by Aristotle
If we consider we find that the syllable is not produced by the letters and [5] juxtaposition, nor is the house bricks and juxtaposition. And this is right; for the juxtaposition or mixing is not produced by those things of which it is the juxtaposition or mixing. And the same is true in the other cases, e.g. if the threshold is characterized by its position, the position is not produced by the threshold, but rather the latter is produced by the former. Nor is man animal and biped, but there [10] must be something besides these, if these are matter,—something which is neither an element in the whole nor produced by an element, but is the substance, which people eliminate and state the matter. If then this is the cause of the thing’s being, and if the cause of its being is its substance, they cannot be stating the substance itself.
This, then, must either be eternal or it must be destructible without being ever [15] in course of being destroyed, and must have come to be without ever being in course of coming to be. But it has been proved and explained elsewhere that no one makes or generates the form, but it is a ‘this’ that is made, i.e. the complex of form and matter that is generated. Whether the substances of destructible things can exist apart, is not yet at all clear; except that obviously this is impossible in some cases—in the case of things which cannot exist apart from the individual instances, [20] e.g. house or utensil. Perhaps neither these things themselves, nor any of the other things which are not formed by nature, are substances at all; for one might say that the nature in natural objects is the only substance to be found in destructible things.
Therefore the difficulty which was raised by the school of Antisthenes and [25] other such uneducated people has a certain appropriateness. They stated that the ‘what’ cannot be defined (for the definition so called is a long formula); but of what sort a thing, e.g. silver, is, they thought it possible to explain, not saying what it is but that it is like tin. Therefore one kind of substance can be defined and formulated, i.e. the composite kind, whether it be the object of sense or of reason; [30] but the primary parts of which this consists cannot be defined, since a definitory formula predicates something of something, and one part of the definition must play the part of matter and the other that of form.
It is also obvious that, if all substances are in a sense numbers, they are so in this sense and not, as some say as numbers of units. For definition is a sort of [35] number; for it is divisible, and into indivisible parts (for definitory formulae are not infinite), and number also is of this nature. And as, when one of the parts of which a number consists has been taken from or added to the number, it is no longer the same number, but a different one, even if it is the very smallest part that has been [1044a1] taken away or added, so the definition and the essence will no longer remain when anything has been taken away or added. And the number must have something in virtue of which it is one thing, while our opponents cannot say if it is one (for either [5] it is not one but a sort of heap, or if it is, we ought to say what it is that makes one out of many); and the definition is one, but similarly they cannot say what makes it one. And this is natural; for the same reason is applicable, and substance is one in the sense which we have explained, and not, as some say, by being a sort of unit or point; each is a complete reality and a definite nature. And as number does not admit of [10] the more and the less, neither does substance, in the sense of form, but if any substance does, it is only the substance which involves matter. Let this then suffice for an account of the generation and destruction of so-called substances—in what sense it is possible and in what sense impossible—and of the reduction of things to number.
[15] 4 · Regarding material substance we must not forget that even if all things have the same primary constituent or constituents, and if the same matter serves as starting-point for their generation, yet there is a matter proper to each, e.g. the sweet or the fat of phlegm, and the bitter, or something else, of bile; though perhaps [20] these have the same constituent. And there come to be several matters for the same thing, when the one matter is matter for the other, e.g. phlegm comes from the fat and from the sweet, if the fat comes from the sweet; and it comes from bile by analysis of the bile into its ultimate matter. For one thing comes from another in two senses, either because it will be found at a later stage of development, or because it is produced if the other is analysed into its original constituents. When [25] the matter is one, different things may be produced owing to difference in the moving cause, e.g. from wood may be made both a chest and a bed. But some different things must have their matter different, e.g. a saw could not be made of wood, nor is this in the power of the moving cause; for it could not make a saw of [30] wool or of wood. But if, as a matter of fact, the same thing can be made of different material, clearly the art, i.e. the moving principle, is the same; for if both the matter and the moving principle were different, the product would be too.
When one inquires what is the cause, one should, as causes are spoken of in several senses, state all the possible causes. E.g. what is the material cause of man? The menstrual fluid. What is the moving cause? The semen. The formal cause? His essence. The final cause? His end. But perhaps the latter two are the same.—We [1044b1] must state the proximate causes. What is the material cause? Not fire or earth, but the matter peculiar to the thing.
Regarding generable natural substances, if the causes are really these and of this number and we have to learn the causes, we must inquire thus, if we are to [5] inquire rightly. But in the case of natural but eternal substances another account must be given. For perhaps some have no matter, or not matter of this sort but only such as can be moved in respect of place. Nor does matter belong to those things which exist by nature but are not substances; their substratum is the substance. E.g. what is the cause of an eclipse? What is its matter? There is none; the moon is that [10] which suffers eclipse. What is the moving cause which extinguishes the light? The earth. The final cause perhaps does not exist. The formal principle is the definitory formula, but this is obscure if it does not include the cause. E.g. what is eclipse? Deprivation of light. But if we add ‘by interposition of the earth’, this is the formula which includes the cause. In the case of sleep it is not clear what it is that [15] proximately has this affection. Surely the animal, it will be said. Yes, but the animal in virtue of what, i.e. what is the proximate subject? The heart or some other part. Next, by what is it produced? Next, what is the affection—that of the proximate subject, not of the whole animal? Shall we say that it is immobility of such and such a kind? Yes, but to what process in the proximate subject is this due? [20]
5 · Since some things are and are not, without coming to be and ceasing to be, e.g. points, if they can be said to be, and in general forms (for it is not white that comes to be, but the wood comes to be white, if everything that comes to be comes from something and comes to be something), not all contraries can come from one another, but it is in different senses that a white man comes from a black man, and [25] white comes from black. Nor has everything matter, but only those things which come to be and change into one another. Those things which, without ever being in course of changing, are or are not, have no matter.
There is difficulty in the question how the matter of each thing is related to its contrary states. E.g. if the body is potentially healthy, and disease is contrary to [30] health, is it potentially both? And is water potentially wine and vinegar? We answer that it is the matter of one in virtue of its positive state and its form, and of the other in virtue of the privation of its positive state and the corruption of it contrary to its nature. It is also hard to say why wine is not said to be the matter of vinegar nor potentially vinegar (though vinegar is produced from it), and why the living man is [35] not said to be potentially dead. In fact they are not, but the corruptions in question are accidental, and it is the matter of the animal that is itself in virtue of its [1045a1] corruption the potency and matter of a corpse, and it is water that is the matter of vinegar. For the one comes from the other as night from d
ay. And all things which change thus into one another must be reduced to their matter, e.g. if from a corpse is [5] produced an animal, the corpse is first reduced to its matter, and only then becomes an animal; and vinegar is first reduced to water, and only then becomes wine.
6 · To return to the difficulty which has been stated with respect to definitions and numbers, what is the cause of the unity of each of them? In the case of all things which have several parts and in which the whole is not, as it were, a [10] mere heap, but the totality is something besides the parts, there is a cause of unity; for as regards material things contact is the cause in some cases, and in others viscidity or some other such quality. And a definition is a formula which is one not by being connected together, like the Iliad, but by dealing with one object.—What [15] then is it that makes man one; why is he one and not many, e.g. animal—biped, especially if there are, as some say, an ideal animal and an ideal biped? Why are not those Ideas the ideal man, so that men would exist by participation not in man, nor in one Idea, but in two, animal and biped? And in general man would be not one but [20] more than one thing, animal and biped.
Clearly, then, if people proceed thus in their usual manner of definition and speech, they cannot explain and solve the difficulty. But if, as we say, one element is matter and another is form, and one is potentially and the other actually, the [25] question will no longer be thought a difficulty. For this difficulty is the same as would arise if ‘round bronze’ were the definition of cloak; for this name would be a sign of the definitory formula, so that the question is, what is the cause of the unity of round and bronze? The difficulty disappears, because the one is matter, the other [30] form. What then is the cause of this—the reason why that which was potentially is actually,—what except, in the case of things which are generated, the agent? For there is no other reason why the potential sphere becomes actually a sphere, but this was the essence of either. Of matter some is the object of reason, some of sense, and [35] part of the formula is always matter and part is actuality, e.g. the circle is a figure which is plane. But of the things which have no matter, either for reason or for [1045b1] sense, each is by its nature essentially a kind of unity, as it is essentially a kind of being—a ‘this’, a quality, or a quantity. And so neither ‘existent’ nor ‘one’ is present in definitions, and an essence is by its very nature a kind of unity as it is a kind of being. This is why none of these has any reason outside itself for being one, nor for [5] being a kind of being; for each is by its nature a kind of being and a kind of unity, not as being in the genus ‘being’ or ‘one’ nor in the sense that being and unity can exist apart from particulars.
Owing to the difficulty about unity some speak of participation, and raise the question, what is the cause of participation and what is it to participate; and others [10] speak of communion, as Lycophron says knowledge is a communion of knowing with the soul; and others say life is a composition or connexion of soul with body. Yet the same account applies to all cases; for being healthy will be either a communion or a connexion or a composition of soul and health, and the fact that the [15] bronze is a triangle will be a composition of bronze and triangle, and the fact that a thing is white will be a composition of surface and whiteness.—The reason is that people look for a unifying formula, and a difference, between potentiality and actuality. But, as has been said, the proximate matter and the form are one and the same thing, the one potentially, the other actually. Therefore to ask the cause of their being one is like asking the cause of unity in general; for each thing is a unity, [20] and the potential and the actual are somehow one. Therefore there is no other cause here unless there is something which caused the movement from potentiality into actuality. And all things which have no matter are without qualification essentially unities.
BOOK IX (Θ)
1 · We have treated of that which is primarily and to which all the other categories of being are referred—i.e. of substance. For it is in virtue of the formula of substance that the others are said to be—quantity and quality and the like; for all [30] will be found to contain the formula of substance, as we said in the first part of our work. And since ‘being’ is in one way divided into ‘what’, quality, and quantity, and is in another way distinguished in respect of potentiality and fulfillment, and of function, let us discuss potentiality and fulfillment. First let us explain potentiality [35] in the strictest sense, which is, however, not the most useful for our present purpose. For potentiality and actuality extend further than the mere sphere of motion. But [1046a1] when we have spoken of this first kind, we shall in our discussions of actuality explain the other kinds of potentiality.
We have pointed out elsewhere that ‘potentiality’ and the word ‘can’ have [5] several senses.1 Of these we may neglect all the potentialities that are so called homonomously. For some are called so by analogy, as in geometry; and we say things can be or cannot be because in some definite way they are or are not.
But all potentialities that conform to the same type are starting points, and are called potentialities in reference to one primary kind, which is a starting-point of [10] change in another thing or in the thing itself qua other. For one kind is a potentiality for being acted on, i.e. the principle in the very thing acted on, which makes it capable of being changed and acted on by another thing or by itself regarded as other; and another kind is a state of insusceptibility to change for the worse and to destruction by another thing or by the thing itself qua other, i.e. by a principle of change. In all these definitions is contained the formula of potentiality in the [15] primary sense.—And again these so-called potentialities are potentialities either of acting merely or of being acted on, or of acting or being acted on well, so that even in the formulae of the latter the formulae of the prior kinds of potentiality are somehow contained.
Obviously, then, in a sense the potentiality of acting and of being acted on is one (for a thing may be capable either because it can be acted on or because [20] something else can be acted on by it), but in a sense the potentialities are different. For the one is in the thing acted on; it is because it contains a certain motive principle, and because even the matter is a motive principle, that the thing acted on is acted on, one thing by one, another by another; for that which is oily is [25] inflammable, and that which yields in a particular way can be crushed; and similarly in all other cases. But the other potentiality is in the agent, e.g. heat and the art of building are present, one in that which can produce heat and the other in the man who can build. And so in so far as a thing is an organic unity, it cannot be acted on by itself; for it is one and not two different things. And want of potentiality, [30] or powerlessness, is the privation which is contrary to potentiality of this sort, so that every potentiality belongs to the same subject and refers to the same process as a corresponding want of potentiality. Privation has several senses; for it means that which has not a certain quality and that which might naturally have it but has not got it, either in general of when it might naturally have it, and either in some particular way, e.g. when it completely fails to have it, or when it in any degree fails to have it. And in certain cases if things which naturally have a quality lose it by [35] violence, we say they suffer privation.
2 · Since some such principles are present in soulless things, and others in [1046b1] things possessed of soul, and in soul and in the rational part of the soul, clearly some potentialities will be non-rational and some will be accompanied by reason. This is why all arts, i.e. all productive forms of knowledge, are potentialities; they are principles of change in another thing or in the artist himself considered as other.
[5] And each of those which are accompanied by reason is alike capable of contrary effects, but one non-rational power produces one effect; e.g. the hot is capable only of heating, but the medical art can produce both disease and health. The reason is that science is a rational formula, and the same rational formula explains a thing and its privation, only not in the same way; and in a sense it
applies [10] to both, but in a sense it applies rather to the positive fact. Therefore such sciences must deal with contraries, but with one in virtue of their own nature and with the other not in virtue of their nature; for the rational formula applies to one object in virtue of that object’s nature, and to the other, in a sense, accidentally. For it is by denial and removal that it explains the contrary; for the contrary is the primary [15] privation, and this is the entire removal of the positive term. Now since on the one hand contraries do not occur in the same thing, but on the other hand science is a potentiality which depends on the possession of a rational formula, and the soul possesses a principle of movement; therefore, on the other hand, the healthy produces only health and what can heat only heat and what can cool only cold, but the scientific man, on the other hand, produces both the contrary effects. For there [20] is a rational formula which applies to both, though not in the same way, and it is in a soul which possesses a principle of movement; so that the soul will start both processes from the same principle, applying them to the same object. And so the things whose potentiality is according to a rational formula act contrariwise to the things whose potentiality is non-rational; for the products of the former are included under one principle, the rational formula.
It is obvious also that the potentiality of merely doing a thing or having it done [25] to one is implied in that of doing it or having it done well, but the latter is not always implied in the former: for he who does a thing well must do it, but he who does it merely need not do it well.