Chapter VI. On this common feature of substance, that it is not in a subject

because concerning species and genera all the remaining accidental predicates are predicated in the mode that was determined above: for you will say that some man is grammatical; therefore you say that both man and animal are grammatical, as was proved a little before; similarly also it is so in other accidental predicates. Therefore species and genera have the second place in underlying; for this reason they are called second substances, and all are called substances, and none are third or fourth.

CHAPTER VI. On this common feature of substance, that it is not in a subject.

These things having been determined concerning principal and second substances, now at this point it remains to determine the properties or passions consequent upon the genus of substance. Therefore first we shall touch on whatever properties belong to substance insofar as it is among the predicables, because those are more proper to this intention of ours. But because a property is what belongs to every instance and always, therefore the things which are properly said to belong to the whole genus and to the whole coordination of substance are common to species and genera.

Therefore let us say that it is common to every substance not to be in a subject in that mode in which an accident is in a subject. For before we distinguished that subject is said according to the name, the same as what is cast beneath or a supposit, and in this way a common nature is in its inferior as in a subject, as genus is in species, and species in an individual, and universally second substance in an inferior and particular. But subject is said of a being complete in itself, which is the cause for an accident, or for another thing, of existing in it; and in this mode nothing except an accident is in a subject, and thus it is common to every substance, both second and first, not to be in a subject.

But this is clear by induction. Principal substance, which is a particular of substance, is neither said of a subject, because nothing underlies it as a supposit, nor is it in a subject as the being of an accident is to be in a subject, because it is existing through itself. But concerning second substances it is similarly manifest that none is in a subject, with subject so called, which is a complete being that gives being to another in itself, which does not have being unless it is in it: for man, which is a second substance, is indeed said of a subject, insofar as the supposit is called the subject when it is predicated of some man, as when it is said, some man is man. But it is not in some man as in a subject, insofar as subject means a complete being giving being to another through this, that it is in it and would not have being unless it were in it. The proof of this is that, just as man, which is a second substance, is not in some man in such a way that it receives being from some man, which it would not have unless it were in him, for man, insofar as it is a second substance and species, is the being of individuals and the being of some man, giving being to particulars, and therefore it is impossible that it receive being on account of the fact that it is in them. Likewise also animal, which is a second substance as genus, is indeed said of a subject, of some man or some animal, but it is not in some animal or man as an accident in a subject.

And according to this it is clear that if such an argumentation is made, namely, second substance is in first substance, and first substance is the subject of second substance; therefore it is in it as in a subject, it sins according to the fallacy of equivocation, because substance in the first premise stands for the supposit, but in the conclusion it stands for a subject complete in itself, which is the subject of an accident.

Further, as was held before, concerning those things which are in a subject as an accident is in a subject, the name indeed sometimes does not prevent being predicated of the subject in which they are, but for their definition to be predicated of the subject, so that it is predicated as the definition of the subject, is impossible, as was shown before. But of second substances, there is predicated of the subject which is the supposit both the name and the definitive account; this is clear, because the name of man, which is

second substance is predicated of some man, for some man is man; and the account similarly, because some man is a rational and mortal animal. Therefore second substance is not of the number of those things which are in a subject as an accident is in a subject.

But this, not to be in a subject, is indeed a property which belongs to every substance and always, but it does not belong to it alone: for it also belongs to difference, which is not in the predicament of substance according to the straight line of the predicables in standing-over and underlying. For difference is not in a subject: for biped and capable of walking, which are divisive differences of mobile animal and constitutive differences of the species man, are said and predicated of the subject in which they are, which is subject as a supposit, namely of man; but they are in no subject insofar as a subject complete in itself gives being to an accident which is in potency. For difference gives to the species being in act in the species: because, as was determined in the science of the Universals, difference is that which leads to being and which is part of the being of the thing that is. Therefore neither biped nor capable of walking is in man in such a way that through being-in it receives that it is; for difference confers being on the species, and does not receive being from it. For if it received being from the species subjected to it, the species would have to be received in the definition of difference as subject is received in the definition of an accident; but this does not happen; rather difference is received in the definition of the species. Therefore it is clear that it is not in the species as an accident. Moreover, of whatever thing difference is predicated as of a subject by name, of the same thing the account or definition of the difference is predicated, as is clear by example: because if capable of walking is said or predicated of man, then also the definitive account of capable of walking is predicated of man, which is to be movable by feet through will or appetite according to progressive motion; for man is capable of walking, man is movable by will with progressive motion.

But here a doubt can arise, whether difference is substance. For it seems that it is not substance on account of what is said: this, not to be in a subject, belongs not to substance alone but also to difference; for through this it seems that difference is not substance.

But this has already been sufficiently determined in the science of the Universals. For that difference which is more properly difference is, according to that which it is and according to its own nature, substance, which is substantial form, which gives being in act to the whole substance, and in this mode gives the being of the whole; but that which is a notion designating the whole being in act is difference, and therefore it is predicated of the whole. Yet if difference is considered insofar as it is related to genus, whose quality consists in its potency, in this way it is related to genus as the perfected being consequent upon the genus, and therefore in this comparison it is compared to genus as the quality of an inseparable accident. Yet this quality is not a quality according to the nature of quality, but is an essential quality, because the potency of the genus is the potency of an imperfect thing, whose imperfection is perfected to act once the potency of the genus has been determined through the difference joined to it; and in this mode substantial form has the mode of quality. But compared to the species which it constitutes in its own being, it is also an essential quality and substance, because nothing constitutes in being except substance; and because thus it has the mode of quality and the effect of substance, therefore it is not substance according to its whole account. And because it is simple and not composed, therefore it cannot fall in the direct line of the coordination of the predicables of substance according to the order of standing-over and underlying, because it does not look to the genus of substance as to the principle of its being; therefore it cannot through itself be a genus. For the first genera are the first principles of things. But looking to another as to its own principle in which it is, it cannot be a first principle, and thus it cannot be a genus. Therefore, since it looks to genus

not as something supposed under a genus, but as to that in which it is as in a natural potency, it follows necessarily that it is in a lateral line, and therefore it is neither in the genus nor wholly extraneous and separated from the genus. And we have handed down the doctrine of this in the science of the Universals in the treatise On Difference; but we speak here only so far as is necessary for the present intention. Therefore because it is not in the genus of substance, on account of this it is said that not to be in a subject belongs not only to substance but also to difference.

But there is something that could disturb one according to this doctrine: so that someone could be moved concerning the parts of principal substances, such as hand, foot, and things of this sort, or even concerning matter and form, from which composite substance comes to be. For those parts in composite substance seem to be as in a subject; for they do not have the being of parts except in the composite, for a hand cut off is not a hand. And thus perhaps someone would think that, according to this doctrine, we are compelled in many ways to say that they are not substances, and conversely, through this reason, that they are not as substances. For those things which are in something as essential or integral parts, through the fact that they are thus in the whole, do not have being in a subject: for there is one mode for something to be in something as a part in a whole, and another mode for being in something as an accident in a subject, as is determined in the fourth book of the Physics.

Nevertheless one must know that a part is not in act except when it is in the whole; but it is a part in potency and not according to act when it is not in the whole, and thus it receives act and account from the whole. But its act and form is its operation which it has according to form, as seeing belongs to the eye, drawing nourishment to the root, defending the fruit from burning heat to the leaf, and carrying out the work commanded by intellect to the hand, and things of this sort. And besides, parts have powers in the whole, and do not have them when they are not in the whole; and therefore cut-off parts receive equivocally those names which they have in the whole. But that in the whole they receive the name and account in some way is from the whole; however an accident does not do this when it is in the whole as in a subject. And therefore there is equivocation when a part is said to be in a whole, and when an accident is said to be in a whole; for an accident is not the form of the part but of the whole, because the subject of an accident is a being complete in itself; but the complete is the whole composite. There is, moreover, also this dissimilarity: because parts in the whole, whether they are essential or integral, constitute the whole according to being, and therefore they are substances of the whole; for an accident is not in the whole as constituting it according to substance, but is as something constitutive in being in whatever way through substance, and therefore in the definition of an accident the subject is received as the cause of the accident; but in the definition of a composite the parts are received as principles of knowing the whole, because the principles of knowing and of being are the same, as is said at the beginning of the Physics ¹. But Aristotle says that we know the composite and whole when we know from what things, and how many, and from what qualities it is.

But from these things certain erring persons object, as Gregory of Nyssa says: Whatever things are in something as endelechy are either in something as an accident, or as a material form which has being outside itself. But the soul as endelechy has being in a body; therefore either it is in it as an accident in a subject, or as a material form; and whichever of these is granted, it follows that it does not have being except in the body, and does not have being outside it. But to this certain persons try to respond, saying that the soul has being in the body as the mover in the moved, as a king in a kingdom and a sailor in a ship, and therefore it is separable from the body and, when separated, has being in itself.

But, with peace granted to those men, those men do not