Aristotle
Metaphysics

from The Metaphysics

Book A

All men by nature desire understanding. A sign of this is their liking of sensations; for even apart from the need for these and other things they are liked for their own sake and of all sensations those received by means of the eyes are liked the most for not only for the sake of doing something else, but even if we are not going to do something else, we prefer, as the saying goes, seeing to other sensations. The cause of this is the fact that of all the sensations seeing makes us know in the highest degree and makes clear many differences in things.

Now art comes into being when out of many notions from experience we form one universal belief concerning similar facts. For to have a belief that when Callias was having this disease this benefited him, and similarly with Socrates and many other individuals, is a matter of experience; but to have a belief that this benefited all persons of a certain kind who were having this sickness such as the phlegmatic  or the bilious or those burning with high fever is a matter of art.

Experience does not seem to differ from art where something is to be done; in fact we observe that men of experience succeed more than men who have the theory but have no experience. The cause of this is that experience is knowledge of individuals but art is universal knowledge and all actions and productions deal with individuals. The doctor does not cure a man universally taken, except accidentally, but Callias or Socrates or someone else to whom also the essence of man happens to belong. If then someone without experience has the theory and knows the universal but is ignorant of the individual included under this universal he will often fail to cure; for it is rather the individual that is curable. Nevertheless we regard understanding and comprehension as belonging more to art than to experience and we believe that artists are wiser than men of experience; and this indicates that wisdom attributed to men in virtue of their understanding rather than their experience in-as-much-as men of understanding know the cause but men of experience do not. . . .

Book T

There is a science which investigates being qua being and what belongs essentially to it. This science is not  the same as any of the so-called “special sciences”; for none or those sciences examines universally being qua being, but, cutting off some part of it, each of them investigates the attributes of that part, as in the case of mathematical sciences. Now since we are seeking the principles and the highest causes, clearly these must belong to some nature in virtue or itself. If, then, also those who were seeking the elements of things were seeking these principles, these elements too must be elements of being, not accidentally, but qua being. Accordingly, it is of being qua being that we, too, must find the first causes.

Book Z

The term “being” is used in several senses. . . . In one sense, it signifies a whatness and a this; in another, it signifies a quality or a quantity or one of the others which are predicated in this way. Although “being” is used in so many different senses, it is evident that of these the primary sense is whatness, and used in this sense it signifies a substance. For when we state that this has some quality, we say that it is good or bad but not that it is three cubits long or a man; but when we state what it is, we say that it is a man or a god but not white or hot or three cubits long. The others are called “beings” in view of the fact that they are quantities of being which is spoken or in this primary sense, or qualities of it, or affections of it, or something else of this kind.... Thus, being in the primary sense, not in the qualified sense but without qualification, would be a substance.

The term “substance” is spoken of, if not in more, still in four main senses; for the essence is thought to be the substance of an individual, and the universal, and the genus, and fourthly the underlying subject. The subject is that of which the others are said, but the subject is not said of anything else. And so we must describe first the subject for the primary subject is thought to be a substance in the highest degree.

From what has been said it follows that matter is a substance. But this is impossible; for to be separable and a this is thought to belong most of all to a substance. Accordingly, the form or the composite would seem to be a substance to a higher degree than the matter. The composite substance, that is, the composite of matter and shape, may be laid aside; for it is posterior and clear. Matter, too, is in a sense evident. But we must examine the third, for this is the most perplexing.

In one sense, the subject is said to be the matter; in another sense it is said to be the form; in a third, it is said to he a composite of these. By “matter” I mean, for instance, bronze; by the “form,” the shape of its outward appearance; and by “the composite of these,” the statue as a composite. Thus, if the form is prior to matter and is a being to a higher degree than the matter, for the same reason it will be prior to the composite of form and matter.

. . . here, the purpose is to start with what is more known to the individual and proceed to make known to the individual what is known by nature. Now what is known and first to each individual is often known lightly and has little or no being. Nevertheless, from what is poorly knowable but knowable to oneself one must make an effort to know what is generally knowable, proceeding . . . from what is knowable to oneself.

It is also evident that most of what are regarded as substances are potentialities. These are the parts of animals (for none of them exists separately, and when separated, even then, they all exist as matter), and earth, and fire, and air; for none of these is one, but they all exist like a heap until they are transformed and a unity is produced out of them. One might he led to believe that, most of all, the parts of living things which are near the soul exist both actually and potentially, in view of the fact that they have their principles of motion somewhere in their joints; and on account of this, some animals continue living after they are divided. Yet, when the animal is one and is continuous by nature, and not by force or even by being grown together, every part exists potentially; for that which is one by force or by being grown together is abnormal.

Book H

It is evident . . . that if the substance is the cause of being of each thing, then it is in these differentiae that we must seek the cause of the being of each of these things. Now none of these differentiae is a substance, not even if combined, but in each case it is something analogous to substance; and just as in substances that which is a predicate of matter is the actuality itself, so also in the other definitions, that which is a predicate is to the highest degree the actuality. For example, if we are to define a threshold, we should say “wood or stone in such-and-such a position” (or, also the final cause is present in some cases), and ice as “water frozen or condensed in such-and-such a way;” and we should define harmony as “such-and-such a combination of high and low,” and the rest in the same manner.

It is evident from these that there is a distinct actuality for distinct matter, and a distinct formula .... On account of this, in defining what a house is, those who say it is stones and bricks and wood speak of what is potentially a house, for these are the matter; those who say that it is a receptacle for sheltering animals or goods, or some other such thing, speak of the actuality of the house. But those who combine both, speak of the third kind or substance, the one composed of matter and form . . . .

From what has been said it is evident what a sensible substance is and how it exists; in one sense it is the matter, in another it is the form or actuality, and in a third it is the composite or these two.

Book O

Since we have discussed what is called “a potency” with respect to action, let us explain what actuality is and what sort of object it is. For if this is distinguished, the potential [or capable], too, will be at the same time clear in view of the fact that by “potential” we mean not only that whose nature is to move another or to be moved by another (whether without qualification or in some manner), but also something else; and it is because of our inquiry into the later sense of “potential” that we have discussed the former senses.

. . . things which are posterior in generation are prior in form or in substance: for example, an adult is prior to a child, and a man is prior to seed; for the former in each case already has the form, the later does not. Also, everything which is being generated proceeds towards a principle and an end. For the final cause [or, that for the sake of which] is a principle, and generation is of the sake of an end; and the end is the actuality, and potentiality is viewed as being for the sake of this. Animals do not see in order to have sight, but they have sight in order to see. Likewise, men have the art of building in order to build, and men have the power of investigation in order to investigate. . . .

. . . performance is an end, and actuality is performance. And so even the name “actuality” is derived from the name “work” and points to “actuality.”

It is evident, then, that actuality is prior to potency and to every principle of change.

Book V

Since the account given in this manner is possible, and if it were not, the universe would have been generated from Night, or from the togetherness of all things or from nonbeing, the difficulties may be regarded as solved, and so there is something which is always moved with an unceasing motion, which is circular; and this is clear not only by arguments but also from the facts. So, the first heaven must be eternal; and, further, there is also something which this moves. And since that which is moved and is a mover is thus an intermediate, there is something which causes motion without being moved, and this is eternal, a substance, and an actuality. And this is the way in which the object of desire or the intelligible object moves, namely, without itself being moved. Of these, the primary objects are the same, for the object of desire is that which appears to be noble, and the primary object of wish is that which is noble.

Such, then, is the principle upon which depends the heaven and nature. And its activity is like the best which we can have but for a little while. For it exists in this manner eternally (which is impossible for us), since its actuality is also pleasure. And it is because of this [activity] that being awake, sensing, and thinking are most pleasant, and hopes and memories are pleasant because of these. Now thinking according to itself is of the best according to itself, and thinking in the highest degree is of that which is best in the highest degree. Thus, in partaking of the intelligible, it is of Himself that the Intellect is thinking. . . .