by Aristotle
7 · Since contraries admit of an intermediate and in some cases have it, the intermediate must be composed of the contraries. For all intermediates are in the [20] same genus as the things between which they stand. For we call those things intermediates, into which that which changes must change first; e.g. if we were to pass from the highest string to the lowest by the shortest way, we should come sooner to the intermediate notes, and in colours if we are to pass from white to black, [25] we shall come sooner to crimson and gray than to black; and similarly in all other cases. But to pass from one genus to another genus (e.g. from colour to figure) is not possible except in an incidental way. Intermediates, then, must be in the same genus as one another and as the things they stand between.
[30] But all intermediates stand between opposites of some kind; for only between these can change take place in virtue of their own nature. Therefore an intermediate is impossible between things which are not opposite; for then there would be change which was not from one opposite towards the other. Among opposites, contradictories admit of no middle term; for contradiction is this—an opposition, one or other [35] side of which must attach to anything whatever, i.e. which has no intermediate. Of other opposites, some are relative, others privative, others contrary. Of relative terms, those which are not contrary have no intermediate. The reason is that they are not in the same genus. For what intermediate could there be between knowledge [1057b1] and the knowable? But between great and small there is one.
If intermediates are in the same genus, as has been shown, and stand between contraries, they must be composed of these contraries. For either there will be a genus including the contraries or there will be none. And if there is a genus in such a [5] way that it is something prior to the contraries, the differentiae which constitute the contrary species of the genus will be contraries prior to the species; for species are composed of the genus and the differentiae. E.g. if white and black are contraries, and one is a piercing colour and the other a compressing colour, these differentiae—piercing [10] and compressing—are prior; so that these are prior contraries of one another (though indeed the species which differ by contrariety are more truly contrary). And the other species, i.e. the intermediates, must be composed of their genus and their differentiae. E.g. all colours which are between white and black [15] must be said to be composed of the genus (i.e. colour) and certain differentiae. But these differentiae will not be the primary contraries; otherwise every colour would be either white or black. They are different, then, from the primary contraries; and therefore they will be between the primary contraries; the primary differentiae are piercing and compressing. Therefore it is with regard to these contraries which do not fall within a genus that we must first ask of what their intermediates are [20] composed. (For things which are in the same genus must be composed of terms in which the genus is not an element, or else be themselves incomposite.) Now contraries do not involve one another in their composition, and are therefore first principles; but the intermediates are either all incomposite, or none of them. But there is something compounded out of the contraries, which is such that there can be a change from a contrary to it sooner than to the other contrary; for it will have less of the quality in question than the one contrary and more than the other. This [25] also, then, will come between the contraries. All the other intermediates also, therefore, are composite; for that which has more of a quality than one thing and less than another is compounded somehow out of the things than which it is said to have more and less respectively. And since there are no other things prior to the contraries and homogeneous with the intermediates, all intermediates must be [30] compounded out of the contraries. Therefore all the inferior classes, both the contraries and their intermediates, will be compounded out of the primary contraries. Clearly, then, intermediates are all in the same genus and intermediate between contraries and compounded out of the contraries.
8 · That which is other in species is other than something in something, and [35] this must belong to both; e.g. if it is an animal other in species, both are animals. The things, then, which are other in species must be in the same genus. For by genus I mean that one identical thing which is predicated of both and is differentiated in no merely accidental way, whether conceived as matter or otherwise. For not only [1058a1] must the common nature attach to the different things, e.g. not only must both be animals, but this very animal must also be different for each (e.g. in the one case horse, in the other man), and therefore this common nature is specifically different for the two things. One then will be in virtue of its own nature one sort of animal, [5] and the other another, e.g. one a horse and the other a man. This difference then must be an otherness of the genus. For I give the name of ‘difference in the genus’ to an otherness which makes the genus itself other.
This, then, will be a contrariety (as can be shown also by induction). For all things are divided by opposites, and it has been proved that contraries are in the [10] same genus. For contrariety was seen to be complete difference; and every difference in species is a difference from something in something; so that this is the same for both and is their genus. (Hence also all contraries which are different in species and not in genus are in the same line of predication, and other than one another in the highest degree—for the difference is complete—, and cannot be [15] present along with one another.) The difference, then, is a contrariety.
This, then, is the meaning of calling two things other in species—that they are contrary, being in the same genus and being indivisible (and those things are the same in species, which have no contrariety, being indivisible); for in the process of division contrarieties arise even in the intermediate stages before we come to the [20] indivisibles. Evidently, therefore, with reference to that which is called the genus, none of the species which belong to the genus is either the same as it or other than it in species (rightly so, for the matter is indicated by negation, and the genus is the matter of that of which it is called the genus, not in the sense in which we speak of the genus of the Heraclidae, but in that in which we speak of a genus in nature), nor [25] is it so with reference to things which are not in the same genus, but it will differ in genus from them, and in species from things in the same genus. For the difference between things which differ in species must be a contrariety; and this belongs only to things in the same genus.
9 · One might raise the question, why woman does not differ from man in [30] species, female and male being contrary, and their difference being a contrariety; and why a female and a male animal are not different in species, though this difference belongs to animal in virtue of its own nature, and not as whiteness or blackness does; both female and male belong to it qua animal. This question is [35] almost the same as the other, why one contrariety makes things different in species and another does not, e.g. ‘with feet’ and ‘with wings’ do, but whiteness and blackness do not. Perhaps it is because the former are modifications peculiar to the genus, and the latter are less so. And since one element is formula and one is matter, [1058b1] contrarieties which are in the formula make a difference in species, but those which are in the compound material thing do not make one. Therefore whiteness in a man, or blackness, does not make one, nor is there a difference in species between the [5] white man and the black man, not even if each of them be denoted by one word. For man plays the part of matter, and matter does not create a difference; for it does not make individual men species of man, though the flesh and the bones of which this man and that man consist are other. The compound thing is other, but not other in species, because in the formula there is contrariety, and man is the ultimate [10] indivisible kind. Callias is formula together with matter; white man, then, is so also, because Callias is white; man, then, is white only incidentally. Nor do a brazen and a wooden circle differ in species; and if a brazen triangle and a wooden circle differ in species, it is not because of the matter, but because there is a contrariety in the [15] formula. But does the matter not make things other
in species, when it is other in a certain way, or is there a sense in which it does? For why is this horse other than this man in species, although their matter is included with their formulae? Doubtless because there is a contrariety in the formula. For while there is a contrariety also between white man and black horse, and it is a contrariety in species, it does not [20] depend on the whiteness of the one and the blackness of the other, since even if both had been white, yet they would have been other in species. And male and female are indeed modifications peculiar to animal, not however in virtue of its substance but in the matter, i.e. the body. This is why the same seed becomes female or male by being acted on in a certain way. We have stated, then, what it is to be other in [25] species, and why some things differ in species and others do not.
10 · Since contraries are other in form, and the perishable and the imperishable are contraries (for privation is a determinate incapacity), the perishable and the imperishable must be different in kind.
Now so far we have spoken of the general terms themselves, so that it might be thought not to be necessary that every imperishable thing should be different from [30] every perishable thing in form, just as not every white thing is different in form from every black thing. For the same thing can be both, even at the same time if it is a universal (e.g. man can be both white and black), and if it is an individual it can still be both; for the same man can be, though not at the same time, white and black. Yet white is contrary to black. [35]
But while some contraries belong to certain things by accident (e.g. those now mentioned and many others), others cannot, and among these are both ‘perishable’ [1059a1] and ‘imperishable’. For nothing is by accident perishable. What is accidental is capable of not being present, but perishableness is one of the attributes that belong of necessity to the things to which they belong; or else one and the same thing may be perishable and imperishable, if perishableness is capable of not belonging to it. [5] Perishableness then must either be the substance or be present in the substance of each perishable thing. The same account holds good for imperishableness also; for both are attributes which are present of necessity. The characteristics, then, in respect of which and in direct consequence of which one thing is perishable and another imperishable, are opposite, so that the things must be different in kind. [10]
Evidently, then, there cannot be Forms such as some maintain, for then one man would be perishable and another imperishable. Yet the Forms are said to be the same in form with the individuals and not homonymous; but things which differ in kind are further apart than those which differ in form.
BOOK XI (K)
1 · That Wisdom is a science of first principles, is evident from the introductory chapters in which we have raised objections to the statements of others about the first principles; but one might ask the question whether Wisdom is to be [20] conceived as one science or as several. If as one, it may be objected that one science always deals with contraries, but the first principles are not contrary. If it is not one, what are these sciences with which it is to be identified?
Further, is it the business of one science or of more to examine the first principles of demonstration? If of one, why of this rather than of any other? If of [25] more, which must these be said to be?
Further, does it investigate all substances or not? If not all, it is hard to say which; but if, being one, it investigates them all, it is doubtful how the same science can embrace several subject-matters.
Further, does it deal with substances only or also with their accidents? If in the [30] case of attributes demonstration is possible, in that of substances it is not. But if the two sciences are different, what is each of them and which is Wisdom? If we think of it as demonstrative, the science of the accidents is Wisdom, but if as dealing with first principles, the science of substances claims the title.
[35] But again the science we are looking for must not be supposed to deal with the causes which have been mentioned in the Physics. For it does not deal with the final cause (for this is the good, and this is found in the field of action and movement; and it is the first mover—for that is the nature of the end—but in the case of things unmovable there is no first mover), and in general it is hard to say whether the [1059b1] science we are now looking for deals with perceptible substances or not with them, but with certain others. If with others, it must deal either with the Forms or with the objects of mathematics. Now evidently the Forms do not exist. (But it is hard to say, even if one suppose them to exist, why the same is not true of the other things of [5] which there are Forms, as of the objects of mathematics. I mean that they place the objects of mathematics between the Forms and perceptible things, as a third class of things besides the Forms and the things in this world; but there is not a third man or horse besides the ideal and the individuals. If on the other hand it is not as they say, [10] with what sort of things must the mathematician be supposed to deal? Certainly not with the things in this world; for none of these is the sort of thing which the mathematical sciences inquire into.) Nor does the science which we are now seeking treat of the objects of mathematics; for none of them can exist separately. But again it does not deal with perceptible substances; for they are perishable.
[15] In general we might raise the question, to which science it belongs to discuss the difficulties about the matter of the objects of mathematics. Neither to natural science (because the whole inquiry of the natural scientist is about the things that have in themselves a principle of movement and rest), nor yet to the science which inquires into demonstration and science; for this is just the subject which it [20] investigates. It remains then that it is the philosophy which we have set before ourselves that treats of those subjects.
One might discuss the question whether the science we are seeking should be said to deal with the principles which are by some called elements. All men suppose [25] these to be present in compound things; but it might be thought that the science we seek should treat rather of universals; for every formula and every science is of universals and not of particulars, so that as far as this goes it would deal with the highest classes. These would be being and unity; for these might most of all be supposed to contain all things that are, and to be most like principles because they [30] are first by nature; for if they perish all other things are destroyed with them; for all things are and are one. But inasmuch as, if one is to suppose them to be genera, they must be genera predicable of their differentiae, and no genus is predicable of any of its differentiae, in this way it would seem that we should not make them genera nor [35] principles. Further, if the simpler is more of a principle than the less simple, and the ultimate members of the genus are simpler than the genus (for they are indivisible, but the genera are divided into many and differing species), the species might seem to be the principles, rather than the genera. But inasmuch as the species are involved in the destruction of the genera, the genera are more like principles; for [1060a1] that which involves another in its destruction is a principle of it. These and others of the kind are the subjects that involve difficulties.
2 · Further, must we suppose something apart from individual things, or is it these that the science we are seeking treats of? But these are infinite in number. But the things that are apart from the individuals are genera or species; and the science [5] we now seek treats of neither of these. The reason why this is impossible has been stated. It is in general hard to say whether one must assume that there is a separable substance besides the sensible substances (i.e. the substances in this world), or that these are the real things and philosophy is concerned with them. For we seem to [10] seek another kind of substance, and this is our problem, i.e. to see if there is something which can exist apart by itself and belongs to no sensible thing.—Further, if there is another substance apart from sensible substances, which kinds of sensible substance must be supposed to have this corresponding to them? Why should one suppose men or horses to have it, and not the other animals or even all [15] lifeless thin
gs? On the other hand to set up other and eternal substances equal in number to the sensible and perishable substances would seem to fall beyond the bounds of probability.—But if the principle we now seek is not separable from corporeal things, what has a better claim to the name than matter? This, however, [20] does not exist in actuality, but exists in potency, and it would seem rather that the form or shape is a more important principle than this; but the form is perishable, so that there is no eternal substance at all which can exist apart and independent. But this is paradoxical; for such a principle and substance seems to exist and is sought by nearly all the best thinkers as something that exists; for how is there to be order [25] unless there is something eternal and independent and permanent?
Further, if there is a substance or principle of such a nature as that which we are now seeking, and if this is one for all things, and the same for eternal and for perishable things, it is hard to say why, if there is the same principle, some of the things that fall under the principle are eternal, and others are not eternal; this is [30] paradoxical. But if there is one principle of perishable and another of eternal things, we shall be in a like difficulty if the principle of perishable things as well is eternal; for why, if the principle is eternal, are not the things that fall under the principle also eternal? But if it is perishable it must have another principle, and that must [35] have yet another, and this will go on to infinity.