All of a sudden the soul is back in fashion. Thirty years ago it had been so banished from polite society that even Bible translators tried to avoid using it. Now it has bounced back with such vigour that the Times newspaper no less has a weekly supplement titled 'Body and Soul'.
Should SoF members welcome this development? Will it help our efforts to explore and promote religious faith as a human creation? The answer is No if it signals a return to the discredited model of the human person as a 'ghost in the machine', or if it reflects intellectually sloppy New Age superstition. Both these dangers need guarding against. But explored against the best current research into human consciousness, the rehabilitation of the soul offers an opportunity to revisit some old theological language that could yield useful new insights into the nature of personhood.
A Brief History of the Soul
The ancient Hebrew understanding of a human being focused on what we think of as the body: a living person was a live body, animated by an impersonal 'breath of life', and a dead person was a dead body, lacking the breath of life. I say 'what we think of as the body' because there is no word in Hebrew for 'body' in contrast to 'mind' or 'soul', in the modern sense. Instead there are different words signifying the whole human person under different aspects, such as vitality or mortality. It is a holistic view.
This is in stark contrast to the dualist teaching of the ancient Greek philosopher Plato. For him the non-physical soul constituted the essence of a human being: a living person was an embodied soul, and a dead person was a disembodied soul; the physical body was just a temporary lodging.
These two approaches are sometimes referred to simply as Hebrew and Greek, but that is to over-simplify. Another influential Greek, Plato's pupil Aristotle, used the word 'soul' to denote the functional structure or 'form' of living things. On this understanding, the soul related to the organization and function of the physical body; it was not composed of matter, but it could not exist independently of matter.
Christianity is heir to the approaches of the Hebrew Bible, of Plato, and of Aristotle, but its most formative period - the fourth and fifth centuries A.D. - saw Plato's influence in the ascendant. So the classic Christian debates concerning humankind and God, which focused on the person of Jesus Christ, were conducted on the assumption that the essential person is a non-material soul temporarily inhabiting a physical body. This posed a problem for early theologians trying to understand the relation between the human and the divine in Jesus. Was his physical body inhabited and directed by both a human soul and the divine Word of God? And if so, how could he be a single fully integrated person? But if not, how could he be both fully human and fully divine?
The failure to answer these questions satisfactorily led to divisions in the Church that exist to this day, but one formula was accepted by the great majority. This proposed that Jesus (1) had a rational soul associated in the usual way with his body making him one human, and (2) had the Word of God associated in a precisely equivalent way with his total humanity (soul and body) making him one Christ. We shall return to this formula below.
Meanwhile St Thomas Aquinas in the thirteenth century set himself the task of reconciling this Platonic Christian teaching with the then newly-rediscovered philosophy of Aristotle. By now the claim that the human soul was immortal and lived on after the death of the body had long been official Church teaching, despite its apparent conflict with the Bible, which with its Hebrew pedigree spoke of the afterlife as the holistic resurrection of the body, rather than the dualistic immortality of the soul. Aquinas brought together in one system the contradictory views presented by Plato, Aristotle, and the Bible, and the synthesis he achieved forms the backdrop to all modern study of consciousness and personhood.
St Thomas kept to Aristotle's definition of the soul as the 'form' of a living organism, apart from which it was unable to exist. He taught that when a plant or animal died and ceased to exist physically, its soul also ceased to exist. But humans were different, because their souls - uniquely among all creatures - were rational, which meant they engaged in thinking. Aquinas noted that intellectual activity was unlike anything that plants or animals did, because it was not in itself a bodily process. Anything done by a plant - taking up water, growing, wilting, producing flowers, etc. - was a process bringing about a change in the plant's physical state. In the same way, anything done by an animal - feeding, moving, fighting, breeding, etc - involved a change in the animal's body. So it followed that the governing principle of both plants and animals, their soul, had no role apart from the physical organism with which it was associated. But humans were different. They could think. And so far as Aquinas could tell, thinking - that is, things like imagining, deciding, planning, etc. - involved no necessary bodily process or change. So unlike the situation with plants and animals, in humans the governing principle - the rational soul - did have a role over and above that of directing the body and its organic processes. This gave Aquinas the opening he needed. If the rational soul could do things that did not directly bring about changes in the body, then it was not entirely nonsensical (as it would have been in the case of plants and animals) to think of that soul as continuing in existence even after the body had died and been destroyed.
But this raised a problem. According to Aquinas's way of thinking, a soul that was produced naturally along with its body (like those of plants and animals) would also be subject to the natural process of death and decay. So if the human soul really could survive bodily death, then God must have directly created it outside the natural course of events. The problem was that now this rational soul was being thought of in Aristotle's way (rather than as a Platonist's free-floating spirit), it was not clear how it could exist in isolation from the body.
The brilliant Aquinas turned this difficulty into an opportunity that enabled him both to reconcile Aristotle with the Church's official teaching and also to resolve a tension in Christian teaching between the bodily resurrection found in the Bible and the immortality of the soul inherited from Plato. The rational soul, said St Thomas, must be able to maintain some kind of existence without a body, but it would be a very unsatisfactory state for it to be in. It would not be able to do anything except think, because it still needed a body in order to receive information through the senses, to express itself, to act, to communicate with others, and so on and so forth. What the rational soul needed, in short, was to be reunited with its body after death in order to restore the whole person. Here, then, was the explanation, lacking in the Platonist version of Christianity, for the resurrection of the body. It would be the occasion for the restoration of the full person by the reuniting of the body and soul of those who had died.
Brilliant as Aquinas's synthesis was, it did not satisfy everyone. René Descartes in the seventeenth century declared it had been a mistake to suppose the rational soul (i.e., the thinking mind) and the physical body were bound together by some kind of necessity. If the rational soul could really function - even temporarily and unsatisfactorily - when it was cut off from the bodily senses, then however close the working relationship between them, body and soul must each exist quite independently of the other. In particular, it was the mind and not the body that constituted the person, the human subject, the 'I' of whom Descartes famously said, 'I think, therefore I am.' This declaration marked the watershed between the later Middle Ages and the Enlightenment. Quite simply Descartes dispensed with the more holistic approaches of the Bible and Aristotle and returned to a mind-body dualism much more like that of Plato and the fifth-century Church.
The Soul Today
Descartes' dualist view was dominant for the next 300 years, and could still be named by Oxford philosopher Gilbert Ryle in the middle of the twentieth century as 'the official doctrine' of philosophy of mind. But that was all about to change. Ryle himself led the assault on 'the dogma of the ghost in the machine', as he dubbed it: 'It is,' he wrote, 'entirely false, and false not in detail but in principle. It is not merely an assemblage of mistakes. It is one big mistake.'
In its place, there were proposed various theories affirming the essential unity of physical and mental aspects of a person. These approaches are called physicalist (or materialist) because they give priority to a person's body, and claim that all mental states (thinking, believing, deciding, etc.) can be given a physical explanation. Some versions of materialism simply equate the mental and physical aspects of a person; others say that although the mind derives from the body, and is ultimately dependent on it, the mind cannot be identified 'without remainder' with the body alone - there is more to it than that.
I am going to consider just the second of these approaches, and in particular the theory known as emergence. Emergence - broadly defined - says that when physical entities reach a certain level of organisational complexity, there emerge genuinely new properties such that the whole is more than the sum of its parts. It appeals to many studying the nature of personhood, because it offers a bridge between those for whom everything is ultimately physical and those for whom there is an irreducible mental or spiritual component of reality that is essentially non-physical.
The paradigm example of emergence is the liquidity of water. A single H2O molecule cannot be described as liquid or as wet; the water I drink from a glass is both wet and liquid, yet consists of nothing but H2O molecules. Liquidity and wetness are not added ingredients to water, they are 'emergent properties' of it. For American philosopher John Searle, the conscious mind of a person is best understood in a comparable way as a causally emergent feature of the brain. The person (or mind or soul) is not an added ingredient to the physical body, but neither is it present in any individual brain cell. Like the liquidity of water, it is an emergent property.
On this understanding, the conscious mind has its origins in the physical brain, but is not simply the same thing as the brain. Having emerged from the physical body, but without any added ingredients, it exhibits new features over and above the sum of its parts. It takes on an existence of its own, which is more than just the subjective experience of the person concerned, and it has a legitimate place in the external world of bodies and events. But it cannot be altogether divorced from its physical basis.
Human and Divine Personhood
Now what happens when we apply this model of human being to the formula from the early Church concerning the person of Christ? The first part said that Jesus had a rational soul associated in the usual way with his body making him one human. The formula's authors assumed that Jesus' human soul was a non-physical entity existing independently of his body, but we are assuming - on the emergence model - that his human mind (soul, person) arose from the complex physiology of his body, especially his brain and nervous system. So far so good. What about the second part of the old formula? That said that in the person of Christ, the Word of God was associated with Jesus' total humanity (soul and body) in a precisely equivalent way to that in which his human soul was associated with his body. Applied to our new understanding of human nature, this means the divine element in Christ is now to be understood as an emergent property.
That is to say: just as Christ's human mind - and indeed any human mind - arose from the complex physiology of his body, especially his brain and nervous system, so his divinity arose from the complex system which was his total humanity - body, mind, soul, consciousness. In other words: just as the mind or soul is not an added ingredient to the human body, but an integral emergent property of it, so Christ's divinity is not an added ingredient to his human person, but an integral emergent property of it. And the Christian tradition says that what is true of Christ's divinity is true of God absolutely.
John Searle uses the formula 'caused by and realised in' to explain the relation between an emergent property of a system and the lower-level elements that make up the system. Liquidity is a higher-level property caused by and realised in H2O molecules; human consciousness - human personhood - is a higher-level property caused by and realised in the physical structure of the brain and nervous system. By extension I am suggesting that 'God-consciousness' - divine personhood - is a higher-level property still, caused by and realised in the physical-and-mental-totality of human beings.
Anthony Freeman
Anthony Freeman is a priest in the Church of England. He has been managing editor of the Journal of Consciousness Studies since 1994.
For more background and discussion of the ideas contained in this article, see: