The Evolution of the Soul. Mind, Brain and Free Will updates his arguments for dualism. The book is refreshingly clear, rigorously argued and a joy to read.
Swinburne argues that physical events and conscious events – beliefs, desires, thoughts, purposes and sensations – are not identical. To put that another way, the terms we use to pick out physical events, and the terms we use to pick out mental events, never refer to the same thing. We need to think a little about words and concepts here – after all, we cannot say much about the world without them! Anyone who knows what terms like “red” or “pain” mean knows how to use them. They know exactly what it is to have a sensation of red or a pain. They know how when and how to apply the terms, and can make simple inferences using the terms. (For example we can infer “it is a sensation” and “it is unpleasant” from “it is a pain.”)
Some terms, however, do not get at the essence of what they designate; we don’t fully understand what is involved in their application. Early explorers could see a mountain from Tibet which they identified by its shape and called "Everest". At the same time, other explorers in Nepal could see a mountain with a different shape which they called "Gaurisanker". However, it soon became apparent that the two mountains were identical – it was the same mountain viewed from different perspectives. "Gaurisanker" and "Everest" actually referred to the same rocky matter. Of course, this did not surprise early geographers - after all, they were only referring to superficial appearances, and not what underlay those appearances.
Obviously, there are certain things that simply could not be identical. For example, explorers could never discover that the Nile and Everest referred to the same geographical features. It is also clear that mental properties and physical properties are not identical. “Reflecting light at such and such a wavelength” does not entail “red” or “blue” – that is, it does not logically entail how that reflected light will appear to observers.
Suppose I put my hand to close to a flame and receive a burn. I feel pain, referring to a particular unpleasant sensation. Such a feeling is uniform and simple, and it impresses itself directly on my consciousness. Observers could infer that I was in pain from my behaviour. However, I don't need to infer that I am in pain by observing my behaviour or brain states; I feel it directly. As Swinburne puts it, I have privileged access to mental events like pain. It is this mental property that I refer to when I say I feel “pain”. I am picking out an experience, describing the property as it appears “on the surface.” I am not picking out a physical event which causes that experience.
The criteria for being a “pain” and its underlying brain state are different. We know what the term "pain" refers to without any knowledge of the underlying brain state. "Pain" refers to a specific, simple sensation. The physical events associated with pain are anything but simple. If I describe the complex sequence of neurological events that accompanies that pain, and the specific function that the pain plays in moving my body away from harm, and even the set of physical events that the pain "represents", I leave something important out: that simple, specific sensation that makes pain what it is.
We can informatively designate the feelings of pain and heat without knowing anything about physics or biology. We can also informatively designate behaviour and brain states without knowing anything about the accompanying sensations (we do not know “what it is like” for rodents to feel fear or for sea snails to feel pain). It follows that mental states and physical states are not identical. It also seems that mental states do not necessitate particular physical states. There seems no reason to believe that a being with a different neuro-physiology or neuro-anatomy – like an artificially intelligent robot, or a silicon-based life form - could not feel sensations like pain.
Some properties of physical objects are entailed by their underlying physical structure. In these cases we can see how the properties of the whole follow from the properties of the parts. So if we had sufficient knowledge of its chemical structure and the underlying physics, we could predict that frozen water would float on liquid water. But nothing about a brain’s underlying physical properties seems to entail a particular conscious experience. In fact, the underlying physical structure of our bodies does not entail that we should feel anything at all. There is absolutely nothing about the interaction physical parts that would allow us to predict the emergence or character of a conscious experience. We rely on the testimony of subjects and our own experience to know what is occurring in other minds.
Swinburne goes on to argue for “substance dualism” - the unfashionable view that human beings are an immaterial soul or mind. The basis for substance dualism is surprisingly clear. Sometimes conscious events overlap. Consider the experience of being burned by a flame. If it is possible to experience heat, light and pain simultaneously, one subject must experience all three sensations. Furthermore, this one subject must persist through time. I can feel a pain that lasts for one second, and hear a noise that commences 0.5 seconds after I first felt the pain. This noise might continue for ten seconds, but overlap with an experience of a taste that endures for the last five seconds of the noise. Swinburne argues that "[w]hen two conscious events overlap, they are events of the same substance; the overlap entails this." It is evident, then, that we are mental substances who endure for longer than the specious present.
David Hume famously claimed that we have no idea of the self because, when we introspect, we do not have an impression of the self. All we find are perceptions and sensations. Hume claims "I never find myself at any time without a perception". Hume was correct. We never experience "ourselves" unless we are experiencing some conscious event or other. But that does not imply that all I can experience is disconnected conscious events! What I am aware of are numerous conscious events experienced in a common subject – me! I experience and think about everything from one point of view – my own.
Our theories about reality should be tested by experience. We should not begin with our theories and reject experiences that do not fit. Contemporary physicalists tend to reject mental phenomena because they do not fit with their materialistic metaphysics. Swinburne argues that “it is an unavoidable datum of experience” that we are immaterial selves who exercise causal influence on our bodies. He also argues that there is a fundamental epistemic Principle of Credulity foundational to all inquiry.
The Principle of Credulity simply states that we should believe that things are as they seem unless we have good evidence that they are not. If we can find no good reason to doubt that things are as they seem then we should accept it is probably so. Swinburne is not suggesting that we naively accept that the world is as it appears. A rational person critically examines the world; she does not assume that the world actually is as it appears, so she is open to evidence that things are not as they seem. In so doing, she moves from appearances to the truth. However, every inquiry has to start with some set of data, and has to assume some point of view.
If we cannot start our quest for truth by assuming that most of our ordinary beliefs - about the immediate past, our physical surroundings, the testimony of our neighbours - are probably true, we cannot start at all. Moreover, we cannot choose our beliefs at will, and we cannot force ourselves to believe that our most basic beliefs are false. With the principle of credulity, Swinburne is joining a philosophical tradition that goes back to Aristotle. Furthermore, science builds on this tradition. Scientists test theories by observation and measurement, and science is a communal project, each scientist relying on the findings of other researchers. The scientific enterprise collapses into a sceptical morass if we cannot believe what we observe and if we cannot trust what others tell us.
This book is important for apologists because in The Existence of God Swinburne argued that the existence of consciousness provides evidence for God’s existence. It seems to me that the discussion in Mind, Brain and Free Will certainly gives reason to prefer Theism to Physicalism. If physicalism is true, physics should have the potential to give us a complete description of reality. (The laws of genetics and natural selection will follow from the fundamental laws of physics and the initial state of our universe.) Physics describes a universe with ultimate and irreducible properties of things, like charge, mass, charge, motion and spin. These fundamental physical realities are governed by relatively simple mathematical laws.
But conscious states like "awareness" and "aboutness" are not the kinds of state that are described by physics. They arrive too late in the history of the universe to be fundamental; furthermore, it is impossible to see how they could be described mathematically. It is difficult enough to describe a specific feeling of "misery", " or "ecstasy" in poetry or painting. While the associated brain state can be measured in mathematical terms, the phenomenal feeling cannot. Physicalism cannot account for conscious states, whereas Theism, with its commitment to a personal creator, has no difficulty in explaining conscious experience. We think – therefore there is evidence that God is!
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