Doctrine of Man (Part 9): Evaluation

Evaluation

1. Dualism-Interactionism:  the Mind/Body problem

In our last session we completed a look at the biblical data supporting a dualistic view of anthropology. Today I want to say something by way of a philosophical defense of dualism-interactionism. Rob Koons and George Bealer in their book The Waning of Materialism have pointed out that the physicalist view of the mind has been waning in recent years among professional philosophers. They're beginning to realize the many problems with a materialistic anthropology and are starting to move away from it. In order to appreciate the problems that materialism faces it will be helpful to draw some basic distinctions in the philosophy of mind.

There are two fundamentally different accounts of the mind. One will be physicalism (or monism), and the other will be dualism. Physicalism holds that there is no immaterial constituent of human being – that human beings are simply material organisms. Physicalism comes in two versions. One is reductive physicalism, and the other is non-reductive physicalism. Reductive physicalism holds that mental states are identical to physical brain states. So far as the mind is concerned, there is just the brain and its physical states. All of our supposed mental states are reducible to brain states. By contrast, non-reductive physicalism holds that while our mental states are not reducible to the brain or to physical brain states, nevertheless the mind or soul is not a real thing. Mental states are mental properties that supervene on the brain states and are ontologically dependent upon them.

We can distinguish two types of properties in this regard. On the one hand there are the physical base properties that are ontologically the ground of these higher supervenient mental properties. Once all the physical properties are in place, the claim is that the supervenient properties just automatically come along as part of the package. A good illustration of this sort of supervenience is the wetness of water. Water, as you know, is H₂O – just hydrogen and oxygen. But neither hydrogen nor oxygen is wet, right? So when hydrogen and oxygen are combined as H₂O the property of wetness supervenes on the hydrogen and the oxygen. The view of non-reductive physicalism is that all that really exists is the brain, but mental states or properties supervene on the material brain somewhat in the way that wetness supervenes on H₂O. Any causal powers of the water are not due to the supervenient properties. The causal powers are due to the underlying base properties of the oxygen and the hydrogen to cause and bring about certain things. Similarly, the causal properties of the brain are its physical properties, not its mental properties.

What might be said about these two forms of physicalism? Let me draw upon the work of a very fine philosopher of mind Angus Menuge and his paper, “Why Not Physicalism?”[1] Menuge lists several problems confronting a materialist or physicalist philosophy of mind. Menuge says,

Reductive or eliminative forms of physicalism fail to account for our mental lives. But . . . the varieties of non-reductive physicalism also fail to account for mental causation. If these [non-reductive] theories are faithful to physicalism, then supervening or emergent mental properties cannot add anything new that was not going to happen anyway, as a result of their physical base properties. If we want to account for consciousness, mental causation and reasoning, we need some entity over and above the body. This entity must be simple, have thoughts as inseparable parts, persist as a unity over time, and have active power. That sounds like a soul . . . .

Let's break this paragraph down a bit. Here Menuge distinguishes between two types of physicalism. First is reductive or eliminative physicalism. Reductive or eliminative versions of physicalism are increasingly unpopular. They just don't seem to account, as Menuge says, for our mental lives because the brain, as a physical substance, has only physical properties, such as a certain volume, a certain mass, a certain density, a certain location, a certain shape, and so on. But the brain on this view doesn't have any mental properties. The brain isn't jubilant or sad. The brain isn't in pain. Take the phenomenon of fear, for example. When you have fear, undoubtedly there is brain activity that is correlated with the experience of fear. The dualist-interactionist agrees with that. It's not as though the soul operates independently of the brain. Rather, there is an interaction with the brain in the experience of fear. But the brain itself isn't afraid. You can't reduce fear to a physical brain state even though it is correlated with neural activity in the brain. So reductive physicalism is obviously untenable. It cannot be reconciled with our mental experience.

This has led many thinkers to affirm some sort of non-reductive physicalism. The brain gives rise to supervenient states of awareness like jubilance or sadness or pain. But there isn't any thing – there isn't any soul or mind – that has these properties. Rather the brain is the only thing that really exists, and mental states are grounded in the brain. Menuge identifies a number of problems with this view.

First of all, he points out that it's incompatible with self-identity over time. Think about it. The brain endures from one moment of time to another; the brain thus has identity through time. But its states of awareness don't endure from one moment to the next. There is no enduring self – no “I” (capital-I) that endures from one moment to the next. This view of the self or the “I” is rather like the Buddhist view of the self. The Buddhist says that the self is something like the flame of a candle. The candle and the wick endure from one moment to the next, but the flame doesn't endure. There is a different flame at each moment of the candle’s burning. The flame exhibits a sort of continuity in that the candle doesn't go out while it's burning, but there isn't really any identity of the flame from one moment to another over time. The situation with the self is similar on non-reductive physicalism. Every state of the brain at different times has a different state of awareness associated with it, but there isn't any enduring self or “I” from one moment to the next. This leads a naturalistic philosopher like Alex Rosenberg to affirm the radical position that there is no enduring self on atheism. The existence of the self, he says, is an illusion. In his book The Atheist’s Guide to Reality, Rosenberg affirms, “I do not exist.” Similarly, it's an illusion that you are the same person who walked into class this morning. In fact, you are not the same person because there is no personal identity over time. If you do believe that you exist and that you are the same person who came into class this morning, then you ought to reject a non-reductive physicalist view of the self.

Secondly, intentional states of consciousness don't seem to make sense on non-reductive physicalism. The property of intentionality is the property of being about something or of something. For example, I can think about my summer vacation or of my wife. Physical objects don't have these sorts of intentional properties. The brain is not about something any more than a chair or this podium is about something or of something. It is only thoughts which are of something and so have aboutness or intentionality. But on non-reductive physicalism there is no self which has states of intentionality. So intentionality is, in effect, an illusion. Again, Rosenberg bites the bullet and says we never really think about anything. It's just an illusion that we have intentional states. He acknowledges that without intentionality sentences aren't about anything because a sentence is just a bunch of ink marks on a piece of paper and therefore not about anything. They are just meaningless marks. So he says that every sentence in his book is meaningless including that sentence! He asks, what good does a book like this do? Why even write it? His answer is that if looking at these ink marks on paper causes certain neural firings to take place in your brain such that your activity is altered, then the book will have achieved something. But, of course, that achievement can't be Rosenberg's purpose in writing the book because on his view no one has any purposes for anything. I think at best he could say that he was determined to write it, and you are determined to react to it in the way that you do. But it's difficult to see here any sort of overarching purpose or significance to it. In any case, the denial of intentional states is not only contrary to experience – I mean, after all, we are thinking about Rosenberg's argument, aren't we? – but is actually self-refuting. For what is an illusion? An illusion is always an illusion of something. So an illusion is itself an intentional state. An illusion of intentionality is an intentional state. You are having an illusion of something. The view that intentionality is merely an illusion is literally self-refuting and incoherent. So again, if you think that you ever have thoughts about anything or of something, then you ought to believe in the reality of the soul and to reject non-reductive physicalism.

Thirdly, free will seems impossible to reconcile with either reductive or non-reductive physicalism. On these views there is no causal connection between the sequential states of awareness. Mental states are not causally connected. The only causality is purely on the physical level, and that is completely determined by the laws of nature and the initial physical conditions. There just isn't any room for freedom of the will. So on this view, again, free will is an illusion. You never really do anything freely. And that flies in the face of our experience of ourselves as free agents. I can freely choose to think about certain things or to do certain things. I'm not simply determined by my brain states. So if you believe that you ever do anything freely, then you have good reason to believe in the reality of the soul and to reject these reductive and non-reductive views of physicalism.

Menuge also points out that if we want to provide an account of reasoning we need a soul. If there is no self who reasons from premises to conclusions, then we are just like a pocket calculator which is such that when you press the buttons 2, +, and 2 and then hit the equal sign button, the calculator reads 4. But the calculator doesn't reason to arrive at that conclusion. There's no reasoning going on there at all. It's just electronic circuitry firing. Again, if you think that you ever reason to arrive at a conclusion, then you ought to conclude that you are more than just a moist robot; that in fact you are a self who does this reasoning.

Finally, fourthly, the last phenomenon that Menuge points to is mental causation. Notice that on these non-reductive physicalist views, the only arrow of causation is from brain states to brain states (represented by B and the causal connection by the arrow) and from brain states to correlated mental states (represented by the letter M).

M   M   M   M    M

                 

BBBBB

The only causation that exists among these states is from brain state to brain state and from brain states to the correlated mental states. But the epiphenomenal mental states themselves don't cause anything. There are no causal connections between the mental states nor do they have a sort of reverse causation on the brain states. They are utterly causally impotent. So there is no return causality from states of awareness to the brain. Why? Because there is nothing there. There is no soul. There is no mind that can exert a causal influence on the brain. On this view the arrow of causality goes only in one direction – from the brain to these epiphenomenal states as well as from physical brain state to brain state. This is incompatible with my introspective grasp of my ability to cause things. I can cause my arm to go up. I can raise my arm by thinking about it. I can do other things through thinking and therefore bring about causal effects. Menuge also discusses what's called neuroplasticity, according to which thinking can actually affect the brain. If you think in certain ways, it produces brain effects. There is even a kind of cognitive therapy that in some cases is more useful than drugs in changing people's behavior. If you can alter the way that the patient thinks about something, this will affect the patient physiologically. It will actually bring about different brain states through thinking. This seems to me highly significant because in his book Rosenberg says that if you find all of this depressing (that there is no self, there is no identity over time, there is no intentionality, there is no free will) he says, well, there's always Prozac. He's serious! I mean, what else would a materialist say? He says, take drugs! If you take brain-altering drugs, then you'll feel better. Just how sinister that advice is, I think, is shown by Menuge’s point that we don't always need to resort to drugs. Sometimes there are cognitive therapies, where by changing your thinking you can actually alter the brain and get better.

In all of these ways it seems to me that Menuge is right – that we ought to reject these physicalist views in favor of some sort of dualism-interactionism; that is to say, we are composites of soul and body, and the soul and the body together (in particular, the brain) work together to think.