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.