Neural States and Rationality: Can A Materialist Think?

Paul asked a good question in a comment yesterday:

"Why can't a materialistic view incorporate a hypothesis that one way in which neurons will cause other neurons to fire, initiating even the behavior of coming to a rational conclusion, is by one set of neurons that represent "Socrates is a man" and one that represents "All men are mortal" both combine to fire a set of neurons that cause someone to say "Socrates is moral." (I'm simplifying the organization of neurons in the brain, but I hope you get what I mean)."

The simplification of description is fine here; the question and the answer come out the same regardless of the level of complexity. And in answer to the question in my title here, of course materialists can think! But can they coherently explain how they can think?

Paul has very succinctly raised a form of the "mind-body" problem, which has vexed philosophers for years. There are a number of ways to address this, of which I'll set forth just a few, quite briefly.

Let's work backwards from the final neural state Paul mentions, "Socrates is mortal." This, he suggests, has been caused by the preceding neural states, "Socrates is a man," and "all men are mortal." By Paul's statement of the problem, there are no other causes; the two preceding neural causes are sufficient to produce the neural state, "Socrates is mortal."

This leads in some fascinating and troubling directions. For one, though the two prior neural states are sufficient causes of the final one, we do not know if they are necessary conditions. That is, could the final state come about through other causes instead? Could it have come about through previous neural states corresponding to, "Socrates is a fictional figure," and "All fictional figures are mortal"? Or, "Socrates is man," and "All men are mortal, even though women are immortal"?

Clearly those sets of beliefs are erroneous. But what if I said, both of those neural states are erroneous? What could it mean for a physical state to be erroneous? How could a chemical reaction be "wrong"? Or, how could an electron go the wrong direction? Under a purely materialist viewpoint, physical systems just do what physical systems do, following their natural regularities (laws) or quantum indeterminacies. Can a natural law go wrong? Worse yet, can a chance quantum effect be described as a mistake? Certainly not.

By this view, no belief could fairly be described as mistaken, because all beliefs are just the product of natural causes, to which the terms "error" and "mistake" cannot apply. And consequently, neither could any belief be described as correct. Not even the belief that "successive neural states explain human thought" could be described as right or wrong. It cannot be correct. It cannot be incorrect. It can't mean much of anything. This applies to all belief, by the way, so it would also be impossible to assess a belief like, "Hitler was correct in attempting to exterminate the Jews, and I should pick up where he left off" as wrong.

A second issue with the materialist view of mind is that stated by C.S. Lewis: if the neural state "Socrates is mortal" is produced just by prior physical conditions in the brain, there is nothing to suggest those conditions should be limited to other neural states corresponding to other beliefs. The state corresponding to "Socrates is mortal" could presumably also come about through other physical causes. Indeed, we speak of physical causes affecting beliefs all the time: "He thinks she's wonderful, but it's just his hormones." "My daughter thinks I'm being a terrible mother, but really, she hasn't been getting enough sleep lately." "He believes there's a ghost in the room with him; it's a hallucination from the pain medicine."

In all of these examples, credibility is seriously undermined by being able to ascribe the beliefs to physical causes. As Victor Reppert said,

I think that the physicalists, in using reason, presuppose it to be what common sense suggests that it is, and that requires that their thoughts be about something, that they be causally efficacious in virtue of their content, that it is possible to perceive logical relationships, and that the obtaining of those logical relationships has something to do with what beliefs they hold.

The key phrase there is that common sense suggests that thoughts are "causally efficacious in terms of their content." We are much more confident of a belief that is clearly independent of physical causes. We believe it is the (immaterial) logical force of the Socrates syllogism--its propositional content--that causes us to move to its conclusion. A material view of the matter contradicts that and strips us of the right to that belief.

In other words, we value beliefs that flow from reasons with good logic, and where physical causes can be ascribed instead, we assume that logic is undermined and the resulting belief is therefore less credible. If all belief is the result of just physical causes, then how is it that all beliefs are not therefore completely undermined?

(Victor Reppert has written more extensively on Lewis's "Argument from Reason"--an argument that goes considerably further than I have just stated--including this additional online article.)

Finally, I suggest that a purely material view of the brain applies not just to beliefs but also to decisions. What causes our decisions? If it is only material forces--natural regularities and chance quantum effects--it is hard to see how our decisions are our own, or are in any meaningful sense free choices.

Having said this about a materialist view of the mind-body problem, it behooves me to suggest a theistic solution to the dilemma. I do not pretend to be able to do that at all thoroughly here. I suggest, however, that a theistic view presents personality, mind, and will as more foundational to the universe than matter and energy. In the beginning there was God; matter and energy came later. (I speak informally of the time relationship here, please forgive me.) God created the universe, culminating in a creature made in his image; also, like him, possessing personality, mind and will.

That there is mind existing to some extent independently of mere material causes seems the essential conclusion of the problems stated above. Christians often describe a "substance dualism," meaning substance not necessarily as a physical thing but as "a kind of basic entity" or "something that stands under or grounds things." The mind and brain are distinct substances in that sense; the brain being the (relatively) familiar physical substance, and the mind being a non-physical substance. The mind, I suggest, is far more familiar to us than the brain. Some of the ancients believed the purpose of the brain was to warm the blood: they had no clue what it was really all about, yet they knew their minds. I've never looked at a human brain, thank you very much, but I'm pretty much at home in my thinking, my mind. The only problem we have with the mind in this relation is trying to describe it in language that is ill-suited for non-physical entities.

Clearly the mind and brain substances interact; we know mental states can produce changes in brain states and vice-versa. The independence of the two, while essential to any real view of rationality, does not have to be, and in fact is not, total. If we try to understand how they interact, we will not find a physical answer to the question. We will not find photons or gravitons or "thoughtons" being exchanged from one to the other. Such attempted explanations are in the wrong category, since the mind by definition is not a physical substance; and thus the mind-brain connection is not going to be the stuff of science. (If you insist that all explanations be scientific this will discomfort you; yet I suggest that discomfort must be less than the discomfort of having to conclude there is no such thing as right or wrong in rational thought.)

That personality, mind, and will are at the basis of all reality suggests that it is reasonable to believe there is a way, at the deep basis of reality beyond our scientific reach, that they interact. Frankly, I have to admit that beyond that it's a mystery to me also.

(If you're interested, John DePoe has another outline of the Argument from Reason, listing and briefly describing other lines it can follow.)

Part 1 in a Series
Part 2: Non-Material Vs. Material Mind
Part 3: We Know . . .
Part 4: Mind and the Material World

Posted: Tue - March 7, 2006 at 12:43 PM |

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Neural States and Rationality: Can A Materialist Think?

Thinking Christian by Tom Gilson