contraries from each other.

The same kind of argument holds good against Parmenides also, besides any that may apply specially to his view: the answer to him being that this is not true and that does not follow. His assumption that one is used in a single sense only is false, because it is used in several. His conclusion does not follow, because if we take only white things, and if ‘white’ has a single meaning, none the less what is white will be many and not one. For what is white will not be one either in the sense that it is continuous or in the sense that it must be defined in only one way. Whiteness will be different from what has whiteness. Nor does this mean that there is anything that can exist separately, over and above what is white. For whiteness and that which is white differ in definition, not in the sense that they are things which can exist apart from each other. But Parmenides had not come in sight of this distinction.

It is necessary for him, then, to assume not only that ‘being’ has the same meaning, of whatever it is predicated, but further that it means what just is and what is just one. It must be so, for an attribute is predicated of some subject, so that the subject to which being is attributed will not be, as it is something different from being. Something, therefore, which is not will be. Hence substance will not be a predicate of anything else. For the subject cannot be a being, unless being means several things, in such a way that each is something. But ex hypothesi being means only one thing.

If, then, substance is not attributed to anything, but other things are attributed to it, how does substance mean what is rather than what is not? For suppose that substance is also white. Since the definition of the latter is different (for being cannot even be attributed to white, as nothing is which is not substance), it follows that white is not-being—and that not in the sense of a particular not-being, but in the sense that it is not at all. Hence substance is not; for it is true to say that it is white, which we found to mean not-being. If to avoid this we say that even ‘white’ means substance, it follows that ‘being’ has more than one meaning.

In particular, then, being will not have magnitude, if it is substance. For each of the two parts must be in a different sense.

Substance is plainly divisible into other substances, if we consider the mere nature of a definition. For instance, if man is a substance, animal and biped must also be substances. For if not substances, they must be attributes—and if attributes, attributes either of man or of some other subject. But neither is possible.

An attribute is either that which may or may not belong to the subject or that in whose definition the subject of which it is an attribute is involved. Thus sitting is an example of a separable attribute, while snubness contains the definition of nose, to which we attribute snubness. Further, the definition of the whole is not contained in the definitions of the contents or elements of the definitory formula; that of man for instance in biped, or that of white man in white. If then this is so, and if biped is supposed to be an attribute of man, it must be either separable, so that man might possibly not be biped, or the definition of man must come into the definition of biped—which is impossible, as the converse is the case.

If, on the other hand, we suppose that biped and animal are attributes not of man but of something else, and are not each of them a substance, then man too will be an attribute of something else. But we must assume that substance is not the attribute of anything, that the subject of which both biped and animal and each separately are predicated is the subject also of the complex biped animal. Are we then to say that the all is composed of indivisible substances?

Some thinkers did, in point of fact, give way to both arguments. To the argument that all things are one if being means one thing, they conceded that not-being is; to that from bisection, they yielded by positing atomic magnitudes. But obviously it is not true that if being means one thing, and cannot at the same time mean the contradictory of this, there will be nothing which is not, for even if what is not cannot be without qualification, there is no reason why it should not be a particular not-being. To say that all things will be one, if there is nothing besides being itself, is absurd. For who understands ‘being itself’ to be anything but a particular substance? But if this is so, there is nothing to prevent there being many beings, as has been said.

It is, then, clearly impossible for being to be one in this sense.

Book I Chapter 2

Book I Chapter 4