Works 4 part 1/3

I, II, III, IV, V, VI, VII. PROOEMIUM. Since a small error in the beginning is a great one in the end, according to the Philosopher in Book I of On the Heavens and the World, while being and essence are the things first conceived by the intellect, as Avicenna says at the beginning of his Metaphysics—therefore, lest from ignorance of them error should arise, in order to open up the difficulty concerning them, we must say what is signified by the name 'essence' and by 'being,' and how it is found in diverse things, and how it stands in relation to the logical intentions, namely genus, species, and difference. [I].

But since we ought to take the knowledge of simple things from composite ones, and to come from what is posterior into what is prior, so that, beginning from easier things, the teaching may become more fitting—therefore we must proceed from the signification of 'being' to the signification of 'essence.' It must be known, then, that, as the Philosopher says in Book V of the Metaphysics, 'being' in itself is said in two ways: in one way, that which is divided through the ten categories; in another way, that which signifies the truth of propositions. Now the difference between these is that in the second way everything can be called a being of which an affirmative proposition can be formed, even if it posits nothing in reality. In this way privations and negations are called beings;

for we say that affirmation is opposed to negation, and that blindness is in the eye. But in the first way nothing can be called a being except that which posits something in reality. Hence in the first way blindness and the like are not beings. The name 'essence,' therefore, is not taken from 'being' said in the second way, for in this way some things are called beings which have no essence, as is evident in privations; but essence is taken from 'being' said in the first way. Hence the Commentator says in the same place that being, said in the first way, is what signifies the essence of a thing.

And since, as has been said, being said in this way is divided through the ten categories, it is necessary that essence signify something common to all natures through which diverse beings are placed in diverse genera and species, just as humanity is the essence of man, and so of other things. And since that through which a thing is constituted in its proper genus or species is that which is signified by the definition indicating what the thing is, hence it is that the name 'essence' is changed by the philosophers into the name 'quiddity.' And this is what the Philosopher frequently calls 'what it was to be,' that is, that through which something has being as a 'what.'

It is also called 'form,' inasmuch as through form the determinateness of each thing is signified, as Avicenna says in Book II of his Metaphysics. This is also called by another name, 'nature,' taking 'nature' according to the first of those four modes which Boethius assigns in his book On the Two Natures—namely, according as 'nature' is said of everything that can in any way be grasped by the intellect. For a thing is not intelligible except through its definition and essence. And thus too the Philosopher says in Book V of the Metaphysics that every substance is a nature. Yet the name 'nature' taken in this way seems to signify the essence of a thing inasmuch as it has an ordering toward the proper operation of the thing, since no thing is destitute of its proper operation.

The name 'quiddity,' however, is taken from this, that it is signified through the definition. But it is called 'essence' inasmuch as through it and in it a being has its being. [II]. But since 'being' is said absolutely and primarily of substances, and posteriorly and as it were in a qualified sense of accidents, hence it is that essence is properly and truly in substances, but in accidents it is in a certain way and in a qualified sense. Now of substances, some are simple and some composite, and in both there is essence, but in the simple ones in a truer and nobler manner, according as they also have a nobler being. For they are the cause of those things which are composite—at least the first simple substance, which is God.

But since the essences of those substances are more hidden from us, therefore we must begin from the essences of composite substances, so that the teaching may become more fitting by beginning from easier things. In composite substances, then, form and matter are known, as in man the soul and the body. But it cannot be said that either of these alone is called the essence. For that matter alone is not the essence of a thing is plain, because a thing is both knowable through its essence and is ordered in a species or genus. But matter is neither a principle of knowledge, nor is anything determined to a genus or species according to it, but only according to that by which something is in act.

Nor can the form alone be called the essence of a composite substance, although some try to assert this. For from what has been said it is plain that the essence is that which is signified through the definition of a thing. But the definition of natural substances contains not only the form but also the matter; otherwise natural and mathematical definitions would not differ. Nor can it be said that matter is placed in the definition of a natural substance as something added to its essence, or as a being outside its essence, because this mode of definition is proper to accidents, which do not have a perfect essence. Hence it is necessary that in their definition they receive their subject, which is outside their genus.

It is plain, therefore, that essence comprehends matter and form. But it cannot be said that essence signifies the relation which is between matter and form, or something superadded to them, because this would necessarily be an accident and extraneous to the thing, nor would the thing be known through it—all of which belong to essence. For through the form, which is the act of the matter, matter becomes a being in act and a 'this something.' Hence that which supervenes does not give being in act to the matter simply, but being in act of a certain sort, just as accidents also do, as whiteness makes a thing actually white. Hence too, when such a form is acquired, a thing is not said to be generated simply, but in a qualified sense.

It remains, therefore, that the name 'essence' in composite substances signifies that which is composed of matter and form. And to this the word of Boethius in his commentary on the Categories agrees, where he says that 'ousia' signifies the composite. For 'ousia' among the Greeks is the same as 'essence' among us, as he himself says in his book On the Two Natures. Avicenna also says that the quiddity of composite substances is the very composition of form and matter. The Commentator too says, on Book VII of the Metaphysics: the nature which species have in generable things is a certain middle, that is, something composed of matter and form.

To this reason also agrees, because the being of a composite substance is not that of the form alone, nor of the matter alone, but of the composite itself. Now essence is that according to which a thing is said to be. Hence it is necessary that the essence, by which a thing is denominated a being, be not the form alone nor the matter alone, but both—although the form alone is in its own way the cause of this kind of being.

For so we see in other things which are constituted from several principles, that the thing is not denominated from one of those principles alone, but from that which embraces both, as is evident in flavors: because from the action of the heat digesting the moist, sweetness is caused, and although in this way heat is the cause of sweetness, yet a body is not denominated 'sweet' from heat, but from a flavor which embraces the hot and the moist. But since matter is the principle of individuation, from this it perhaps seems to follow that essence, which embraces in itself both matter and form, is only particular and not universal.

From which it would follow that universals would not have a definition, if essence is that which is signified through the definition. And therefore it must be known that matter taken in just any way is not the principle of individuation, but only signate matter. And I call 'signate matter' that which is considered under determinate dimensions. Now this matter is not placed in the definition of man inasmuch as he is man, but it would be placed in the definition of Socrates, if Socrates had a definition. In the definition of man, however, non-signate matter is placed; for in the definition of man this bone and this flesh are not placed, but bone and flesh absolutely, which are the non-signate matter of man. [III].

So therefore it is plain that the essence of man and the essence of Socrates do not differ except according to the signate and the non-signate. Hence the Commentator says, on Book VII of the Metaphysics: Socrates is nothing other than animality and rationality, which are his quiddity. So too the essence of the genus and of the species differ according to the signate and the non-signate, although the mode of designation is different in each case, because the designation of the individual with respect to the species is through matter determined by dimensions, whereas the designation of the species with respect to the genus is through the constitutive difference, which is taken from the form of the thing.

But this determination or designation which is in the species with respect to the genus is not through something existing in the essence of the species which is in no way in the essence of the genus; on the contrary, whatever is in the species is also in the genus as something undetermined. For if 'animal' were not the whole of what man is, but a part of him, it would not be predicated of him, since no integral part is predicated of its whole. But how this comes about can be seen if one examines how 'body' differs according as it is taken as a part of 'animal' and according as it is taken as a genus. For it cannot be a genus in the way in which it is an integral part. This name 'body,' therefore, can be taken in several ways.

For 'body,' inasmuch as it is in the genus of substance, is so called from the fact that it has such a nature that in it three dimensions can be designated; for the three dimensions themselves, when designated, are 'body,' which is in the genus of quantity. Now it happens in things that what has one perfection may also attain to a further perfection, as is evident in man, who has both a sensitive nature and, beyond that, an intellective one. Similarly too, beyond this perfection, which is to have such a form that in it three dimensions can be designated, another perfection can be added, such as life or something of this kind.

This name 'body,' therefore, can signify a certain thing which has such a form that from it there follows in the thing itself the designability of three dimensions with precision—that is, in such a way that from that form no further perfection follows; but if anything else is superadded, it is beyond the signification of 'body' so called. And in this way 'body' will be an integral and material part of 'animal,' because thus the soul will be beyond that which is signified by the name 'body' and will be supervening upon the body itself, so that from these two, namely soul and body, as from parts, the animal will be constituted.

This name 'body' can also be taken in this way, so that it signifies a certain thing which has such a form that from it three dimensions can be designated in it, whatever that form may be, whether from it some further perfection can arise or not. And in this way 'body' will be the genus of 'animal,' because in 'animal' there is nothing to take that is not implicitly contained in 'body.' For the soul is not a form other than that through which in that thing the three dimensions could be designated; and therefore, when it was said that 'body' is that which has such a form from which three dimensions can be designated in it, it was understood: whatever form it might be, whether animality or stoniness or any other whatever.

And thus the form of 'animal' is implicitly contained in the form of 'body,' inasmuch as 'body' is its genus. And such too is the relation of 'animal' to 'man.' For if 'animal' named only a certain thing which has such a perfection that it can sense and be moved through a principle existing in itself, with the exclusion of another perfection, then whatever further perfection might supervene would relate to 'animal' in the manner of a part, and not as something implicitly contained in the notion of 'animal,' and thus 'animal' would not be a genus; but it is a genus inasmuch as it signifies a certain thing from whose form there can arise sensation and motion, whatever that form may be, whether it be a sensible soul only or a sensible and rational one at the same time.

So therefore the genus signifies indeterminately the whole of that which is in the species; for it does not signify the matter alone. Similarly too the difference signifies the whole and does not signify the form alone; and also the definition signifies the whole, and so too the species. But yet in different ways, because the genus signifies the whole as a certain denomination determining that which is material in the thing, without the determination of the proper form. Hence the genus is taken from matter, although it is not matter, as is plain from the fact that 'body' is so called from the fact that it has such a perfection that three dimensions can be designated in it; which perfection is indeed materially disposed toward a further perfection.

The differentia, on the other hand, is conversely like a certain denomination taken determinately from a form, apart from the fact that determinate matter belongs to the first concept of it. This is clear when one says 'animate,' namely that which has a soul; for it is not thereby determined what it is, whether a body or something else. Hence Avicenna says that the genus is not understood in the differentia as a part of its essence, but only as a being outside its essence, just as the subject also belongs to the concept of the properties. And therefore the genus, too, is not predicated of the differentia, properly speaking, as the Philosopher says in Book III of the Metaphysics and in Book IV of the Topics, except perhaps as the subject is predicated of a property.

But the definition or species comprehends both, namely the determinate matter, which the name of the genus designates, and the determinate form, which the name of the differentia designates. From this is clear the reason why genus, species, and differentia stand proportionally to matter, form, and the composite in nature, although they are not the same as these; for the genus is not matter, but is taken from matter as signifying the whole, nor is the differentia form, but is taken from form as signifying the whole. Hence we say that man is a rational animal, and not that he is composed of the animal and the rational, as we say that he is composed of soul and body.

For man is said to be composed of soul and body as a certain third thing constituted from two things, which is neither of them. For man is neither soul nor body. But if man be said in some way to be composed of the animal and the rational, this will not be as a third thing made from two things, but as a third concept made from two concepts. For the concept of 'animal' is without the determination of a special form, expressing the nature of the thing from that which is material with respect to its ultimate perfection. But the concept of this differentia, the 'rational,' consists in the determination of a special form. From these two concepts is constituted the concept of the species or of the definition.

And therefore, just as a thing constituted from certain things does not receive the predication of those things from which it is constituted, so neither does a concept receive the predication of those concepts from which it is constituted. For we do not say that the definition is the genus or the differentia.

Now although the genus signifies the whole essence of the species, it is nevertheless not necessary that of diverse species which share the same genus there be one essence, because the unity of the genus proceeds from its very indetermination or indifference—yet not in such a way that what is signified by the genus is one nature numerically in the diverse species, to which is superadded another thing that is the differentia determining it, as a form determines matter that is one in number. Rather, the genus signifies a certain form, yet not determinately this one or that one, which the differentia expresses determinately—and this latter is no other than that which was signified indeterminately by the genus.

And therefore the Commentator says in Book XI of the Metaphysics that prime matter is called one by the removal of all forms, but the genus is called one by the community of the signified form. Hence it is clear that, by the addition of the differentia, once that indetermination is removed which was the cause of the genus's unity, the species remain diverse in essence.

And because, as has been said, the nature of the species is indeterminate with respect to the individual just as the nature of the genus is with respect to the species, hence it follows that, just as that which is the genus, inasmuch as it was predicated of the species, implied in its signification—although indistinctly—the whole that is determinately in the species, so too that which is the species, inasmuch as it is predicated of the individual, must signify the whole that is essentially in the individual, though indistinctly. And in this manner the essence of the species is signified by the name 'man,' whence 'man' is predicated of Socrates. But if the nature of the species be signified with the precision of designated matter, which is the principle of individuation, then it will stand in the manner of a part.

And in this manner it is signified by the name 'humanity'; for 'humanity' signifies that whereby man is man. But designated matter is not that whereby man is man; and thus it is in no way contained among those things by which man has it that he is man. Since, therefore, 'humanity' includes in its concept only those things by which man has it that he is man, it is clear that from its signification designated matter is excluded or cut off. And because a part is not predicated of the whole, hence it is that 'humanity' is predicated neither of 'man' nor of Socrates.

Hence Avicenna says that the quiddity of a composite is not the composite itself whose quiddity it is, although the quiddity itself is also composite—just as 'humanity,' although it is composite, is not man, but rather must be received in something that is designated matter. But because, as has been said, the designation of the species with respect to the genus is by the form, while the designation of the individual with respect to the species is by the matter, therefore the name signifying that from which the nature of the genus is taken, with the precision of the determinate form perfecting the species, must signify the material part of the whole, as the body is the material part of man.

But the name signifying that from which the nature of the species is taken, with the precision of designated matter, signifies the formal part. And therefore 'humanity' is signified as a certain form, and it is said to be the form of the whole—not indeed as something superadded to the essential parts, namely the form and the matter, in the way that the form of a house is superadded to its integral parts, but rather it is a form which is the whole, that is, embracing both form and matter, yet with the precision of those things by which matter is apt to be designated.

Thus, therefore, it is clear that 'man' and 'humanity' both signify the essence of man, but in different ways, as has been said: for the name 'man' signifies it as a whole, inasmuch, namely, as it does not cut off the designation of matter, but contains it implicitly and indistinctly, just as it was said that the genus contains the differentia; and therefore the name 'man' is predicated of individuals. But the name 'humanity' signifies it as a part, because it does not contain in its signification anything except that which belongs to man inasmuch as he is man, and cuts off every designation. Hence it is not predicated of individual men.

And on this account the name 'essence' too is sometimes found predicated of a thing—for we say that Socrates is a certain essence—and sometimes it is denied, as when we say that the essence of Socrates is not Socrates. [IV] Having therefore seen what is signified by the name 'essence' in composite substances, we must see how it stands in relation to the notion of genus, species, and differentia. But because that to which the notion of genus or species or differentia belongs is predicated of this signate singular, it is impossible that the notion of the universal, namely of genus or species, should belong to the essence according as it is signified in the manner of a part, as by the name 'humanity' or 'animality.'

And therefore Avicenna says that 'rationality' is not the differentia but the principle of the differentia; and by the same reasoning 'humanity' is not the species, nor is 'animality' the genus. Likewise, neither can it be said that the notion of genus or species belongs to the essence according as it is a certain thing existing outside the singulars, as the Platonists held, because in that case genus and species would not be predicated of this individual; for it cannot be said that Socrates is that which is separated from him; nor again would that separated thing avail toward the cognition of this singular.

And therefore it remains that the notion of genus or species belongs to the essence according as it is signified in the manner of a whole, as by the name 'man' or 'animal,' inasmuch as it implicitly and indistinctly contains this whole that is in the individual. Now nature or essence taken in this way can be considered in two ways: in one way, according to its proper notion, and this is the absolute consideration of it. And in this way nothing is true of it except what belongs to it as such. Hence whatever else may be attributed to it, the attribution is false. For example, to man inasmuch as he is man there belong 'rational' and 'animal' and the other things that fall into his definition.

But 'white' or 'black,' or whatever of this kind, which is not of the notion of humanity, does not belong to man inasmuch as he is man. Hence, if it be asked whether this nature so considered can be called one or many, neither must be conceded, because each is outside the concept of humanity, and each can befall it. For if plurality belonged to its concept, it could never be one, whereas it is one according as it is in Socrates. Likewise, if unity belonged to its notion, then the nature of Socrates and of Plato would be one and the same, nor could it be multiplied in many.

In another way it is considered according to the being it has in this thing or in that, and in this way something is predicated of it accidentally, by reason of that in which it is, as when it is said that man is white because Socrates is white—although this does not belong to man inasmuch as he is man. Now this nature has a twofold being: one in singulars, and another in the soul; and according to each, accidents follow upon the said nature. And in singulars, too, it has manifold being according to the diversity of singulars; yet to the nature itself, according to its first consideration, namely the absolute one, none of these modes of being is owed.

For it is false to say that the essence of man, inasmuch as it is such, has being in this singular; because if being in this singular belonged to man inasmuch as he is man, he would never be outside this singular. Likewise, if it belonged to man inasmuch as he is man not to be in this singular, he would never be in it. But it is true to say that man, not inasmuch as he is man, has it that he be in this singular or in that, or in the soul. Therefore it is clear that the nature of man, considered absolutely, abstracts from every being, yet in such a way that no precision is made of any of them. And this nature, so considered, is what is predicated of all individuals.

Nevertheless it cannot be said that the notion of the universal belongs to the nature so taken, because to the notion of the universal pertain unity and community. But to human nature, according to its absolute consideration, neither of these belongs. For if community belonged to the concept of man, then in whatever humanity were found, community would be found. And this is false, because in Socrates no community is found, but whatever is in him is individuated. Likewise, neither can it be said that the notion of genus or species befalls human nature according to the being it has in individuals, because human nature is not found in individuals according to unity, such that there be one thing common to all, which the notion of the universal requires.

It remains, therefore, that the notion of species befalls human nature according to that being which it has in the intellect. For human nature itself has in the intellect a being abstracted from all individuating principles, and therefore it has a uniform relation to all the individuals that are outside the soul, inasmuch as it is equally the likeness of all and leads to the cognition of all, insofar as they are men. And from the fact that it has such a relation to all individuals, the intellect devises the notion of species and attributes it to it. Hence the Commentator says at the beginning of the De Anima that it is the intellect which produces universality in things. Avicenna too says this in his Metaphysics.

And although this understood nature has the notion of the universal according as it is compared to things outside the soul—because it is one likeness of all—nevertheless, according as it has being in this intellect or in that, it is a certain particular understood species.

And therefore the defect of the Commentator in Book III of the De Anima is evident, who wished to conclude, from the universality of the understood form, the unity of the intellect in all men; because the universality of that form is not according to this being which it has in the intellect, but according as it is referred to things as their likeness. Just as, likewise, if there were one bodily statue representing many men, it is clear that that image or species of the statue would have a singular and proper being according as it is in this matter, but would have the notion of community according as it were a common representation of many.