文集 第 4 章

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.

And because to human nature according to its absolute consideration it belongs that it be predicated of Socrates, while the notion of species does not belong to it according to its absolute consideration, but is among the accidents that follow upon it according to the being it has in the intellect, therefore the name of the species is not predicated of Socrates, so that it should be said: 'Socrates is a species'—which would necessarily happen if the notion of species belonged to man according to the being he has in Socrates, or according to his absolute consideration, namely inasmuch as he is man. For whatever belongs to man inasmuch as he is man is predicated of Socrates. And yet to be predicated belongs to the genus per se, since it is placed in its definition.

For predication is something that is completed through the action of the intellect composing and dividing, having its foundation in the thing itself in the unity of those things, one of which is said of the other. Hence the notion of predicability can be enclosed within the notion of this intention which is the genus, which likewise is completed through an act of the intellect. Nevertheless, that to which the intellect attributes the intention of predicability, composing it with another, is not the intention of genus itself, but rather that to which the intellect attributes the intention of genus, as is that which is signified by this name 'animal.'

Thus, therefore, it is clear in what manner the essence or nature stands in relation to the notion of species: namely, that the notion of species is not among those things which belong to it according to its absolute consideration, nor is it among the accidents which follow upon it according to the being it has outside the soul, such as whiteness and blackness, but it is among the accidents which follow upon it according to the being it has in the intellect; and in this same manner the notion of genus or of differentia also belongs to it. [V] Now it remains to see in what manner essence exists in separated substances, namely in the soul, the intelligence, and the first cause.

Now although all concede the simplicity of the first cause, nevertheless certain men strive to introduce a composition of form and matter into the intelligences and into the soul; the author of which position seems to have been Avicebron, the author of the book The Fount of Life. But this is commonly repugnant to the sayings of the philosophers, who call those substances separated from matter and prove them to be without any matter. The most powerful demonstration of this is from the power of understanding which is in them. For we see that forms are not actually intelligible except according as they are separated from matter and its conditions;

nor are they made actually intelligible except through the power of an understanding substance, according as they are received in it and according as they are acted upon by it. Hence it is necessary that in every understanding substance there be an utter immunity from matter, such that it neither has matter as a part of itself nor even is, as it were, a form impressed in matter, as is the case with material forms. Nor can anyone say that it is not just any matter that impedes intelligibility, but only corporeal matter.

For if this were by reason of corporeal matter only, then—since matter is not called corporeal except according as it stands under a corporeal form—it would follow that matter would have this, namely to impede intelligibility, from the corporeal form. And this cannot be, because the corporeal form itself is also actually intelligible, just as the other forms are, according as it is abstracted from matter. Hence in the soul or in the intelligence there is in no way a composition of matter and form, such that essence be taken in them as in corporeal substances; but there is in them a composition of form and being.

Hence, in the commentary on the ninth proposition of the Book of Causes, it is said that an intelligence is something having form and being; and there 'form' is taken for the quiddity itself, or the simple nature. And how this is so is plain to see. For whatever things are so related to one another that one is the cause of the being of the other, that which has the notion of cause can have being without the other, but not conversely. Now such is found to be the relation of matter and form, because the form gives being to matter. And therefore it is impossible for matter to be without some form. Nevertheless it is not impossible for some form to be without matter.

For a form does not, in that which it is as form, have a dependence on matter; but if certain forms are found that cannot exist except in matter, this befalls them according as they are distant from the first principle, which is the first and pure act. Hence those forms which are nearest to the first principle are forms subsisting through themselves without matter (for a form does not, according to its whole genus, need matter, as has been said), and forms of this kind are the intelligences. And therefore it is not necessary that the essences or quiddities of these substances be anything other than the form itself.

In this, therefore, the essence of a composite substance and that of a simple substance differ: that the essence of a composite substance is not form alone, but embraces both form and matter, whereas the essence of a simple substance is form alone. And from this two other differences are caused. One is that the essence of a composite substance can be signified either as a whole or as a part, which happens on account of the designation of matter, as has been said. And therefore the essence of a composite thing is not predicated in just any way of the composite thing itself; for it cannot be said that man is his own quiddity. But the essence of a simple thing, which is its form, cannot be signified except as a whole, since there is nothing there besides the form, as it were receiving the form;

and therefore in whatever way the essence of a simple substance is taken, it is predicated of it. Hence Avicenna says that the quiddity of a simple thing is the simple thing itself, because there is nothing else receiving it. The second difference is that the essences of composite things, from the fact that they are received in designated matter, are multiplied according to its division, whence it happens that certain things are the same in species and diverse in number. But since the essence of a simple thing is not received in matter, there cannot be there such a multiplication; and therefore in those substances there cannot be found several individuals of the same species, but as many as there are individuals there, so many are there species, as Avicenna expressly says.

Substances of this kind, therefore, although they are forms alone without matter, nevertheless do not have an all-encompassing simplicity in themselves, nor are they pure act, but they have an admixture of potency. And this is plain thus. For whatever is not of the concept of the essence or quiddity is something coming from outside and making a composition with the essence, because no essence can be understood without those things which are parts of the essence. But every essence or quiddity can be understood without anything being understood about its being; for I can understand what a man is, or what a phoenix is, and yet be ignorant whether it has being in the nature of things.

Therefore it is clear that being is other than essence or quiddity—unless perhaps there be some thing whose quiddity is its very own being; and this thing cannot be other than one and first, because it is impossible that there be a multiplication of anything except through the addition of some differentia, as the nature of a genus is multiplied into species; or through this, that a form is received in diverse matters, as the nature of a species is multiplied in diverse individuals; or through this, that one is absolute and the other received in something—as, if there were a certain separated heat, it would be other than non-separated heat by its very separation.

But if there be posited some thing which is being alone, such that being itself be subsistent, this being will not receive the addition of a differentia, because then it would no longer be being alone, but being and besides this some form; and much less would it receive the addition of matter, because then it would be not subsistent but material being. Hence it remains that such a thing, which is its own being, cannot be other than one. Hence it is necessary that in every other thing besides it, its being be one thing and its quiddity, or nature, or form, be another. Hence it is necessary that in the intelligences there be being besides the form; and therefore it has been said that an intelligence is form and being.

Now everything that belongs to something is either caused from the principles of its own nature, as the capacity for laughter in man, or comes to it from some extrinsic principle, as light in the air from the influence of the sun. But it cannot be that being itself be caused by the very form or quiddity of a thing—I mean as by an efficient cause—because then a thing would be the cause of itself, and a thing would produce itself in being, which is impossible. Therefore it is necessary that every such thing, whose being is other than its nature, have its being from another. And because everything that is through another is reduced to that which is through itself as to a first cause, it is necessary that there be some thing which is the cause of being for all things, in that it is being alone.

Otherwise one would proceed to infinity in causes, since every thing which is not being alone has a cause of its being, as has been said. It is clear, therefore, that an intelligence is form and being, and that it has its being from the first being, which is being alone. And this is the first cause, which is God. Now everything that receives something from another is in potency with respect to that, and that which is received in it is its act. It is necessary, therefore, that the quiddity or form itself, which is the intelligence, be in potency with respect to the being which it receives from God; and that received being is by way of act. And thus potency and act are found in the intelligences, yet not form and matter, except equivocally.

Hence also to suffer, to receive, to be a subject, and all such things, which seem to belong to things by reason of matter, belong equivocally to intellectual and to corporeal substances, as the Commentator says in Book III of the De Anima. And because, as has been said, the quiddity of an intelligence is the intelligence itself, therefore its quiddity or essence is that very thing which it is, and its being, received from God, is that by which it subsists in the nature of things. And on this account such substances are said by some to be composed of 'that by which it is' and 'that which is,' or of 'that which is' and 'being,' as Boethius says. And because in the intelligences there is posited potency and act, it will not be difficult to find a multitude of intelligences;

which would be impossible if there were no potency in them. Hence the Commentator says in Book III of the De Anima that, if the nature of the possible intellect were unknown, we could not find a multitude in separated substances. There is therefore a distinction of them from one another according to the degree of potency and act, such that a higher intelligence, which is nearer to the first, has more of act and less of potency, and so on with the rest. And this is completed in the human soul, which holds the lowest rank among intellectual substances. Hence its possible intellect stands to intelligible forms as prime matter, which holds the lowest rank in sensible being, stands to sensible forms, as the Commentator says in Book III of the De Anima.

And therefore the Philosopher compares it to a tablet on which nothing is written. And because, among the other intellectual substances, it has more of potency, therefore it is rendered so near to material things that a material thing is drawn to participate in its being—namely in such a way that from soul and body there results one being in one composite, although that being, inasmuch as it is the soul's, is not dependent on the body. And therefore after this form, which is the soul, there are found other forms having more of potency and nearer to matter, so much so that their being is not without matter. Among these too there is found order and degree, down to the first forms of the elements, which are nearest to matter.

Hence they have no operation except according to the requirement of the active and passive qualities and the others by which matter is disposed toward form. [VI] These things, therefore, having been seen, it is clear in what manner essence is found in diverse things. For a threefold mode of having essence is found in substances. For there is something, namely God, whose essence is His very own being; and therefore certain philosophers are found saying that God has no quiddity or essence, because His essence is nothing other than His being.

And from this it follows that He is not in a genus, because everything that is in a genus must have a quiddity over and above its existence, since the quiddity or nature of a genus or species is not distinguished, with respect to the formal account of the nature, in those things of which it is the genus or species, whereas existence is diverse in diverse things. Nor is it necessary, if we say that God is existence alone, that we should fall into the error of those who said that God is that universal existence by which each and every thing formally is. For this existence which God is, is of such a condition that no addition can be made to it; hence by its very purity it is an existence distinct from every other existence.

On account of this, in the commentary on the ninth proposition of the Book of Causes it is said that the individuation of the First Cause, which is existence alone, is through its pure goodness. Now common existence, just as it does not include any addition in its intelligible notion, so neither does it include in its notion the precluding of addition; for if this were so, nothing could be understood to be an existence in which something might be added over and above existence. Likewise also, although it is existence alone, it does not follow that the remaining perfections and nobilities are lacking to it; rather, it possesses all the perfections that are in all the genera. On account of this it is called perfect simply, as the Philosopher and the Commentator say in Book V of the Metaphysics.

But it possesses them in a mode more excellent than all things, because in Him they are one, whereas in other things they have diversity. And this is so because all those perfections belong to Him according to His simple existence; just as, if someone could by a single quality produce the operations of all the qualities, he would possess all the qualities in that one quality, so God in His very existence possesses all perfections. In a second way essence is found in created intellectual substances, in which existence is other than their essence, although the essence is without matter.

Hence their existence is not absolute but received, and therefore limited and finite to the capacity of the receiving nature; but their nature or quiddity is absolute, not received in any matter. And therefore it is said in the Book of Causes that the intelligences are infinite below and finite above. For they are finite as regards their existence, which they receive from a higher source, yet they are not bounded below, because their forms are not limited to the capacity of any matter receiving them. And therefore in such substances there is not found a multitude of individuals in one species, as has been said, except in the human soul, on account of the body to which it is united.

And although its individuation depends occasionally on the body as regards its inception, since individuated existence is acquired for it only in the body of which it is the act, nevertheless it is not necessary that, when the body is taken away, the individuation should perish; because, since it has absolute existence from the moment that individuated existence was acquired for it by the fact that it was made the form of this body, that existence always remains individuated. And therefore Avicenna says that the individuation or multiplication of souls depends on the body as regards its beginning, but not as regards its end.

And because in these substances quiddity is not the same as existence, they are therefore capable of being ordered within a predicament; and on this account there is found in them genus and species and difference, although their proper differences are hidden from us. For even in sensible things the essential differences themselves are unknown, whence they are signified by accidental differences which arise from the essential ones, as a cause is signified by its effect, just as two-footed is posited as the difference of man. But the proper accidents of immaterial substances are unknown to us; hence their differences can be signified by us neither in themselves nor through accidental differences.

This, however, must be known: that genus and difference are not taken in the same way in these substances and in sensible substances; for in sensible things the genus is taken from that which is material in the thing, while the difference is taken from that which is formal in it. Hence Avicenna says, at the beginning of his book On the Soul, that in things composed of matter and form the form is the simple difference of that which is constituted from it—yet not in such a way that the form itself is the difference, but because it is the principle of the difference, as the same author says in his Metaphysics. And such a difference is called a simple difference, because it is taken from that which is a part of the thing's quiddity, namely from the form.

But since immaterial substances are simple quiddities, in them the difference cannot be taken from that which is a part of the quiddity, but from the whole quiddity; and therefore at the beginning of On the Soul Avicenna says that only those species have a simple difference whose essences are composed of matter and form. Likewise also in them the genus is taken from the whole essence, yet in a different manner. For one separate substance agrees with another in immateriality and they differ from one another in the degree of perfection according to recession from potentiality and approach to pure act. And therefore from that which follows upon them insofar as they are immaterial, the genus in them is taken, such as intellectuality or something of this kind.

But from that which follows upon their degree of perfection, the difference in them is taken, though it is unknown to us. Nor must these differences be accidental, because they are according to greater and lesser perfection, which does not diversify the species. For the degree of perfection in receiving the same form does not diversify the species, as whiter and less white in participating a whiteness of the same nature. But a diverse degree of perfection in the very participated forms or natures does diversify the species, just as nature proceeds by degrees from plants to animals through certain things which are intermediate between animals and plants, according to the Philosopher in Book VII of On Animals.

Nor again is it necessary that the division of intellectual substances should always be through two true differences, because this is impossible to occur in all things, as the Philosopher says in Book XI of On Animals. In a third way essence is found in substances composed of matter and form, in which both the existence is received and finite—on account of the fact that they have existence from another—and again their nature or quiddity is received in designated matter. And therefore they are finite both above and below, and in them, on account of the division of designated matter, a multiplication of individuals in one species is already possible. And how in these the essence is related to the logical intentions has been said above. [VII].

Now it remains to see how essence exists in accidents. For how it exists in all substances has been said. And since, as was said, essence is that which is signified by the definition, it follows that accidents must have essence in the way in which they have a definition. But they have an incomplete definition, because they cannot be defined unless a subject is placed in their definition. And this is so because they do not have existence in themselves, absolute from a subject; but just as from form and matter substantial existence is left when they are composed, so from accident and subject accidental existence is left when an accident comes to a subject.

And therefore neither does the substantial form have a complete essence, nor does matter; because even in the definition of the substantial form there must be placed that of which it is the form; and thus its definition is by the addition of something which is outside its genus, just as also is the definition of an accidental form. Hence in the definition of the soul the body is placed by the natural philosopher, who considers the soul only insofar as it is the form of a physical body. Yet between substantial and accidental forms there is this much difference: that just as the substantial form does not have absolute existence in itself without that to which it comes, so neither does that to which it comes, namely matter.

And therefore from the conjunction of both is left that existence in which the thing subsists in itself, and from them is produced something one in itself; on which account from their conjunction a certain essence is left. Hence the form, although considered in itself it does not have the complete account of essence, is nevertheless a part of the complete essence. But that to which an accident comes is a being complete in itself, subsisting in its own existence. This existence indeed naturally precedes the accident which supervenes.

And therefore the supervening accident, from its conjunction with that to which it comes, does not cause that existence in which the thing subsists, through which the thing is a being in itself, but it causes a certain secondary existence, without which the subsisting thing can be understood to exist, just as what is first can be understood without the second. Hence from accident and subject there is not produced something one in itself, but something one by accident. And therefore from their conjunction there does not result a certain essence, as from the conjunction of form to matter. On which account an accident has neither the account of a complete essence nor is it a part of a complete essence; but, just as it is a being in a qualified sense, so too it has an essence in a qualified sense.

But because that which is said most fully and most truly in any genus is the cause of those things which come after in that genus—just as fire, which is at the limit of heat, is the cause of heat in hot things, as is said in Book II of the Metaphysics—therefore substance, which is first in the genus of being, having essence most truly and most fully, must be the cause of accidents, which secondarily and as it were in a qualified way participate in the account of being. This, however, comes about in diverse ways. For since the parts of substance are matter and form, certain accidents follow principally upon form and certain ones upon matter. Now some form is found whose existence does not depend on matter, such as the intellectual soul;

matter, however, does not have existence except through form. Hence among the accidents which follow upon form, there is something which has no communication with matter, such as understanding, which is not effected through a bodily organ, as the Philosopher proves in Book III of On the Soul. But some of those that follow upon form are such that they do have communication with matter, such as sensing. But no accident follows upon matter without communication of form. In these accidents, however, which follow upon matter, a certain diversity is found.

For some accidents follow upon matter according to the order it has to a special form, such as masculine and feminine in animals, whose diversity is reduced to matter, as is said in Book X of the Metaphysics. Hence, the animal form being removed, the said accidents do not remain except equivocally. But some follow upon matter according to the order it has to a general form, and therefore, the special form being removed, they still remain in it; just as the blackness of skin is in the Ethiopian from the mixture of the elements and not from the account of the soul, and therefore after death it remains in them.

And because each thing is individuated by matter and is placed in a genus or species by its form, therefore the accidents which follow upon matter are accidents of the individual, according to which even individuals of the same species differ from one another; whereas the accidents which follow upon form are the proper passions either of the genus or of the species; hence they are found in all that participate in the nature of the genus or species, just as 'capable of laughter' follows in man upon his form, because laughter occurs from some apprehension of the human soul. It must also be known that accidents are sometimes caused by the essential principles according to a perfect act, such as heat in fire, which is always actually hot;

but sometimes only according to an aptitude, while the completion happens from an external agent, such as transparency in air, which is completed through an exterior luminous body. And in such cases the aptitude is an inseparable accident, but the completion, which comes from some principle that is outside the essence of the thing or that does not enter into the constitution of the thing, is separable, such as being moved and the like. It must also be known that in accidents genus, difference, and species are taken in a different way than in substances.

For because in substances, from the substantial form and matter there is produced something one in itself by a certain single nature resulting from their conjunction—which is properly placed in the predicament of substance—therefore in substances the concrete names which signify the composite are properly said to be in a genus, as species or genera, such as 'man' or 'animal.' But neither form nor matter is in a predicament in this way except by reduction, just as principles are said to be in a genus. But from accident and subject there is not produced something one in itself. Hence there does not result from their conjunction any nature to which the intention of genus or species could be attributed.

Hence accidental names said concretely are not placed in a predicament as species or genera, such as 'white' or 'musical,' except by reduction, but only according as they are signified in the abstract, such as 'whiteness' and 'music.' And because accidents are not composed of matter and form, therefore in them the genus cannot be taken from matter and the difference from form, as in composite substances; but the first genus must be taken from the very mode of being, according as being is predicated in diverse ways, according to prior and posterior, of the ten genera; just as quantity is named from the fact that it is the measure of substance, and quality according as it is a disposition of substance, and so of the others, according to the Philosopher in Book IX of the Metaphysics.

But the differences in them are taken from the diversity of the principles by which they are caused. And because the proper passions are caused by the proper principles of the subject, therefore the subject is placed in their definition in the place of a difference, if they are defined in the abstract according as they are properly in a genus, just as it is said that snubness is the curvature of a nose. But it would be the reverse if their definition were taken according as they are said concretely. For thus the subject would be placed in their definition as a genus, because then they would be defined after the manner of composite substances, in which the account of the genus is taken from matter, just as we say that the snub is a curved nose.

It is likewise also if one accident is the principle of another accident, just as the principle of relation is action and passion and quantity; and therefore the Philosopher divides relation according to these in Book V of the Metaphysics. But because the proper principles of accidents are not always manifest, therefore sometimes we take the differences of accidents from their effects, just as 'gathering together' and 'scattering apart' are called differences of color, which are caused by the abundance or scarcity of light, from which diverse species of colors are caused. CONCLUSION:

Thus, therefore, it is clear how essence exists in substances and in accidents, and how in composite and in simple substances, and in what way in all these the universal logical intentions are found—except in the First, which is at the limit of simplicity, to which the account of genus or species does not belong, and consequently neither does definition, on account of its simplicity. In Whom may there be the end and consummation of this discourse. Amen.