What I have argued so far is that without a functioning brain, the soul will not function (i.e. have conscious episodes)—not that it will not exist. But what does it mean to suppose that the soul exists at some time without functioning? The distinction between existence and functioning is clear enough in the case of a material substance, which has some sort of life (e.g. a plant) or some sort of working (e.g. a machine). The substance continues to exist so long as the matter of which it is made continues to exist in roughly the same shape (with the possibility perhaps of gradual replacement of parts). But it functions only so long as normal life-processes or machine-use continue. The clock exists, when it no longer tells the time, so long as the parts remain joined in roughly the normal way; and a dead tree is still a tree, although it no longer takes in water through its roots and sunlight through its leaves.
The distinction is not, however, at all clear in the case of the soul, an immaterial substance. The soul functions while it is the subject of conscious episodes—while it has sensations or thoughts or purposes. But is it still there when the man is asleep, having no
conscious episodes? This calls for a decision of what (if anything) we are to mean by saying of some soul that it exists but is not functioning.
We suppose that persons continue to exist while asleep, having no conscious life. In saying that some such person still exists, we mean, I suggest, that the sleeping body will again by normal processes give rise to a conscious life, or can be caused to give rise to a conscious life (e.g. by shaking it), a conscious life which by the criteria of Chapter 9 will be the life of the person existing before sleep. Now, we could describe this latter fact by saying that, although persons only exist while they are conscious, the bodies which they previously owned continue to exist during the periods of unconsciousness and become thereafter the bodies of persons again (indeed the same persons who previously owned those bodies). However, that would be a very unnatural way to talk, largely because it has the consequence that certain substances (persons) are continually popping in and out of existence. Although there seems to me nothing contradictory in allowing to a substance many beginnings of existence, it seems a less cumber-some way to describe the cited fact to say that persons exist while not conscious, and mean by this that normal bodily processes or available artificial techniques can make those persons conscious. This will have the consequence that persons normally have only one beginning of existence during their life on Earth.
Our grounds for saying that persons exist while not conscious are similar to the grounds which I gave in Chapters 6 and 7 for saying that persons have desires and beliefs when they are not aware of them, i.e. that they can easily be made aware of them and that those desires and beliefs will influence their actions when they are put in appropriate circumstances.
Conscious persons consist of body and soul. We could say that souls exist only while conscious; while a person is asleep, his soul ceases to exist but it is made to exist again when he is woken up. But this would be a cumbersome way of talking. It is better to understand by a soul existing when not functioning that normal bodily processes on their own will, or available artificial techniques can, make that soul function. In saying this I am laying down rules for the use of a technical term, ‘soul’. With this usage, a soul exists while its owner exists; and a soul will normally have only one beginning of existence during a man's life on Earth.
But the boundaries of this usage are not as clear as they look. It all depends on what we understand by ‘normal’ bodily processes and ‘available’ artificial techniques. If a drowned body of a person can be revived by artificial respiration, that person certainly exists before the respiration is given. And the same perhaps goes for the man rendered unconscious through injury who will not become conscious again except by use of the latest techniques available to the best doctors. But what about the man in a coma for reviving whom there are no techniques available to doctors at that place and time, though there will be such techniques usable a few years later? Are there, then, ‘available’ techniques? If the man's body is kept alive, it is unlikely that he will recover spontaneously, but it is possible. If he recovers, have ‘normal processes’ made his soul function again? Shall we say that a normal bodily process ‘can’ make a man's soul function, revive that soul, only if it leads to revival almost invariably, or is it enough that occasionally it shall lead to revival? Any spelling out of what constitutes ‘normal’ bodily processes, or ‘available’ techniques will bring out how arbitrary a matter it often is whether we say that some person exists, although unconscious; or whether we say that he does not exist although perhaps may be caused again to exist. However, if we are to bring precision and consistency into our talk of this matter, we must, I think, develop the account which I have given so far by giving fairly arbitrary stipulative definitions of ‘normal’ bodily processes and ‘available’ techniques. If our talk of persons existing is not to depart too wildly from ordinary usage, we must deny that it is sufficient for the existence of a man merely that it is logically possible that he be brought to life again; for in that case all dead men would continue to exist (as a mere logical consequence of once having existed). And if we are to keep our talk about souls in line with our talk about men, we must not say this of souls either. I suggest that we understand in this context by a bodily process being ‘normal’, that it will yield its outcome with a high degree of predictability given normal nutrition, respiration, etc., without sophisticated medical intervention; and by a technique being ‘available’, that it is available to doctors during that period of history within a region of the size of the average county. Alternative definitions are possible of what it is for a person and so his soul to exist, when not conscious, but I do not think that they
will prove any less arbitrary than the suggested one. (Any definition in terms of it being naturally or physically possible, for some agent at some time or place, to revive the person runs into the difficulty that there may not be any general laws connecting the physical and the mental—as I shall argue later in the chapter, and so one cannot know what is physically possible in general, only what is practically possible under certain familiar circumstances.) My preferred definition does allow that it sometimes happens that a person (and so his soul) ceases to exist and then by an unexpected accident comes to exist again. It thus allows a substance to cease to exist and then to come into existence a second time; but I cannot see any good reason for not talking in that way. What this discussion will, I hope, have brought out is that little turns on whether some soul exists unfunctioning (e.g. after death). The real issue is just how easy it is to get it to function again.
So, given that the soul functions first about twenty weeks after conception, when does it come into existence? There exist normal bodily processes by which the fertilized egg develops into a foetus with a brain after twenty weeks which gives rise to a functioning soul. If the soul exists just because normal bodily processes will bring it one day to function, it surely therefore exists, once the egg is fertilized, at conception.98 On the other hand one might say that normal
processes need to be fairly speedy ones if the soul is to exist during their operation; and so that the soul begins to exist, only shortly before it first begins to function. Once again it seems an arbitrary matter when we say that the soul begins to exist, requiring a further stipulation as to how ‘normal bodily processes’ are to be understood. It seems to me somewhat more natural to describe things in the second way. What is important, however, is to keep clear the factual and conventional elements involved in claiming that the soul comes into existence at a certain time.99
98 But not before conception, since the union of the two cells at fertilization constitutes a sharp break, and is hardly a normal process analogous to growth.
99 That the human soul (the rational or intellectual soul as the medievals called it) comes into being (connected to the body) sometime between conception and birth is the
traditional Catholic doctrine. The human soul is present when there is specifically human functioning. In the last century or two it has been normal for Catholic writers and pronouncements to assume that that soul comes into being at conception. St Thomas Aquinas on the other hand held that the fertilized egg began to grow first as an animal (or, alternatively, first as a living non-conscious thing and then as an animal), and only later as a human; that is, it was animated first by a sensitive soul (or first by a vegetative soul and then by a sensitive soul) and only later by an intellectual soul (see Summa Theologiae, Ia, 76. 3, ad 3 and IIa, IIae, 64. 1). Aquinas owed this view to Aristotle. It was listed as an error by Pope Leo XIII in 1887 (H. Denzinger, Enchiridion Symbolorum, 1910 ). Aquinas would not have denied that abortion was wrong, even when (because done soon after conception) it was not the killing of a human being and so murder. He would have said that it was still wrong in virtue of being the destruction of a potential human being, or the frustration of a natural process. Aquinas's view that the foetus is animated by a human soul only at some time much later than conception, seems to have been a general view in the Western Church until the nineteenth century—see G. R. Dunstan, ‘The Moral Status of the Human Embryo: A Tradition Recalled’, Journal of