A critique of identity theoy

A relatively old essay I have written for my Philosophy of Mind class

A Critique of Identity Theory

Which part of the body is responsible for mental activities? The content of the word “responsible” might need some clarification but given the scientific and technological evidence, it is safe to say that brain states and mind states are related. For example we can manipulate some moods and feelings with certain drugs. Also we can observe that brain damage can lead to loss of some mental activities. For the other side of the correlation, that is the effect of mind on brain; we can use the fact that using FMRI, one can screen the changes in the brain of a body that is engaging in mental activity. A theory that is based on these observations is the Mind-Brain Correlation Thesis, which says that for each mental event M there is a brain state B such that, M occurs to the subject if and only if B occurs to the subject. [Kim, page 82] To explain it better, if there is a mental event, there should be a change in the brain and if the same kind of change in the brain occurs, the same mental event should occur. In other words, we can not expect mental events to happen without any change in the brain. These are called “psychoneural” correlations since they correlate mental (psychological) events to brain (neural) states.
Once we are convinced that there is a correlation, the second step will be asking if it is possible to find out the nature of it. At this point I want to introduce some theories from the literature of mind-brain correlations which attempt to explain this correlation or argue that such an explanation is impossible. I will give a brief summary of these. Descartes as a dualist does not deny the relationship between nervous system and mentality. He says that the immaterial being, which is the mind, interacts with physical body through the pineal gland. Similarly, the physical body interacts with mentality through the same organ. This is called “causal interactionism”.
Leibniz believes in the “pre-established harmony,” which says that mind and body are correlated because God had set our minds and bodies in a harmonious way and then started our beings. Another view which is close to this is the “occasionalism” which claims that at each moment there is an interaction between mind and body, God was there to do it. Another argument which might be more plausible compared to theories above, is the Double-Aspect theory by Spinoza which says that changes in mental and mind states might be results of a common cause rather than being caused by each other. Another theory is “epiphenomenalism” which says everything is a result of a physical status in the brain. It claims that although it seems like our will makes us do something which might be mental or physical, it is just a state of brain that causes the feeling of will. Therefore there is nothing mental that causes something physical. Another one of these mind-body correlation theories is the “emergentism” which mainly says not to try to understand the relationship between neural states and mind states, and accept it as a fact since mental phenomena can have no explanations as biological processes.
After this long but important introduction which shows the difficulty of bringing an explanation to the mind-brain correlations, we will focus on the Mind Body identity theory, which asserts more than the existence of the correlation, but as a pay off can not say enough about that correlation. This theory identifies the mental events and physical events that seemed to be correlated at the beginning of the discussion. Just as lightning is nothing but electrical discharge, mental events are nothing above or over the neural states of the brain. Simply they are two different namings of the same phenomenon, based on different perspectives or understandings of it. For example instead of saying that pain occurs if and only if C-fiber stimulation occurs, we now say: Pain is precisely C-fiber stimulation. Since the attempts to explain the mind-body correlations were very controversial, mind-body identity theory seems to have done a good job of solving the problem without bringing in new immaterial objects to make the connection between consciousness and neural states. That is because there is no need for a connector as they are already connected by being the same thing. The only problem is: has this theory really said enough to be convincing? I think we still need a defense from the identity theory telling us why we should believe that mind states are identical to brain states.
Here is support for the identity theory from J.J.C. Smart. In his paper “Sensation and Brain Processes,” he responds to disputes with arguments based on Occam’s simplicity principles. Occam says that:
i) Entities should not be multiplied beyond necessity.
ii) What can be done with fewer assumptions should not be done with more.
[Kim, page 89]
I will postpone the discussion of these principles to a later time and first show how identity theory does or does not work well with regards to Occam’s principles. Identification is a direct way of reducing the number of identities. However, we should be careful, since sometimes shrinking the set of identities might not be the inverse operation to multiplication of them. For instance if these two identities which are reduced to one thing are not the really the same things, what has been done is not reducing multiplied identities. If the entities that we collect under the same label and reduce to one thing are not the copies of same entity, then what we have done has nothing to do with Occam’s first principle, and moreover we will be losing information while eliminating some notions by wrong identifications. To be clear, reduced entities should be the same to be able to refer to the Occam’s first principle. Therefore to be able to refer to Occam’s first principle, Mind-Body Identity theory should prove that mind and brain are identical.
A second claimed advantage of the identity theory is that if it is a valid one, it will enable us to talk about mental states with a physical language. Therefore, physical facts and physical language alone will be enough to explain the nature of mind completely. This means that we will use fewer assumptions to understand the world. This seems to be consistent with Occam’s second principle. But first, the theory should prove its validity and after that if there are two valid theories we can favor identity theory since there is minimal number of assumptions and notions. But what is validness, how can two things be valid and say different things? If we are seeking for the “truth” rather then making sentences or constructions which are consistent in themselves, I would call something as valid only after it is proven to be true. Before proving validness (truth), I would be skeptical to favor one theory to the other. That is because we do not know enough the nature of the true information and form of it, to be able to pick the best theory that fits this nature.
The other justification of the theory is that: if we want to explain everything with the physical language, at some point pain should be a given physical interpretation since there is no totally physical word standing for pain and we can’t make a totally physical argument which correlates physical phenomena to pain. Therefore, at some step, one should identify pain with some physical phenomena or leave it as an unexplained fact. If we leave it unexplained rather than identify it with something physical, then there would be infinitely many correlations which can not be reduced to anything else and they will make the world extremely complex, according to Smart.
Since we have mentioned the highlights of the Smart’s paper, we can go into a deeper critique of his ideas and the mind-brain identity theory. First of all, as I promised let’s start with Occam’s razor. I completely agree with the principles but can also see how they might be misinterpreted and used in a wrong way. It is plausible that there is no need for multiplication of entities, since multiplication will not give us anything new. Moreover they might be confusing for those who do not know that these new entities are copies of some previously known concepts. However sometimes we might need to do this for practical purposes. There is nothing wrong with multiplying as long as a person keeps the multiplications made in mind, and at the end eliminates the duplicates. Under the circumstances mentioned, I would not call this operation multiplication of an identity. Having already explained that reduction of notions can be done as long as they are known to be the same things, there is not much left to say about Occam’s first principle and that Smart owes us an explanation about why they are identical. However, the second principle, which is quite plausible, might be misinterpreted by people as it has been by Smart. If you do not need a concept to explain a phenomenon then why to use it? However, it seems that one should make sure to know what “explaining” means. First of all we may feel like we have explained everything concisely with the identity theory, but did we? We just made an assumption which is very controversial and it simplified the problem a lot. Identifying mind and brain is not an explanation unless we know that it is true. Therefore, it is not intelligent to stick to a theory just because it is simple. Occam’s razor says to pick the simple explanation, but there are no explanations as we can not know which one is true or is any of these theories are explaining the real phenomenon that is occurring between brain and mind. Another point is the truth might not be that simple. Hence it might be going beyond our current scientific understanding. Occam’s razor is not saying that the truth should be simple. It just says that if something can be explained with fewer notions, one should do so. Hence, if there are two real explanations to a phenomenon (here real means, an explanation of the truth rather than a theory that stands for an explanation until it is disproven) they will be able to explain each other’s ideas and tools and help to further simplification with the insight gained from these two perspectives. What we have in the end will be two analogous explanations with the smallest number of notions. Therefore Occam’s second razor is really wise. If there are two real explanations they can be simplified in a way that at the end they are analogues and two analogues things will have the same number of notions, and this number will be less or equal to the minimum of the number of concepts of the two theories. However, we should repeat that a theory that stands for an explanation might not really be an explanation of the real phenomena and no matter how simple it is , since it is incomparable with other explanations it can not be favored to them. Unfortunately, Identity theory can not fulfill the assumptions of Occam’s razor and therefore Smart’s arguments fail to be valid and support Identity theory.
Rather than showing how simple the theory is, he should have given us some ideas to support the claim that mind is identical to brain. If identity theorists want to avoid the correlation question, it is fine, but then they should definitely say more about why they are identical, a much more difficult question. And since there is no rule that truth must be simple, they are not allowed to leave this problem just because it is hard to answer and might force them to introduce new, complicated notions.
References:
1) Kim, J. Philosophy of Mind,
2) Heil, J. Philosophy of Mind, a guide to anthology