11.3 Soul and Body in People (SCG 2,56–90)
11.3 Soul and Body in People (SCG 2,56–90)
I have noted that Aquinas does not take created intellect to be confined only to people. He thinks that angels are created intellects, and in SCG 2,91–101 he has several things to say about them. Before he discusses angels, however, in SCG 2,56–90 he has a lot to say about human beings and what intellect amounts to in them. These chapters consider a number of questions, yet by the time Aquinas has finished writing them he has presented an overall account of intellect in people that it would be good to grasp as a whole before working through some of its details. So, I shall now try to explain what that account basically has to say. Then I shall draw attention to some details to be found as Aquinas develops it.
11.3.1 Intellect and People: The Overall Account
As I have said, Aquinas does not think of human beings as totally immaterial things. He does not think that I am something that exists as a self-contained incorporeal substance, albeit one attached in some way to a body that I have. Descartes held that people, or the “selves” that people are, must be essentially immaterial, and he spoke of them as interacting with their bodies. On his account, what happens in my body can affect me in that, for example, my bodily sensations can lead me to know about things in the physical world. Again, on Descartes’s account, I can affect my body by, say, deciding to get my legs moving. Yet Descartes’s position is that I am not my body. For Descartes I am an essentially incorporeal and thinking thing.
Aquinas, by contrast, thinks it obvious that people are not incorporeal objects that are acted on by, and that can act on, bodies that they own or to which they are connected. Descartes ended up thinking of himself and others as he did because he thought it necessary to show that there are some things that we can certainly know to be the case, and he took the primary and incontrovertible truth to be “If I am thinking, then I exist, even if I do not have a body, as some skeptics have argued.” Descartes gets to the certainty that he exists while temporarily entertaining skeptical thoughts about the existence of bodies. Aquinas, however, has no doubts about the existence of bodies. He thinks it obvious that we live among physical things that act on us as much as we act on them. He thinks as a typical scientist does. Scientists would be out of business if they doubted the reality of a material universe. They take the reality of physical things for granted, and they see themselves as trying to understand such things and their ways of working. So Aquinas (rightly or wrongly) starts with what I suppose most of us would say: that there is a material world and that some of the things in it are human beings.
As I have said, however, Aquinas thinks that human beings have understanding. He holds that intellect can be ascribed to people.22 As I have also shown, he holds that understanding cannot be a process in something material. I may perspire out of fear when I see a tiger in front of me. Yet, thinks Aquinas, understanding what a tiger is cannot be a physical event, though it may follow such an event. As we might put it, to understand what a tiger is amounts to having formed a concept of something. Yet concepts in the mind cannot be physical replicas of that of which they are concepts. To understand what it is to be a tiger is to have the form (the whatness) of a tiger in one without being a tiger. Or so Aquinas thinks.
In his view, therefore, people exist in the material world, but they are also able to operate at a nonmaterial level because they have intellect. Indeed, thinks Aquinas, the human intellect is a subsisting immaterial thing, like any other intellect. On the other hand Aquinas does not want to say that people are just their intellects. He thinks that people are intellect plus body, the two making up a whole. Or, as Aquinas often says, people have both a body and a soul.
At this point you might suppose that in taking this view Aquinas is holding that a person is two distinct things yoked together somehow, as Descartes takes people to be. But that is certainly not what Aquinas maintains. He says that a living human being is a composite of soul and body. So he thinks of soul and body as essential parts of one thing: the living human being. Some religious people have spoken of the human soul as if it were a human being, the idea being that the person goes where the soul goes. For Aquinas, however, if my soul and body are separated, then I cease to exist since what I am is a human being, and a human being is a composite of soul and body. In that case, however, how does Aquinas view the relationship between body and soul in people? He argues that the human soul and body are related as form is related to matter.
Throughout his writings, Aquinas takes form to correspond to an account of what something is. And, as I have noted, Aquinas distinguishes between substantial forms and accidental forms. In Aquinas’s view substantial forms are primary while accidental forms are secondary. To specify something’s substantial form is to talk about what the thing is essentially; to specify something’s accidental forms is to talk about what something happens to be but can cease to be without ceasing to be what it is essentially. For Aquinas, therefore, something with an essence or nature has a substantial form to which accidental forms may be added or subtracted. And when Aquinas says that the human soul stands to the human body as form stands to matter as actualizing it in some way, he means that the human soul informs the human body as a substantial form informs anything bodily or material. Or, rather, he means something like that.
Here we need to note that when he is not talking about people (or about angels or God), Aquinas takes himself, when he is referring to substances, to be speaking about what is purely material: distinct physical things having a nature distinguishable from the individuals that they are. So he takes the world to consist of many material things having substantial forms that make them to be what they are. These forms, he thinks, are displayed in matter (in what can undergo substantial or accidental change without itself having form) but are not themselves material. They inform matter, and they are, in principle, shareable by different individuals. In holding to this position, Aquinas does not mean that, say, the substantial form of my cat is an independently existing nonmaterial thing. He means that my independently existing cat is made up of matter formed in a feline way, formed so as to constitute a cat, as opposed to a dog, or a crocodile, or whatever. Aquinas thinks that material things exist as displaying or having particular substantial forms that, so to speak, shape them. In this sense, says Aquinas, form gives being to what is material—not by creating it or by conferring some ethereal property called “being” to it but by constituting material things as different and existing things. So he thinks that for my cat to exist is just for it to be something feline, something with a feline nature, something having the substantial form of a cat.
Now, when it comes to material substances, Aquinas holds that substantial form informs matter just because the matter of material substances is formed in a certain way—meaning that form and matter in material substances are both material. Yet (1) he does not take this view when it comes to human beings. Nor (2) does he take it when it comes to living things in general. Since (2) here might seem to contradict what I have just been saying concerning Aquinas on form and matter, let me dwell on it a little before returning to (1).
As I noted in chapter 8, Aquinas takes all living things to have souls, to be animate as opposed to inanimate. Yet he also takes some living things (e.g., plants and cats) to be purely material, which leaves him with this question: Why are some material things animate while others are not? Aquinas thinks that, for example, cats are living things. But he does not think that stones are alive. So what makes cats different from stones when it comes to being alive? Aquinas’s answer is that cats have a principle of movement in them, unlike stones. And, he reasons, this principle cannot be a material thing, otherwise anything material would be a living thing. So, he says, the principle of life in a living yet material thing cannot be a body or a bodily part of something wholly material. It has to be the form of that material thing, which cannot itself be a material thing.
Aquinas, therefore, believes that even in wholly material living things there is a component that cannot just be described as a material thing. For that reason, it is, strictly speaking, wrong of me to have said that, for Aquinas, form and matter in material things are both material. Aquinas’s whole form/matter distinction is denying that form and matter are both material. On the other hand we also need to bear in mind that Aquinas does not think of purely material living things as being anything but material, which is why it is not totally misleading for me to say that form and matter in material things are, for Aquinas, both material. When Aquinas says that the principle of life in a wholly material living thing is not something bodily, he is not arguing that, say, plants are at some level spiritual or incorporeal. He is claiming that one cannot fully explain why they are alive by noting some physical bits of them, since if something physical were a principle of life (a soul or vital principle) it seems hard to understand why all physical or material things are not alive.
When it comes to people, however, Aquinas does believe that we are dealing with what is not purely material since he takes people to have intellect, and he thinks that substantial form in people is not something physical. As I have shown, Aquinas thinks that an intellect (any intellect, whether human, angelic, or divine) is immaterial, is not a form that depends for its existence on matter and must therefore subsist (exist as a thing). So when he tries to compare soul and body in human beings to form and matter in general, he is not committing himself to the idea that the human soul is entirely like the substantial form of a wholly material thing. He is regarding the principle of life in human beings (their substantial form or soul) as a subsistent immaterial thing. More precisely, he is thinking of the human soul as informing the body by acting in and through it.
Aquinas does not think that the human intellect is united to the human body by being mixed up with it as, say, tea leaves and hot water get mixed up so as to become a cup of tea. That is because he does not think of an intellect as something material. Tea leaves and water are material things that we can mix together. Yet Aquinas does not think that what is not material can be mixed with something material. Nor does he think that the human intellect can be united to the human body by bodily contact, as I can be united to you by, say, holding your hand. For, once again, Aquinas does not think of intellect as something corporeal. Yet he does think that there is something to note about how physical things connect with each other that provides a model for trying to figure out how an intellectual substance (an individual intellect) can be united to a body. The something in question here is the fact that one physical thing can act on something else and be active in the operation of the something else in question.
As I noted in chapter 3, Aquinas thinks that agent causes are at work in what they bring about. He does not think of an agent cause as different from its effect as, say, two billiard balls that bounce off each other are different from each other. Of course, he thinks that there is a distinction to be made between agent causes and their effects. Yet he also thinks that an agent cause is active in its effect. He thinks, say, that, when I am grooming my cat, my cat’s being groomed and my grooming my cat are not two actions but one action viewed from different points of view (that of the agent and the patient). I can cheerfully say “Well, it’s me that is grooming my cat, not someone else.” And my cat, if he could talk, might say, “Well, I am being groomed by Davies and not by anyone else.” Yet my grooming my cat and my cat being groomed by me are one and the same thing.
Here we have cause and effect united as one thing is working in or on another. And, thinks Aquinas, this is what we have when it comes to the human soul and what human bodies do as things with intellect. For Aquinas, the human soul, which is a subsisting intellectual thing, is united to the human body as acting in it, as governing its motions and reactions from beginning to end.23 Aquinas thinks that my body is moved by my soul (my intellect) without also thinking that I am my soul. In his view, my body, though often out of my control, is something that I need in order to exist as a human being. He also thinks that my voluntary bodily movements derive from my intellect and willing. Aquinas’s view is that people act by virtue of intellect, which, he says, is immaterial but able to produce effects in that to which it is united as subsisting form to existing matter.
Does all of this mean that Aquinas was a mind/body dualist, as Descartes is commonly taken to have been? In a sense, yes. But in a sense, no. Like Descartes, Aquinas sharply distinguishes between understanding, thinking, and willing (on the one hand) and the occurrence of bodily processes (on the other). Unlike Descartes, however, Aquinas does not think that he is an incorporeal mind or a thinking thing. Aquinas takes himself to be a human being and, therefore, something essentially bodily. And he thinks of his mind or intellect as a part of himself that accounts for what he does physically as something with intellect, something with will, something that can understand and make choices.
At this point, however, I should note that Aquinas does not just say that people have intellect. He says that they have an agent intellect (intellectus agens) and a receptive or possible intellect (intellectus possibilis). What does he mean by speaking in this way? He does not mean that the human intellect is an object consisting of parts as, say, an apple pie is something that is made up of both apples and pastry. Aquinas’s agent/receptive intellect distinction should be understood as comparable to the distinction we might make between a computer being able to deliver results that we are searching for and a computer being able to “remember” that for which we have been searching. But I offer this comparison only as an analogy since, as we know, Aquinas does not think of intellect as being something material, like a computer.
When saying that people have an agent intellect, Aquinas is not so much trying to explain what human understanding amounts to and how it arises as saying what has to be the case if human beings can understand what things are. I can understand that your cat and my cat are both cats. So it seems as though I can form a concept of “cat” without meaning, by my concept, what any individual cat is, considered as the individual material thing that it is. Or, so you might say, the meaning of a word cannot be an object that it names. Yet Aquinas thinks that knowledge in human beings arises on the basis of sensory experience. We are not, he believes, born with knowledge. We arrive, as it were, with a blank slate that needs to be written on as the world around us acts on us. This fact, however, leads Aquinas to ask how we can have knowledge expressible in sentences in which concepts and not individuals frequently feature.
If I know that cats have feline properties shared by all cats, then my knowledge seems to be knowledge of what things of a kind are, not just knowledge about some particular cat. The word “cat” is not the proper name of any cat, even if one might call one’s cat “Cat.” The word “cat” is used in sentences like “Sweetie is a cat” so as to assign Sweetie to a class of which there are many members. Yet a class of things is not a particular individual in the world with which we can interact, and if our knowledge arises on the basis of sensory experience of things, it seems natural to ask how we can move from contact with particulars to knowledge of what is not a particular individual. And, having raised this question, Aquinas replies that we do so not because of input from outside but because of the fact that we have an ability to abstract from particular things so as to form general concepts like “cat.”
It is in this connection that Aquinas speaks of us as having an “agent intellect,” an intellect that can process empirical data so as to be able to understand substantial and accidental forms in general. These, he thinks, exist, but only as possessed by particular material things. So, he argues, our intellect must have the ability to form concepts or ideas that are not particular material things. Hence the agent intellect. Or, as Anthony Kenny says, Aquinas’s position on agent intellect is this:
Substances in the physical world are in themselves only potentially thinkable, because they are individual and thought is universal. To make potentially thinkable objects into actually thinkable objects, we need an intellectual analogue of light in the visible world. And it is this intellectual analogue of light which is the agent intellect. One can think of the agent intellect as like the lantern a miner carries in his helmet, casting the light of intelligibility upon the objects a human being encounters in his progress through a mysterious world.24
Aquinas thinks of the agent intellect as an ability or capacity or power that belongs to individual thinkers. It is something that each of us has.25 And it is something that allows us to think abstract thoughts, to talk about things in general, and, therefore, to acquire what we might take to be scientific knowledge (which is never about particular material individuals but which groups things together so as to say, for example, that if you have a cat on your lap, then you have on your lap something the nature of which can be documented and understood by many people).
When it comes to receptive or possible intellect (intellectus possibilis), Aquinas thinks of this as our ability to retain what we have learned. I have learned loads of things in my lifetime, but I do not always call them to mind. Yet I can call at least some of them to mind, and I am obviously doing this as I speak and employ concepts. I have an ability to retain and employ concepts and beliefs that I have acquired over time. And it is this ability that Aquinas has in mind when he speaks of people having a “receptive intellect,” which he thinks of as a storehouse of ideas acquired over time. According to Aquinas, we do, in a sense, make the world that we live in because we have agent intellects. He does not mean that we create the world or that all that we know are ideas that we have formulated on the basis of sense experience. He thinks that we know a world that is there to be known because it acts on us physically so as to enable us to know about it. But he also thinks that things in the world leave traces in us, so to speak. So he thinks that, as the understanding things that we are, such traces exist in us to draw on as we continue to think. In short, he thinks that while our agent intellect allows us to form thoughts or concepts, our receptive intellect provides them with somewhere to live. Or, as Kenny says, reporting on Aquinas’s thinking about agent and receptive intellect, “If the function of the receptive intellect is as it were to provide room for thoughts, the function of the agent intellect is to provide furniture for that room, that is to create objects of thought.”26
11.3.2 Intellect and People: Some Details
All of the above ideas can be found in SCG 2,56–90, but they are sometimes presented by Aquinas while he is rejecting certain positions on the human intellect. For example, in SCG 2,57 and 58 he spends time trying to refute what he takes to be Plato’s view of soul and body, and in SCG 2,59–61, as well as SCG 2,73 and 75, he examines and rejects a series of arguments that he attributes to Averroes (1126–1198). Again, in SCG 2,62 and 76 we find Aquinas contradicting Alexander of Aphrodisias (fl. 200) concerning the receptive or possible intellect.27 Yet again, in SCG 2,63 Aquinas takes issue with Galen (130–200) while in SCG 2,74 and 76 criticizing Avicenna for saying that intelligible forms are not preserved in the possible intellect. At this point, however, I am not going to try to explain why Aquinas disagrees with the people I have just mentioned or what he takes them to have said.28 Instead, I shall briefly note points in SCG 2,56–90 at which we see emerging the general view on human intellect that I have noted above.
A critical text is SCG 2,56. Here we find Aquinas arguing that an intellectual substance, though not a body, can be united to a body by acting on it. He says:
Intellectual substances, being immaterial and enjoying a higher degree of actuality than bodies, act on the latter and move them. This, however, is not a contact of quantity, but of power. … The intellectual substance, then, can be united to a body by contact of power.29
Does contact like this make intellect and body just one thing when an intellect is united to a body? Aquinas goes on to argue in SCG 2,57 that it can if we think of an intellectual substance being the substantial form of a body. We read:
That by which something becomes a being in act from a being in potency is its form and act. But it is through the soul that the body becomes a being in act from being potentially existent, for living is the being of a living thing. Now the seed before animation is living only in potency, and, through the soul, becomes living in act. Therefore, the soul is the form of the animated body. In addition, since being as well as operating belong neither to the form alone, nor to the matter alone, but to the composite, to be and to act are attributed to two things, one of which is to the other as form to matter. For we say that someone is healthy in body and in health, and that they are knowing in knowledge and in their soul, knowledge being the form of the knower’s soul and health a form of the healthy body. Now, life and sensation are ascribed to both soul and body, for we are said to live and to sense both in soul and body. But we live and sense by the soul as the principle of life and sensation. The soul is, therefore, the form of the body.30
One might want to say that the soul has to be a body since there is nothing that is not a body, a position Aquinas turns to in SCG 2,65. Yet he distances himself from this conclusion. For example, he comments:
Since living things are physical realities, they are composed of matter and form. Now, they are composed of a body and a soul, which makes them actually living. Therefore, one of these two must be the form and the other matter. But the body cannot be the form, because the body is not present in another thing as its matter and subject. The soul, then, is the form, and consequently is not a body, since no body is a form. It is, moreover, impossible for two bodies to coincide. But, so long as the body lives, the soul is not apart from it. Therefore, the soul is not a body. … Also, the soul is separate from the body, not as a thing touching from a thing touched, but as form from matter, although, as we have shown [see SCG 2,56], that which is incorporeal does have a certain context with the body.31
Aquinas recognizes that some have argued that intellect and sense are the same and that intellect is, therefore, somehow bodily. Yet Aquinas insists that intellect and sense are very different. Lots of animals have sensation, he says, but they lack intellect, and sensation takes in particular things while intellect takes in what is intelligible and universal. He observes:
Sense is found in all animals, whereas animals other than man have no intellect. This is evident from the fact that the latter perform diverse and opposite actions, not as though they possessed intellect, but as moved by nature, carrying out certain determinate operations of uniform character within the same species. … Therefore, intellect is not the same as sense. Moreover, sense is cognizant only of singulars; for every sense power knows through individual species, since it receives the species of things in bodily organs. But the intellect is cognizant of universals. … Therefore, intellect differs from sense.32
When he speaks of nonhuman animals acting uniformly within a species (in eadem specie), Aquinas uses the word “species” as we would when saying, for example, that cats are a species of mammal, that they are mammals of a certain kind. But he is not using the word species (species) in this sense when he speaks of sense powers knowing through individual species (per species individuales). In the second use, Aquinas takes a species (which you should regard as a technical philosophical term in Aquinas’s vocabulary) to be what, in the present context, can be taken in by sensation, like the feeling hot arising from contact with something hot.33 And the point that he is making is that sensation is a physical effect of something particular acting on a body, while intellect grasps or takes in what is true of many things, even incorporeal ones. He means that, for example, I should not confuse my feeling of my cat on my lap with my understanding of what a cat is.
So, as I say, Aquinas’s view is that an intellect can be the form of a body, and that it is so when it comes to people. And having disposed, to his satisfaction, of arguments to the contrary in SCG 2,57–67, he reiterates his position in SCG 2,68–90 and makes these points:34
1. In people, soul is the “principle of the substantial being of the thing whose form it is.”35
2. In people, form and matter are joined in one act of being. A human being’s intellect and body make up a composite that is one thing: a human being.
3. Soul and body in people are distinct, though together they form one composite substance, and when separated from each other neither of them amounts to a human being.
4. The human soul is “on the horizon and confines of things corporeal and incorporeal in that it is an incorporeal substance and yet the form of a body.”36
5. In people, “body and soul are not two actually existing substances; rather the two of them together constitute one actually existing substance.”37
6. We can distinguish between the essence of the human soul and its powers. By its essence the soul makes a body to be a living body of a certain kind. By its power it performs certain operations that are bodily ones—as when it enables people to see with their eyes. Yet the soul’s power also extends to operations that do not depend on anything bodily—as when it understands. “The human soul is not a form wholly embedded in matter, but among all other forms occupies a most exalted place above matter. That is why it can produce an operation without the body.”38
7. If the soul is united to the body as its form, it is not united by some kind of intermediary. As the form of the human body, the soul, strictly speaking, is just what makes a human being to be what he or she is as a human being.
8. The whole soul is in the whole body and in each of its parts since the human soul is not just the soul of one bit of a human being but of the whole human being and “is, therefore, in the whole body, and not merely in one part, according to its essence whereby it is the body’s form.”39
9. There is no reason why the possible and agent intellect cannot exist together in the human soul since “nothing prevents one thing from being in one respect potential in relation to some other thing, and actual in another respect.”40
10. The human soul does not perish when the body perishes since it is not material and cannot, therefore, corrupt physically. “Every intellectual substance is incorruptible. But man’s soul is an intellectual substance, as was shown [see SCG 2,56–68]. It therefore follows that the human soul is incorruptible.”41 Aquinas refers to the soul continuing to exist after the death of a person as a “separated soul.”42
11. If a human being dies while his or her soul continues to exist, the soul in question, which is but a part of a human being, will not be able to function as it does when united to a human body. Human souls, as they inform living human bodies, gain knowledge by attending to things in the world around the bodies that they inform, which leaves them with impressions of material things.43 So, a human soul is not able to gain what we might think of as empirical knowledge if it does not exist as informing a human body. “It must be borne in mind that the soul understands in a different manner when separated from the body and when united to it. … Indeed, although the soul, while united to the body, enjoys absolute being not depending on the body, nevertheless the body is the soul’s housing (stramen), so to speak, and the subject that receives it.”44 Yet a human soul surviving the death of the body it once informed cannot lose its inherent ability to understand and to will.45
12. Nonhuman animals lack intellect, so their souls “are incapable of any operation that does not involve the body”; and “since every substance is possessed of some operation, the soul of a brute animal will be unable to exist apart from its body; so that it perishes along with the body.”46
13. “The human soul begins to exist when the body does.”47
14. The human soul is created by God and not made of God’s substance as some seem to have thought.48
15. The human soul is directly created by God since it begins to be yet is not something material and emerging from something that is material; it is not made from anything, so it is created by God and is not brought about by anything else.49