Aquinas: On Being and Essence - Chapter 4

Chapter Four

ESSENCE AS FOUND IN SEPARATE SUBSTANCES

[1] It remains for us to see how essence exists in the separate substances: in souls, intelligences,†1 and the first cause. Although everyone admits the simplicity of the first cause, some would like to introduce a composition of form and matter in intelligences and souls,†2 an opinion that seems to have begun with Avicebron, the author of The Source of Life.†3 But this is opposed to what philosophers generally say; they call these substances separated from matter and prove that they are completely immaterial.†4 This is best demonstrated from their power of understanding.†5 We see that forms are actually intelligible only when they are separated from matter and its conditions; and they are made actually intelligible only through the power of an intelligent substance, by receiving them into itself and acting upon them.†6 That is why every intellectual substance must be completely free from matter, neither having matter as a part of itself nor being a form impressed on matter, as is the case with material forms.

[2] The position is untenable that not all matter prevents intelligibility but only corporeal matter. If this resulted only from corporeal matter, matter would have this opaqueness to understanding from its corporeal form, since matter is called corporeal only because it exists under a corporeal form. This is impossible, because this corporeal form, like other forms, is actually intelligible insofar as it is abstracted from matter. In a soul or intelligence, therefore, there is no composition of matter and form, understanding matter in them as it is in corporeal substances. But there is in them a composition of form and being.†7 That is why the commentary on the Book of Causes says that an intelligence is that which has form and being;†8 and by form is here understood the quiddity itself or simple nature.

[3] It is easy to see how this is so. Whenever things are so related to each other that one is the cause of the other's being, the one that is the cause can have being without the other, but not vice versa. Now matter and form are so related that form gives being to matter. Matter, then, cannot exist without some form, but there can be a form without matter: form as such does not depend on matter. If we find some forms that can exist only in matter, this happens to them because they are far removed from the first principle, which is the primary and pure act. It follows that those forms closest to the first principle are forms subsisting in themselves without matter. In fact, not every kind of form needs matter, as has been said; and the intelligences are forms of this kind. There is no necessity, then, that the essences or quiddities of these substances be anything else than form.

[4] The essence of a composite substance accordingly differs from that of a simple substance because the essence of a composite substance is not only form but embraces both form and matter, whereas the essence of a simple substance is form alone. Two other differences follow from this. The first is that we can signify the essence of a composite substance as a whole or as a part. This happens because of the designation of matter, as has been said.†9 As a result we do not attribute the essence of a composite in every way to the composite; we cannot say, for example, that man is his quiddity. But the essence of a simple reality, which is its form, can only be signified as a whole, because nothing is there beside the form as its recipient. That is why the essence of a simple substance, no matter how we conceive it, can be attributed to the substance. As Avicenna says, "The quiddity of a simple substance is the simple entity itself," because there is nothing else that receives it.†10

[5] The second difference is that the essences of composite things, by being received in designated matter, are multiplied according as it is divided. From this it happens that there are things the same in species and different in number. But since the essence of a simple entity is not received in matter, it cannot be multiplied in this way. That is why in these substances we cannot find many individuals in the same species; there are as many species among them as there are individuals, as Avicenna expressly says.†11

[6] Substances of this kind, though pure forms without matter, are not absolutely simple; they are not pure act but have a mixture of potentiality. The following consideration makes this evident. Everything that does not belong to the concept of an essence or quiddity comes to it from outside and enters into composition with the essence, because no essence can be understood without its parts. Now, every essence or quiddity can be understood without knowing anything about its being. I can know, for instance, what a man or a phoenix is and still be ignorant whether it has being in reality.†12 From this it is clear that being is other than essence or quiddity, unless perhaps there is a reality whose quiddity is its being. This reality, moreover, must be unique and primary;†13 because something can be multiplied only [1] by adding a difference (as a generic nature is multiplied in species), [2] by the reception of a form in different parts of matter (as a specific nature is multiplied in different individuals), [3] by the distinction between what is separate and what is received in something (for example, if there were a separated heat,†14 by the fact of its separation it would be distinct from heat that is not separated). Now, granted that there is a reality that is pure being, so that being itself is subsistent, this being would not receive the addition of a difference, because then it would not be being alone but being with the addition of a form. Much less would it receive the addition of matter, because then it would not be subsistent, but material, being. It follows that there can be only one reality that is identical with its being. In everything else, then, its being must be other than its quiddity, nature, or form. That is why the being of the intelligences must be in addition to their form; as has been said,†15 an intelligence is form and being.

[7] Whatever belongs to a thing is either caused by the principles of its nature (as the capacity for laughter in man) or comes to it from an extrinsic principle (as light in the air from the influence of the sun). Now being itself cannot be caused by the form or quiddity of a thing (by 'caused' I mean by an efficient cause), because that thing would then be its own cause and it would bring itself into being, which is impossible.†16 It follows that everything whose being is distinct from its nature must have being from another. And because everything that exists through another is reduced to that which exists through itself as to its first cause, there must be a reality that is the cause of being for all other things, because it is pure being.†17 If this were not so, we would go on to infinity in causes, for everything that is not pure being has a cause of its being, as has been said. It is evident, then, that an intelligence is form and being, and that it holds its being from the first being, which is being in all its purity; and this is the first cause, or God.

[8] Everything that receives something from another is potential with regard to what it receives, and what is received in it is its actuality. The quiddity or form, therefore, which is the intelligence, must be potential with regard to the being it receives from God, and this being is received as an actuality. Thus potency and act are found in the intelligences, but not form and matter, except in an equivocal sense.†18 So, too, 'to suffer', 'to receive', 'to be a subject', and all similar expressions which seem to be attributed to things because of matter, are understood in an equivocal sense of intellectual and corporeal substances, as the Commentator remarks.†19

[9] Because, as we have said,†20 the quiddity of an intelligence is the intelligence itself, its quiddity or essence is identical with that which it is, while its being, which is received from God, is that by which it subsists in reality.†21 That is why some say that a substance of this kind is composed of 'that by which it is' (quo est) and 'that which is' (quod est),†22 or, according to Boethius, of 'that which is' (quod est) and 'being' (esse).†23

[10] Since there is both potency and act in the intelligences, it will not be difficult to find a multitude of them, which would be impossible if they had no potentiality. That is why the Commentator says †24 that if the nature of the possible intellect were unknown, we could not find a multitude of separate substances. These substances, moreover, are distinct from one another according to their degree of potency and act, a superior intelligence, being closer to the primary being, having more act and less potency, and so with the others. This gradation ends with the human soul, which holds the lowest place among intellectual substances. As a result, its possible intellect bears the same relation to intelligible forms that primary matter, which holds the lowest position in sensible being, bears to sensible forms, as the Commentator says.†25 That is why the Philosopher compares the possible intellect to a blank tablet on which nothing is written.†26 Having more potentiality than other intellectual substances, the human soul is so close to matter that a material reality is induced to share its own being, so that from soul and body there results one being in the one composite, though this being, as belonging to the soul, does not depend on the body.†27 After this form, which is the soul, there are found other forms which have more potentiality and are even closer to matter, to such a point that they do not have being without matter. Among these forms, too, we find an order and a gradation, ending in the primary forms of the elements, which are closest to matter. For this reason they operate only as required by the active and passive qualities and other factors that dispose matter to receive form.