What arguments are there to think that we have a soul? There are some sophisticated arguments, but there are also very basic arguments. I intend to present some of the most basic arguments for the existence of the soul, and perhaps a word on its immortality, here.
The first and most accessible argument comes from the way we use language. We often make a distinction between ourselves, and the stuff we have. For instance we often say things like ‘this is my house’ or ‘these are my children’. We obviously intend a distinction between ourselves and the stuff which belongs to us. However, we don’t only use that language for our dearest possessions, but also of every part of our bodies, and our whole body. We say ‘this is my arm’ or ‘this is my body’ or even ‘I wish I had a different body’. Therefore this use of language evidences a deep awareness that we are not altogether merely a body, or else the statement ‘I wish I had a different body’ would be equivalent to, ‘I wish I were not myself’ (and though people say this, they usually mean that they wish they did not have such and such a vice, but the way I just used it goes far beyond such use).
Second we might take any argument from the failure of the materialist philosophy and metaphysics to count as arguments for the existence of the soul. This is so because the absurdities, especially the moral absurdities, which follow from materialism, would still apply to us if we and the world with which we interact were strictly material. Thus, even if angels existed, and God existed, if man were merely matter and the world with which man interacts were merely material then the same absurdities which result from wholesale materialism would apply.
A third argument can be adduced from the reality of (libertarian) free will, which is an irreducible part of the human experience. Given strong arguments for free will, on which I have already posted in the past, one must ask how free will could be possible. It seems to me that Free Will is only possible if the faculty which controls the actions of our bodies is not itself a part of our bodies (for then it would itself be subject to the passion of other parts of the body – or else other bodies altogether – acting upon it). Therefore, there must be something of us which is not physical which principally acts upon the body to do as it wills. Here perhaps one can even go further and do an analysis on the relationship of the body and the soul. They cannot be altogether different, such that the body is merely a vessel for the soul, for if the soul were not harmed by the actions of the body, then the soul would not be inhibited from action or thought by drunkeness or the like. However, the soul is greatly deprived of power to act or to think when the body suffers certain dispositions, and therefore the soul and the body must be somehow irreducibly attached. This is an argument adopted form St. Thomas Aquinas when he argued against a platonic view of the soul, and instead argued for a hylomorphic view (which remains the standard view of the Church).
Another argument might come from authority, and this argument can be broken into two parts (something Kreeft and Tacelli do in their book “handbook of Catholic/Christian Apologetics”). The first argument from authority is one from general consensus; most human beings both today and in recorded history have believed in the existence of the soul (some non-physical feature of the human person). Whatever most human beings believe and have believed is at least not unlikely to be true, and may in fact be likely to be true. The universality of the idea attests to it’s truth, since the idea is obviously not one of peculiar religious or philosophical invention (were it so, then its origin could be traced, but this idea has no traceable origin, since it seems to be believed by nearly everyone just about everywhere and since before we have records of human thought). The second argument is an argument from authority which runs something like this: all or most of the most intelligent people in the history of the world have believed in the Soul. A list could be made, but it would hardly ever be finished; (Socrates, Plato, Aristotle, Origen, Plotinus, Philo of Alexandria, Augustine of Hippo, Anselm, Leibniz, Aquinas, Bonaventure, Duns Scotus, William of Occam, Peter Abelard, Godel, Confucious, Ramanuja, Maimonides, Avicenna, and the list goes on and on). The argument would be that whatever most of the worlds greatest authorities (at least in the area of rational belief) believe is more likely to be true than not.
Another possible argument is an argument from Jesus Christ. Now, this splits into two arguments, the latter of which is stronger than the former. The first is from the authority of Jesus Christ himself, since he spoke on the matter and assumed a distinction between the body and the soul. This is a relatively weak argument, but notice it is only as weak or strong as the credence one gives Jesus of Nazareth – therefore for some the argument has incredible power to persuade, whereas for others the argument has absolutely no persuasive power – most people, I think, are probably somewhere in the middle, though likely unimpressed by this argument alone. The second argument is more forceful, as it comes from the resurrection. If the resurrection of Jesus of Nazareth happened, as good arguments seem to demonstrate, then the resurrection insinuates the existence of the soul in several ways. First, by way of Christianity’s being true, and it being an essential feature of Christian belief that the soul exists. Second, by way of the resurrection itself, which seems to make it more plausible that personal souls exist (since if man is nothing but the sum of physical parts then it is difficult to recognize Jesus’ identity over time after death – just because the body was miraculously put back in working order, and even retained memories or other features which the original Jesus had, would not make the resurrected Jesus the same person any more than cloning the original Jesus would have made a second Jesus (indeed, cloning anyone does not make a second ‘someone’). However, if the soul exists, then there is a way to identify the resurrected Jesus with the crucified Jesus.
Another argument comes from C.S. Lewis’ reflection on his wife’s death in ‘a grief observed’. He says “if she is not now then she never was – I mistook a cloud of atoms for a person”. This is perhaps one of the strongest arguments not only for the existence of the soul but for immortality – I highly recommend those not familiar with it to give the entire meditation a read (the whole thing will be more persuasive than my brief citation of it).
A seventh argument comes from the problem of identity. How can we identify individuals at all? For instance, if we say that the way we identify a person is by their body, so that where we see the same body we recognize the same person, there are various problems which present themselves. For starters, a teenager has not a single cell of his or her body remaining which was original to it as a newborn; but that suggests that any teenager is not the same person as the child who was born (thus this or that person was never born). If we say instead that we identify people by their DNA (which is something like the programming involved in retaining the ‘form’ of the body without retaining all or any of its parts/cells) then we must say that a perfect clone would introduce two of the same person into the world. However, this is absurd, since it is possible for one clone to kill another clone, or even the original (thus murdering herself). Moreover there certainly are seminal distinctions between the original and the clone(s) (for instance, that one is original and others are clones).
If we take a different rout, and decide to identify people based on their psychological disposition (meaning memory or temperament or some combination of the two), then we run into similar problems. For instance, if one’s mother has amnesia, and no longer remembers her child or that she even is a mother at all, is the person with amnesia really one’s mother, or a different person altogether? Most people will want to say that the person is the mother, and that they suffer from a disease called amnesia (there could be no diagnosis of such a disease without the assumption that the person is the same person as she was when she recognized herself to be a Mother). Moreover, personal temperament changed with age and experience, and sometimes changes drastically thanks to physical damage to the brain which cannot be anticipated by the study of genetics. There are only two ways to solve such difficulties; first, we give up on the idea that there are individual persons at all; second, that we identify people over time by something constant (thus not reducible to the body) which must be the soul.
That exhausts all the arguments off hand that I can think to give for the existence of the soul – I note again that these are not sophisticated arguments. The lack of sophistication is intentional; I intend only to present the relatively simple arguments to those readers who might benefit more from them then they would have from more complex arguments.