In A Brief History of the Soul Stewart Goetz and Charles Taliaferro provide a robust argument against the doctrine that humans are nothing more than atoms and molecules. The authors mine the Western philosophical tradition to sketch a sophisticated account of what it means to be an embodied, immaterial soul. This account is then tested against modern objections. The text is always interesting and enlightening; however, in many ways it is an extended version of the third chapter of Naturalism (Eerdmans: 2008) by the same authors, and should be read in conjunction with that book.
A Brief History of the Soul finds three main arguments for proposition that we have immaterial minds. First, Goetz and Taliaferro’s draw on an observation that was first made by Augustine. In every conscious moment I am aware of numerous, irreducibly different states of affairs. I can be simultaneously aware of the location of my body, the colors on a computer screen, a pain in my lower back, the smell of coffee, a sweet taste, beliefs about the nature of consciousness, a decision to type something about these beliefs, a desire to write something meaningful, frustration at my lack of progress and much else besides.
Now, note that we experience all these things as one fact. We have “unity of consciousness”: one subject co-experiences various sensations, beliefs, desires and thoughts all at once. This experience is radically different from our brains and nervous systems, which are open to “third person, public” observation and measurement. Your first-person awareness of the world cannot be observed or fully known by anyone but you. Furthermore, our experiences cannot be quantified or measured. Many cannot be adequately captured by art or literature; so pity the fool who tries to devise a unit for measuring melancholy or joy!
The brain processes a scene when populations of sensory cells cut it into chunks of information that can processed by millions and millions of cells deep in the cortex. Yet we do not experience numerous interacting parts; instead we experience one coherent image. This image is so rich that one artist could render one scene in numerous styles and still not exhaust everything that he had been aware of. We can dissect nerves and brains into their various spatial parts; yet, while we can direct our attention to one part of our stream of consciousness, we cannot dissect our awareness for study. The qualities that characterise experience (like sensation and intentionality) are not the properties that characterise physical parts (like mass and energy).
It seems that our unity of consciousness cannot be identical to anything in the physical world. It is true that we can surprised when two seemingly unrelated events or objects turn out to be identical. A medieval astronomer might have speculated that the evening star and morning star were in fact the same heavenly body; a good mystery writer can have his amnesiac protagonist discover that he is the murderer. But we can see how a detective could be a murderer, and how different lights in the sky could be caused by one planet. The properties essential to being a unified conscious experience and the properties essential to being a physical system are so radically different they simply cannot be the same thing.
Not only do we have a unified conscious awareness of numerous facts; we also seem to be selves that endure through time. We can remember past experiences – and, as Thomas Reid (1710-1796) pointed out, our memories are not subjectless. We do not merely recall the fact that a certain event happened to us; we remember our experiences from our own subjective perspective. Every memory includes a reference to the “I” who is remembering. This unity of our psychological lives is best explained if we are enduring selves.
Second, Taliaferro and Goetz draw attention to the teleological explanations of human action found in Aristotle and Aquinas. These differ in nature from scientific explanations. In a scientific explanation of personal actions, events in the person’s brain cause the person to act. The person is passive in these explanations– physical events in the brain do all the causal work. But in an teleological explanation the person is active, not passive. The person assesses his desires and beliefs and then makes an undetermined choice for a particular purpose.
In a teleological explanation a person’s choice is not dictated by events that occur in the brain or the environment. The agent is free to choose from a course of action. So the agent must have a power to choose in a teleological explanation. For teleological explanations to be true, there must more to us than the physical parts that make up our bodies; we must have non-physical minds that have some level of control over our actions. Otherwise we would not be able to escape the chain of physical causes and effects. Free-will would be an illusion in such a world – yet we experience ourselves as free agents, and a robust account of moral responsibility demands that we have such freedom.
The third argument concludes that we must have a substantial non-material part because we are rational beings. Materialism assumes that the physical world is causally closed: every physical event has another physical event as its sufficient cause. When we explain physical events (such as events in the brain or the human body) we should only appeal to physical forces, physical objects and the laws that govern them. We would be able to fully explain the words and actions of humans merely by appealing to the operation of the brains physical parts. This has an unusual consequence – we do not need to appeal to any event in a human’s subjective consciousness to explain their actions or words!
Even if some physical events are somehow identical with mental events (and it is impossible to see how this could be so) it is the physical structure of the events in the brain that will determine what we report and how we act. The psychological and conceptual content of an experience has no causal power at all; remember, the materialist believes that a chain of physical cause and effects governs all our behaviour. On materialism, the processes in my brain are the contingent outcome of evolution by natural selection. This process did not aim at true belief – it merely favoured brain events that promoted survival and reproduction.
Psychologists have routinely tried to demonstrate that certain beliefs are not rational because they are produced by causal chains that are not aimed at truth. For example, Freud argued that our belief in God and the beliefs produced by conscience are not rational. So, if I hold beliefs simply because the molecules in my brain have interacted in a certain manner, I have good reason to doubt my beliefs. But this can’t be right! Surely when I accept the rationality of a belief, it is because I grasp that belief’s content and the connection between that belief and other beliefs.
Of course, this is not an argument against evolution or even for theism. It merely establishes that materialism cannot give an adequate account of rationality because it cannot explain why our beliefs can match reality. If we are rational then mental events – like beliefs and decisions – must be able to cause some events in the physical world; mental content cannot be irrelevant to behaviour. Rationality also demands that we are substantial selves that persist through time. A rational inference is not the output of a chain of non-rational events in a physical system. To make a good inference one subjective awareness must grasp the content of numerous beliefs and the rational connections between them.
So what exactly is this soul, which experiences, thinks and acts? The authors depart from Descartes, who identified the soul with thought. Instead, they prefer to define the soul as a simple substance, capable of thought, sensation and action. They cite Thomas Reid approvingly. “I am not thought, I am not action, I am not feeling; I am something that thinks and acts and suffers. My thoughts and actions and feelings change every moment – that have no continued, but a successive, existence; but that self, or I, to which they belong is permanent …” (p119)
Perhaps we can put this in a simpler form: a soul is rational, purposive power. In the right circumstances it can be the subject of experiences and act upon the world. In the case of human souls, this requires that the soul be in a relationship with a body. The author’s spend some time discussing how the soul is related to the body – they seem attracted to views that locate the soul spatially within the body. They note that there is nothing in contemporary physics that demands that the propensities of particles be actualized by other physical objects. If the soul has causal power, the capacity of a micro-particle to act in a certain way could be actualized by an immaterial mind.
The authors note that all causality is mysterious, and so it should not concern us that the interaction of an immaterial mind (the soul) and a material body seems puzzling. At this stage, the authors could have drawn on the world described by modern physics. Once we have comprehended the sheer weirdness of the quantum world, it is rather easy to accept bodies could interact with immaterial minds. Science might not find the idea of a rational, purposive, immaterial substance very respectable. But modern physics has taught us that reality is not that bothered by what we find respectable. The truth will often be stranger than atheist fictions.
That said, the authors make the important point that the soul is not an hypothesis that attempts to account for scientific observations. Plato, Augustine, Descartes, Butler and Reid merely reported what they were directly acquainted with when they reflected on their own conscious experience. They just seemed to be – and we seem to be – enduring, rational selves. If we are mistaken about the deep matters of the self, it is difficult to see how we could depend on any other observation. Materialism struggles to account for our first person experience because it must explain this evidence away. Little wonder, then, that the authors recommend the more robust and rational worldview of theism.
Apologetics 315 Book Reviewer Graham Veale is Head of Religious Education at City of Armagh High School. With David Glass, he runs the apologetics group Saints and Sceptics. Their articles can be read at www.saintsandsceptics.org
 Alternatively, “desires” or “beliefs” might do all the causal work in a psychological explanation. Even then, the agent is caused to act by psychological events. He does not choose a course of activity for some purpose.