Lesson 5: The Immortality of the Soul

The human mind first grasps general truths about things and then progresses to more specific knowledge of them. So it is that, confronted with the realm of things that come to be as the result of a change, we first ask what can be said of things understood in that most general fashion. The least that one can say of the product of a change is that it is a combination of a subject and the characteristic acquired as the result of the change, a characteristic lacking in the subject prior to the change. This sweeping generalization applies to changes of quality and place and quantity, though insofar as "matter" is used for the subject and "form" for the new characteristic, we would first think of a qualitative change, a change of shape. To use "shape" or "form" in a generalized way can surprise, though perhaps the surprise is had by remembering the origin of the term rather than in its generalized use which of course is very familiar to us.

This account of the product of change does not obviously apply to a change whereby a subject would not just come to be in this respect or that -- quality, place, quantity -- but as such. That is, human beings undergo all kinds of changes, but they themselves are products of change and eventually will undergo a change after which they will be no more. Can the analysis of the product of change be applied to basic things, substances, themselves? Yes, by an analogy. This extension of the analysis to substantial change -- the change whereby basic things come into and pass out of existence -- is not meant to be a proof that such changes occur. We already hold that there are substantial changes. We know that there are basic things in the world and that they come into being and pass out of being. The preliminary analysis covered changes such things undergo once they have come to be. The analysis can be extended to substantial change so long as we take care to see that we are indeed extending it.

The subject or matter of the substantial change cannot itself be a substance. Why? A characteristic acquired by an existing substance does not make it to be as such, but to be in a certain respect. If then there is to be a change whereby a substance comes into being, we can say negatively that this subject cannot be a substance. This is signaled by calling it Prime Matter. Similarly, to underscore that the form acquired by Prime Matter results in a substance, we call it Substantial Form.

When we turn to living things, we bring along with us what has been said generally of physical objects. The analysis just recalled applies to every natural thing. But some natural things are alive. Therefore, it applies to them. But, as applied to them, it does not of course pick out what is distinctive to living things. What is distinctive to living things? We discriminate between the living and non-living physical objects on the basis of certain activities. Where these activities are present, we are in the presence of a living thing. Living things are the natural things that are capable of performing such activities. Among such vital activities are seeing and hearing. We would give different accounts of each. This living thing is capable of hearing and seeing; that is, sometimes it actually sees, something it could but its eyes are closed and it doesn't. Sometimes it actually hears, picking up a given sound, sometimes it picks up another sound. These capacities differ because when they are actuated we have activities which differ. The ability to see differs from the ability to hear. Now we are ready for Aristotle's first account of soul. "Soul is that whereby we first move, sense, think, imagine, etc." The soul is the substantial form of the living thing. To be alive is not like being here as opposed to there. It may be manifested by actually seeing or hearing, but these acts are episodic. Living is a substantial characteristic of certain natural things. The soul is simply the name used to designate the substantial form of such things.

As Aristotle's first definition suggests, our experience of life is not merely one of external observation. I am alive. This is something about which I am as certain as I can be. But my certainty is not generated by taking a peek at my soul, but by knowing that I am at the source of such acts as seeing, hearing, moving my hand, uttering complicated sentences and the like. My certainty that I myself am alive is one of the great presuppositions of this part of natural philosophy. My certainty of my own life combines internal and an external experience. I am capable of wiggling my fingers. I extend my hand and perform this feat. I am at one and the same time internally aware that I am doing this and I look at my wiggling fingers as what I am bringing about. It is on an analogy with this that I think that other entities that exhibit such external behavior have the interior wherewithal to engage in it.

Vital activities are the acts of powers or potencies. In the analysis of change, we can speak of the matter as potency and the form as act. Motion itself is the actuating of the potency. This is why we can apply to the analysis of vital activities the elements of the analysis of physical objects and the change that produces them. What happens when we think of seeing as coming to see and hearing as coming to hear and so on? Well, if there is a becoming there must be something that becomes and something that it becomes. The subject of the change will be the power of sight and the form will be color. From not seeing red, I come to see red. If the subject of the change has come to be red, we will find it important to distinguish this from the change whereby an apple, say, becomes red. When the apple becomes red, there is one more countable instance of redness in the world. When the eye sees red, this becoming red does not result in another countable instance of the quality redness. The distinction is marked by saying that, if the reception of the form in such a substance as an apple is for that form to be received in matter, then the reception of the form in sense perception can be denied to be the reception of the form in matter. When form is received in matter, when we have a physical change, the result is a new instance of the kind. This is not the case when the form is received in the sensing power. If the latter reception is called immaterial we can see that this arises from the negation and for the reasons given. It is also called an intentional change because redness as received by the power of sight is the means of seeing the red object. It tends toward the red object.

Now as it happens, the organ of sight can be the subject of change in the usual sense as well as subject of the change that is coming to see. The eye can become warm or cool, wet or dry. Moreover, a very bright light can render the eye momentarily blind. Thus, while the distinction between coming to see and physical change is clear enough, it is also clear that seeing involves a physical organ.

The Immateriality of Thinking

The use of "immaterial" to speak of sense perception is carefully controlled by the meaning of "material" that is being negated. There are different ways of having or receiving a form as the result of a process of change. When we think of thinking and its similarities and dissimilarities with sensing, a much stronger sense of "immaterial" is called for. To know what redness is, to have a concept of it, is to be able to give an account that, if accurate, is true of every instance of red such that "red" as signifying that concept can be predicated of any instance of the color. Universality is the mark of intellect.

Just as sensing involves a passage from a passive to an active state -- sensing is an intermittent activity -- so too thinking involves the actuation of a capacity which is not always operating, certainly not always thinking the same thing. In the case of sensation, it is the object that triggers the passage from potency to act. A red object in appropriate light causes us actually to see it. So too, if the intellect passes from potency to act, moving from being able to think to actually thinking, there must be some agent which brings about this change, an agent to produce the form in the mind. Material objects do not seem to suffice to bring this about. If they did, the change would be but another instance of a physical change, a cause bringing it about that a form is in matter.

One physical object can alter the temperature, change the place, increase the size of another, and the forms received as a result of the change are numerically different from the form as it is found in the cause. Sensation involves such a physical change, but cannot be reduced to it. When my hand touches the surface, there is a mutual alteration of temperature -- my hand cools as the surface warms. These are physical changes like any others. But feeling and an alteration of temperature are not identical: if they were, we would have to see that the book laid on the table feels the table and vice versa. Some philosophers and more science fiction writers have entertained this possibility but its entertainment value is limited. Such "sensation" would be a well-kept secret, exhibiting none of the concomitant features of sensation -- withdrawing before excessive heat, for example.

Sensation is the presupposition for thinking, not simply external sensing but the production of images by imagination and memory. Aristotle spoke of a common sense to account for the unified sensation of a physical object, one in which color and temperature, size, place, texture, etc. come together as this thing. These images are of singular things. Could they produce the idea?

The mark of intellection, as we have noted, is universality. We will consider the famous problem of universals in Lesson 10 below. For now, let it suffice to recall that it is a feature of our ideas that they range over individuals and they do this because they do not include individuating characteristics. "Man" can be predicated of Socrates and Euclid and Sophrosyne because the peculiarities of none of these humans are expressed by the concept the name signifies. They are not excluded in the sense of denied but -- as abstraction will be explained in Lesson 8 -- the nature is abstracted from them. This reception of the form -- when one comes to think Man, comes to know human nature -- will have the intellect as its subject and the nature plays the role of form. This is, of course, the source of the world "information", another proof for the Anti-Aristotelian Society that the great philosopher's theories have been smuggled into our languages. But of course the traffic goes in the other direction, and Aristotle is trying to articulate what we in some sense already know.

How does the reception of the form in sensation -- coming to see red -- differ from the reception of the form in understanding -- coming to know redness? One great difference lies in range. Sight is receptive of colors, hearing of sounds, and so with the other external senses; the internal common sense is the grasp of a colored, textured individual, with temperature, and so on. But for all that, the image of an individual, of this red thing. It is not simply that mind is receptive of redness. It is, as Aristotle wondrously remarked, receptive of anything and everything. "The mind is, in its way, everything." It was the pursuit of this spoor that led to the realization that thinking is an activity toto coelo different from sensing, let alone physical change, and involves not simply immateriality but spirituality.

The mind potentially knows and then actually knows. This is the change that leads to talk of the mind as subject and what it receives as a form. Physical objects as such cannot bring about this change, since there would be an obvious incommensurability between cause and effect -- a material cause, an immaterial effect. There must be some agency if this change is to occur, and it must like its effect be immaterial. There were those who thought this agent was some other being, a separated substance; there were those who thought this was Aristotle's view. What we do find is talk of intellect as the recipient of forms or ideas -- the receiving or passive intellect -- and of the intellect as agent. The same thing cannot be cause and effect, agent and patient, of the same change, so the two are indeed distinct -- the passive intellect, on the one hand, the agent intellect, on the other. It was the agent intellect some thought was an separated substance. Thomas proved, first, that this was not Aristotle's teaching and, two, that it leads to the impossibility of giving any straightforward account of "This man thinks." The upshot is that both agent and passive intellects are powers or faculties of the human soul.

Have we wandered too far from out primary concern? We set out to address the question of the immortality of the human soul. Some readers might think that we have become bogged down in esoteric discussions of concept formation and this may seem light years distant from the yearning that is often the antecedent to discussions of immortality. Is this all there is? Life is a wonderful thing, but it is short, even when it is long. The elderly speak with wonder of how short their long lives seem. Death is a horror and seems a definitive end, yet it seems part of human nature to think beyond the grave, to anticipate a continued existence as if unable to imagine that life should simply and completely end. It is not that the running down of the body surprises, so much as the distinctive human activities. The creative imagination, the ranging intellect. These capacities enable us to contain our container, so to speak. Speck though he may be from a cosmic point of view, man's intellect soars out into space, negating distances, encompassing the whole.

That is the lived background against which such analyses as we have sketched take place. To some degree, we are simply seeking to make explicit what is implicit in the experiences just described. There are, needless to say, questions that arise from the preliminary account of the immateriality of intellect we have put forward. A philosophical account is always put forward in readiness to take objections to it. But I will end with a thought experiment.

Imagine undertaking the task of proving that thinking is just a physical event. Material. Nothing more. There are philosophers committed to this view. Their work lies all before them. As they will acknowledge, we do seem to have "two languages," one for physical objects, another for mental events. The algorithm that would enable us to transpose mental object talk into physical object talk has not been found. Materialism is a project, not an established position. Those who stick with the project through thick and thin, who acknowledge the obstacles to it and renew their faith in the eventual triumph of materialism, make clear that they are operating from an antecedent belief or hunch. They are antecedently sure that the material is all there is. Any indication that this is not so, must be explained away. It is well, when the difficulties involved in arguing for the general sense of mankind that death is not the end, to remind oneself that the opposite position has even more troubles. Sometimes I think that the dogged devotion to materialism is the most profoundly existential refutation of it.

Suggested Reading Assignment

In the Penguin Selected Readings you will find a selection devoted to Thomas's commentary on the opening chapters of Book Two of Aristotle's De anima.

Suggested Writing Assignment

Show how the analysis of physical coming-to-be is used and extended to talk about coming-to-see, coming-to-hear, etc.


You might want to look at Aquinas against the Averroists: On there being only one intellect, my translation of the De unitate intellectus published by Purdue University Press, 1993. This text defends his interpretation of Aristotle against that of the Averroists. The edition contains a number of interpretative essays.


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