The mind is what the brain does?

I recently ran across this post by neurologist Dr. Steve Novella over at his blog Neurologica. The post is basically a rebuttal to neurosurgeon Michael Egnor’s views regarding how memory is encoded in the brain; however, my agenda here is not to comment on this exchange. Rather, this current post of mine was sparked by comments made by Dr. Novella in his post regarding the nature of the mind. Here’s some of what he had to say:

As I have pointed out numerous times myself – mental phenomena are functional active things. They are based in the physical substance of the brain, but they are not just the physical substance – they are what results from the function of the physical substance. The mind is what the brain does.

I’ve heard this theory of mind put forward many times; that is, the theory that the mind just is what the brain does. Note that this is not the same as saying that the mind is identical to the brain, rather it simply says that psychological states just are the products of neurophysiological processes. This theory is simply a type of identity theory. Identity theory is a type of reductive materialism and is defined, by the Stanford Encyclopedia of Philosophy, as the theory that “states and processes of the mind are identical to states and processes of the brain.” And this seems to be exactly what Dr. Novella’s position is, for he says that “mental phenomena (including memory) do not simply correlate with the firing of neurons in the brain – they are the firing of neurons in the brain.”

The first step that most materialists take towards justifying identity theory—or really any variation of a materialist philosophy of mind—is to provide evidence from neuroscience that demonstrates that the brain and mind are intimately related. And needless to say this evidence is not lacking at all. We know quite well that altering brain chemistry and brain structure can subsequently alter personality, can create a “divide” in consciousness, and can even cause individuals to fail to recognize familiar objects or even loved ones. There is no doubt that this says much about the correlation between the mind and the brain, but does is say any more than that by itself? Not really. Philosopher of mind James Madden, in his book Mind, Matter and Nature, articulates:

Has neuroscience revealed an empirical identity between psychological states and brain states? It clearly has not, nor does it seem that it ever could. What neuroscience does is to provide us with ever more precise descriptions of the goings-on in our brains that are correlated with our psychological states[…] Correlation is a far cry from identity; two phenomena can be perfectly correlated, without being identical. (p. 108)

The point then is that identity theory cannot be justified solely by the correlation between the mental and the neurological. As is commonly said, correlation does not imply causation. Now I maintain that not only can identity theory not be justified by pure findings from neuroscience, but I maintain that it is rife with ontological problems regarding actually accounting for how it is even possible that psychological states just are, and are reducible to, brain processes.

Intentionality and Necessary conditions

One of the first problems that identity theory runs into is accounting for intentionality. In philosophy of mind, intentionality refers to the ability of something to be about, or refer to, or represent something beyond itself. When I think of my wife, my thought is about, and refers to her. Now the problem here is that physical things only exhibit derived or secondary intentionality. The written word “cat” only refers to a cat if a mind so interprets it that way. It could just as easily have been the case that we endowed the word and utterance “cat” with a completely different meaning, or that another group of individuals takes the word or utterance “cat” to mean love. This means that physical symbols only have extrinsic intentionality and derive their intentionality from a mind that already exists. Now note that psychological states that exhibit intentionality do not borrow this intentionality from somewhere else. That is to say, our thoughts are not intentional because something external to us interprets them, rather they exhibit intrinsic intentionality, and thus our mental states constitute intentionality that is completely opposite the physical.

Now this posits problems for any philosophy of mind that is primarily materialistic. For how can a physical process be that which grounds intentionality if the physical first needs a mind in order to have intentionality at all? The materialist, then, needs a mind in the first place before he can start talking of intentionality being present in the physical. But the mind is the very thing the materialist is attempting to account for!

Furthermore, things get even worse for the identity theorist than this. Let us imagine a scenario where I raise my arm to a certain trajectory T1. Now let us say that I intended to raise my arm for some specific reason—perhaps to greet a co-worker. Now an identity theorist would say that my act of raising my arm can be accounted for in specifically neurophysiological events which terminated in certain muscular events which caused the raising of my arm. We can call this physical sequence that leads to the raising of my arm X1. Note that X1, by itself, is a sufficient condition for the raising of my arm to trajectory T1. So, the raising of my arm is therefore accounted for in completely materialist terms right? Not necessarily. For now imagine that instead of the physical sequence X1 causing T1, we say that this physical sequence is altered by only one neuron to cause a slightly different trajectory in my arm raising. So we can call this different physical sequence X2, and this new trajectory T2. So now we can say that X2 is a sufficient condition for the raising of my arm to trajectory T2.

But this is where we run into problems. While X1 might be sufficient for raising my arm to T1, and X2 is sufficient for raising my arm to T2, X1 and X2 are not necessary conditions for raising my arm as an intentional act. That is, in order to raise my arm as an intentional act, I do not need X1 or X2, but could have some other physical sequence obtain. But this means that no specific physical act is necessary for explaining the intentional act of raising my arm! Rather, while physical processes are sufficient for explaining my arm being raised in a certain specific manner, they are not sufficient for explaining my arm raising as an intentional act. Now note that if psychological states just are neurophysiological processes (i.e. if the mind is what the brain does), then certain physical sequences would be sufficient and necessary conditions for raising my arm intentionally. And since this is not the case then it cannot be true that our psychological states just are processes in the brain.

Rationality

A second problem that confronts identity theory is that of rationality. When certain neurophysiological states in the brain are followed by other subsequent neurophysiological states, neurologists understand exactly how these states follow from one another. If S1 (a neurophysiological process) is followed by S2, which is then followed by S3, it is the electrochemical properties of the brain, ultimately grounded in physical laws, that cause this transition. Now imagine that I entertain the following line of thought: 1) John is usually late to class on Mondays, 2) It’s Monday, 3) Therefore, John will most likely be late to class. Now notice that, on identity theory, each thought (each psychological state) will correspond to a certain brain state (neurophysiological process). But this means that if identity theory is true, then the cause of me inferring 3) from 1) and 2) is simply the electrochemical properties associated with those brain states.

This obviously runs into problems. For my act of inferring 3) was due to the semantics associated with 1) and 2), and I simply saw logically that 3) follows. And, in fact, for any inference or conclusion to be considered rational, it needs to be caused by the meaning and semantics of previous thoughts, or propositions. But, again, this is not true on identity theory. On identity theory it is not the semantics of 1) and 2) that cause the mental state of 3), rather what causes 3) is simply the blind electrochemical properties of the neurophysiological state associated with 2), which was caused in the same way by 1). But this type of causation is purely blind deterministic efficient causation. That is, it is simply matter dancing to the tune of physical laws, and therefore cannot be called rational in any sense. Thus stated, on identity theory any type of “rational inference” is, upon closer inspection, only pseudo-rationality, and therefore rationality as such is only an illusion.

Note that these are not the only devastating critiques of identity theory (there are others that I've put forth here and here). But I believe they go a long way in demonstrating that this reductive materialist theory of mind—that the mind is what the brain does—is vacuous. Now let it also be noted that the arguments above are not soul-of-the-gaps arguments. That is, the arguments are not saying “this or that aspect of cognition is difficult to explain currently, so we need to posit the soul or some Cartesian substance to account for them.” Rather the above arguments are ontological and deductive. That is, they don’t argue from current scientific ignorance, but instead argue that the ontology of a materialist theory of mind cannot ever in principle solve these problems. These problems then are a sort of reductio ad absurdum of materialism, and thus findings in neuroscience are irrelevant here.

In conclusion, then, we see that identity theory rests on a conflation of correlation with causation, and faces insurmountable arguments that demonstrate that the mind cannot simply be “what the mind does.”

Semantics and the mind

Last week I posted an article devoted to articulating the famous Argument from Reason (AfR). This argument attempts (and succeeds, in my opinion) to demonstrate that if naturalism were true, then there would be no such thing as reason. The AfR goes about demonstrating this by first highlighting the nature of reasoning. Reasoning, according to David Bentley Hart, is “to proceed from one premise or proposition or concept to another, in order ideally to arrive at some conclusion, and in a coherent sequence whose connections are determined by the semantic content of each of the steps taken”. The AfR then contrasts this account of reasoning with “reasoning” on a naturalistic worldview. See, for the naturalist all that exists are material processes governed by the laws of physics. But, this means that the cause of “reasoning,” on naturalism, is not semantics and meaning, but only electrochemical properties in the brain—there’s more subtlety to the argument than this, this is simply a quick summarization. Thus, it is argued, there would be no such thing as reason on a naturalistic worldview.

After articulating this argument on the aforementioned post, a frequent and attentive commenter named Ray posted some of his objections in the comment section. One of these objections I found to be quite substantive, and thus I felt the need to write a post addressing it.

His objection was that the AfR makes a hidden assumption that needs to be supported. The AfR contrasts semantics and meaning (the basis of reasoning) with purely material processes, and it claims that the former constitutes reasoning and the latter does not. However, the naturalist believes that semantics and meaning themselves are also the result of purely material processes, and therefore the proponent of AfR is creating a false dichotomy. He makes it seem as if the naturalist must choose between a rational cause—grounded in meaning and semantics—or a non-rational one—both choices leading to a rejection of naturalism. However, if meaning and semantics are themselves the result of material processes then there is no such choice for the naturalist—that is, there is no choice between a process grounded in non-material causes and material causes, since on naturalism all causes are ultimately material in nature. Thus stated, the proponent of AfR needs to demonstrate that semantics and meaning are not reducible to material causes before the AfR can be valid.

I do believe that this is a good and valid objection to the AfR. So let us see if semantics can indeed be reduced to the material. Let’s begin with an example. Take the symbol “2”. What does it stand for? Well, it stands for the concept of “two”, derived from set theory to represent the set containing two elements (II). But, it’s important to point out that the symbol “2” does not contain this meaning intrinsically. If that were true, then the symbol “2” would necessarily have to have represented the concept “two”. But the symbol “2” is completely arbitrary. In fact, it’s quite possible that we humans could have designated “2” to represent the number “five” instead, or it could have represented the concept of “love,” as opposed to a heart, if we so chose to embed it with that meaning.

Another way to demonstrate this is by imagining a primitive tribe that actually does take the symbol “2” to mean “love”. Now, if this were a true state of affairs then we could ask the question, “What does ‘2’ mean?” And the answer would be that it depends. To us it means “two” and to the tribe it means “love”. All this means that the symbol “2” by itself is intrinsically nothing but a meaningless squiggle. Its meaning is only grounded in minds who impart meaning to it. And what’s crucial here is that we can say the same regarding any symbol.

Hence, symbols can only exhibit derived meaning, and thus their semantic value is of a secondary, and borrowed order. But, symbols are the only type of meaning that we’ve seen material things exhibit, and therefore our conclusions regarding the secondary semantic nature of symbols applies to the physical as well. Thus stated, we arrive at the following conclusions regarding the physical. First, the physical and material can only gain meaning from a mind. (This of course demonstrates that naturalism cannot account for the semantic content of the mental, because meaning already presupposes the mental, and it cannot therefore account for it without arguing in a circle.) Second, meaning is not intrinsic to the physical, but is only derived, or borrowed.

I maintain that all this suffices to show that the skeptic’s challenge has been met. It has been demonstrated that semantics and meaning cannot be reduced to the material. Therefore, since semantics cannot be reduced to the material, then the contrast between rational and non-rational causes that the AfR promulgates is valid. Thus stated, the AfR stands and refutes naturalism.

Moreover, even if the above demonstrations didn’t lend validation to the AfR, they would still land a fatal blow to any naturalist theory of mind. For, to reiterate, if the phenomena of the mental cannot be reduced to the material, then naturalism is in jeopardy. And I maintain that we have done just such a thing by demonstrating that semantics cannot be found in the material, but must be predicated of the mental alone. 

The argument from reason

Let us examine the following familiar syllogism: 1) All men are mortal, 2) Socrates is a man, 3) Therefore, Socrates is mortal. This syllogism is logically sound, and it can be reasonably seen why the conclusion follows from the premises. But, how exactly is it the case that we reasonably deduce the conclusion? Well, it’s the case because we understand the semantics behind every proposition in the syllogism. That is, we clearly comprehend what 1) and 2) mean, and we logically deduce the third proposition (the conclusion) based on the meaning of the preceding premises. This is the process of reasoning, namely, making deductions based on the semantic content of previous concepts, propositions or ideas. Thus stated, our deduction from 1) and 2) to 3) is based on meaning, semantics, and reason.

Now what is going on psychologically when we make our way, logically, through this line of reasoning? Well, we have a brain state and a mental state associated with upholding premise 1), and the same with regards to 2) and 3). The brain state is just what is happening electrochemically in my brain when I uphold a certain proposition or thought, and the mental state is the associated with the actual mental apprehension of said proposition or thought. (Note: even if one is an eliminative materialist and therefore doesn’t believe mental states exist, the distinction between brain and mental states is not crucial to my present argument, and would actually make the force of the argument stronger.) It should be obvious that brain states and mental states are different with regards to the different propositions we are upholding. That is to say, the brain state and mental state we have for 1), will be different from the brain and mental state we have for 2), and 3).

However, one immediately encounters a problem with the above promulgations if one is a naturalist. Why? Well, remember that a naturalist believes that all that exists is mindless matter, or energy, governed by the laws of physics. A corollary of this is that any thoughts (and, therefore, any mental states) are ultimately the result of physical processes swinging to the tune of physics. But, this means that the mental states associated with upholding 1), 2) and 3) are ultimately grounded in, and caused by, the electrochemical properties of brain states.  A consequence of this is that when the brain state associated with 3) succeeds 2), which succeeds 1), this succession was the result of only physical laws acting on the matter that makes up these brain states.

But, this completely conflicts with what we expounded above, namely, that is it the meaning and semantics associated with our syllogism that causes us to arrive at such a deduction. On the naturalistic account of the world, when one makes their way down the syllogism, it is not the meaning or semantics that leads one there, but, rather, purely  mindless electrochemical processes. But this means that, on naturalism, it is not reason-- making deductions based on the semantic content of previous concepts, propositions or ideas—that grounds our thinking. In fact, based on what we’ve discovered, there is no room for such a thing as reason on naturalism!

The naturalist position, then, results in a reductio ad absurdum. That is, if naturalism were true, then we could not reason, which means we could not arrive at the conclusion of naturalism, since to do so would require reasoning deductively. Naturalism, therefore, cannot possibly be true.