Aristotle: Four Causes

We must inquire into the nature of causes (aitia ), and see what the various kinds of cause are and how many there are. Since our treatment of the subject aims at knowledge, and since we believe that we know a thing only when we can say why it is as it is—which in fact means grasping its primary causes—plainly we must try to achieve this with regard to the way things come into existence and pass way out of it, and all other natural change, so that we may know what their principles are and may refer to these principles in order to explain everything into which we inquire.

1 In one sense, what is described as a cause is that material out of which a thing comes into being and which remains present in it. Such, for instance, is bronze in the case of a statue, or silver in the case of a cup, as well as the genera to which these materials belong.

2 In another sense, the form and pattern are a cause, that is to say the statement of the essence

3 Then there is the initiating source of change or rest: the person who advises an action, for instance, is a cause of the action; the father is the cause of his child; and in general, what produces is the cause of what is changed.

4 Then there is what is a cause insofar as it is an end (telos): this is the purpose of a thing; in this sense, health, for instance, is the cause of a man's going for a walk. "Why," someone asks, "is he going for a walk?" "For the good of his health," we reply, and when we say this we think that we have given the cause of his doing so. All the intermediate things, too, that come into being through the agency of something else for this same end have this as their cause: slimming, purging, drugs, and surgical instruments—all have the same purpose, health, as their cause, although they differ from each other in that some of them are activities, others are instruments. These are pretty well all the senses in which we talk of causes; the consequence of our using the term in all these senses is that there are many causes of the same thing. Both the art of sculpture and the bronze, for instance, are causes of the statue, without either of them being its cause in respect to its being anything other than a statue; they are, however, causes in different ways, the one being its matter, the other the source of the movement that produced it. There are some things that are even each other's causes; working hard, for instance, is a cause of one's fitness, and one's fitness is a cause of one's working hard; but they are not causes in the same way; the one is an end, the other is a source of movement. Again, the same thing will be the case of two contraries, for we will sometimes describe what is by its presence the cause of one thing, as being by its absence the cause of that thing's contrary: for instance, we describe the absence of the pilot as the cause of the ship's being sunk, whereas his presence would have been the cause of its preservation.

But all the causes that we have just mentioned fall into the four most obvious groups. The letters of a syllable, the raw material of a manufactured article, fire and such things in bodies, the parts of a whole, and the premises of a syllogism—all these are causes in the sense of being what a thing comes from; but whereas some are causes in the sense of being a substratum (the parts of a whole are, for instance), others are causes by virtue of being a thing's essence: the whole, the combination, and the form. The seed, the doctor, the adviser, and the producer, in general, are all sources of change or rest.

Other things are causes by virtue of being the end and the good of everything else. For being the purpose means being the best of things and the end of everything else—and let us understand that it makes no difference whether we speak of the real or of the apparent good.

Translated from the Greek by Richard Hooker (1993)