Eliminative Materialism

I have been thinking about this topic for indeed a long long time. (i.e. more than 3 weeks.) To summarise everything, here's the the essay that i wrote for my phil class. my professor Paul Churchland, together with his wife Patricia Churchland are among the top brains working on philosopy of mind, and active advocates of the shocking theory of Eliminative Materialism.
anyways, here's the thing...(i know. it's like a hundred pages...)

We talk about what goes on in our mind all the time. “I feel hungry.” “I love apples.” “I believe I should do this essay.” We are so used to this way of talking about our inner life that we cannot imagine living without it. Therefore, eliminative materialism naturally came as a shock. The eliminative materialist claims that common-sense psychology, or folk psychology, which is the way we talk about all mental states, is false, and the mental states talked about are non-existent. In the place of folk psychology, neuroscience will offer us better alternative understanding of the human mind, and eventually we will adapt to talk about mental phenomena in accurate biological vocabulary.

Before we analyze the theory of eliminative materialism, we shall first look at the theories of mind currently available and their limitations.

Opposing all materialistic views as a group, we have dualism, in which mind is believed to be a separate entity. Substance dualism, which states that mind is made of a different substance, cannot get rid of the problem of how the non-physical mind causally interacts with the physical body. Its inconsistency with the physical causal closure thus keeps the argument from being convincing. Popular dualists, who claim that mind is a different form of energy, like substance dualists, still owe us evidence that shows mind’s capability to exist without the brain, since the mind and the brain are distinct substances. Epiphenomenalists, although avoid the burden of showing that mind can exist without the brain because they believe the former is dependent on the latter, risk the danger of rendering any physical system, like a rock, as having mental states. All forms of dualistic views argue from introspection that they can only conceive mental states as being distinct from the physical things, but introspection might be as in accurate as our external sensations. Just like we cannot see the true identity of light as being electromagnetic waves because our eyes do not detect any other electromagnetic waves, our introspection might be just as limited and inaccurate in revealing the essence of our mental events. Moreover, when we use introspection to prove the existence of mental states, or to try to characterize it in any sense, we are actually using a mental process – introspection – to prove the existence of mental states. As the premise depends on the conclusion, this enters a circular argument.

Behaviourism defines mental states as what determines the behaviour or potential behaviour of the subject. By not directly addressing the nature of mental states gets away with many problems that dualists run into, but it cannot solve the problem of infinite combinations of behaviour, which makes definition of mental states difficult. And it still does not explain what mind is essentially and leaves a lot to be questioned

While the dualists and behaviourists failed to counter their difficulties or give any positive account to characterize the mind, materialists have learnt much from advances of sciences. The materialists believe in the existence of the physical brain, and the neural dependency of the mind on the brain. An identitist is firmly convicted that a physical system is necessary and sufficient to explain our mental life, and aims to match our mental states and brain states in a one-to-one fashion.

Development in neuroscience provides a platform for the identitists to make the connection between physical states of the brain and mental states (as we commonly understand them). As mentioned before, damage to brain parts leads to reproducible and specific loss of function in mental aspects of the patients. This pinpoints to a possibility that the identitists are right. The identitists believe that the sensation of pain is neither a non-physical substance nor some epiphenomena of the brain, but the event of firing C-fibre itself. Overall, the identitists suggest a scientific reduction of complex theories of mental states to simpler theories of brain states. There are many historical parallel, such as temperature being reduced to the average kinetic energy of molecules and lightening being reduced to electrical charges in the atmosphere. When two objects turn out to be the same, one is identified with and reduced to the other. In some cases, identity theory seems to work pretty well because some correspondence between mental states and brain states does seem to exist, with our current understanding of neuroscience. Seeing light seems to be identical to the event of rhodopsin being activated and leading to a series of subsequent biochemical pathways. Tasting sweetness seems to be taste receptors in the tongue stimulated to activate downstream pathway that leads to firing of a certain group of neurons.

One standard objection to identity theory, which is also an objection to all materialist point of views, is the argument from introspection. I do not perceive biochemical pathways when I introspect, but I perceive the sensation that identitists claim to equate the pathways to. I can see light but I have no awareness whatsoever of the function of rhodopsin. Identitists are seen to have not taken into account the experienced nature of mental events. This objection, however, does not stand, because of the fallibility of introspection as I have explained before in the section on dualism. There is anther objection, though, that the identity theory cannot avoid. Not all organisms achieve a certain mental state, for example pain, by the same mechanism, for example C-fibre firing. C-fibre firing is the process that results in only “pain” in human. In a worm, it is reasonable to suggest the presence of a percept analogous to the human “pain” but that is caused by firing of another fibre. In this case, it becomes unclear what pain is identical to. Therefore, a one-to-one reduction does not seem to work in all cases.

In order to solve the problem with matching that identitists encounter, functionalists suggest that what defines a mental state is its relationship with external environment, behaviours and other mental states. Putting mental concepts back into the abstract realm, the functionalists do not have to show that physical brain has any correspondence with the mind. Therefore they believe that the advances in neuroscience will not tell us much about mind. Objections to functionalism include the Inverted Qualia (person with inverted colour sensation but functionally normal) and Absent Qualia (China Brain). If mental states are only determined by functions, person with inverted colour sensation should have normal mental states, but clearly he possesses totally different mental experiences. Similarly, it is hard to conceive the population of China having any macro mental states although as a whole it is logically functional like a group of neurons or computer hardware. In response to such objections, the functionalists have to address the identitist point that there is something in the physical brain that corresponds and determines mental states, hence contradicting their purely functional definition of mental states.

Identitists and functionalists go through much struggle with matching the mental states as we usually understand them and what actually happens in the brain. Such efforts also penetrate the dualist views in order to explain what interactions actually go on between the mind and the brain. Mismatch of the mental states and brain states, often poses challenges to the aforementioned theories. Since the physical presence of the brain cannot be denied, it is tempting for a materialist, to reject all of the above theories and declare the mental states that we have been trying to explain empty and false. Elimination of mental states dissolves such difficulties.

Folk Psychology, or common sense psychology, is a theory that has been postulated by humans to explain others’ behaviour by simulating similar events in themselves, and then used to predict and eventually manipulate others’ actions. Our daily talks about beliefs, desires and emotions are all within the range of folk psychology. The formation of folk psychology is similar to that of other folk sciences in that the postulation of such theories is distinct from the strictly logical methodologies used in modern scientific generalizations. Like ancient mythology, the folk sciences and theories seem to be mere speculations about overtly complex phenomena that are beyond the means of investigation in that particular time, which definitely lack accuracy and credibility.

The eliminative materialist argues that folk psychology is partially or fully mistaken. Since the mental states that we understand and talk about are completely in the folk psychological sense, they might very well not exist at all once folk psychology is false, hence leaving only brain states that exist in reality. The eliminative materialists hence carries the discussion further by suggesting that since there are only brain states in reality, thorough studies in modern neuroscience will be necessary and sufficient to understand our mental phenomena.

The suspicion that folk psychology is falsifiable can be argued from two angles. Firstly, folk psychology does not represent our mental states fully, or even correctly, especially when compared with modern tools of neuroscience that can potentially offer us much more complete understanding of the nature of human mind. For example, nowhere in folk psychology are phenomena such as consciousness explained, nor do we learn anything about learning and memory from folk psychology. Theoretical and experimental neuroscience sets out to find the neuronal correlates of consciousness, learning and memory, and have already yielded promising results for some of the mechanisms involved in such mental activities. More often than not, folk psychology gives a wrong explanation for phenomena too complex for understanding. For example, folk psychology offers demon or witchcraft as an explanation for psychotic behaviours and hallucination in schizophrenia, which has already been determined by modern neuroscience to be a mental illness caused by nothing more than abnormal levels of the neurotransmitter dopamine. While folk psychology does not offer treatment because of poor understanding of the cause, modern neuroscience has succeeded in attenuating the symptoms of schizophrenia by externally administering drugs to adjust dopamine level. In any case, as a theory, folk psychology seems stagnant in its progress of understanding the mind problem, seems wrong when it does give an explanation and fails to predict mental phenomena accurately. This leads us to suspect the occasions when we think folk psychology is right. It is possible that we are so used to the system of thinking that we do not realize many other wrongs of folk psychology.

Secondly, folk psychology encompasses a system of representation of mental states in the form of propositional attitudes. Propositional attitudes are statements like “I believe P”, which has a syntactic characteristic. In other words, according to folk psychology when we express, understand or even just think about our own or others’ mental states, we think in terms of sentence-like structures. This is begging the question of whether we really do that. It is hard to conceive that infants, for example, when they first start interacting with the social environment before they learn the language, do not have any thoughts. Similarly, patients with mental illness that leads to a loss of linguistic functions also clearly lead a life with perfectly normally functioning sensations, emotions and desires. We have also experienced the situations in which we cannot describe in words the sensations or thoughts that we perceive. If we really sense, feel and think in a syntactic structure, this is not likely to happen. Therefore, language-like structure does not appear necessary for formation of thoughts in the brain, and folk psychology which bases its theory on syntactic structure of mental states seems wrong. On the other hand, if we abandon this theory of folk psychology and start to examine our so-called mental states on the ground of basic biochemical interactions in the physical brain, we might be able to find some other theories, more accurate and fundamental ones, that can explain how we simulate thoughts and sensations at all.

From the general narrative of scientific history, we observe a trend of folk sciences being eliminated. Folk physics used to prevail as a tool for human understanding and prediction of the natural world, but its mistakes slowly revealed as more scientific and modern physics theories developed. For example, the mistaken calorie theory was replaced by the correct theories of thermophysics. Such replacement has to be distinguished from a change of theory of light to the theory of electromagnetic waves. The former is an elimination process, and the latter is a reduction. Light can be reduced, or identified with electromagnetic waves because the two are essentially referring to the same thing, only that the second one is a more fundamental mechanism than the first. Here reduction is possible. In the case of calorie theory, a scientific reduction is not possible because the theory of calorie is fundamentally wrong, i.e. a substance such as caloric fluid does not exist in reality at all. Thus the concept of calorie has to be eliminated. Similarly, since folk psychology has been wrong in many cases, there is a very good chance that our so-called mental states do not exist and are irreducible to the objectively existing physical states of the brain, but has to be eliminated all together.

The eliminative materialist point of view is radical. It is definitely not easy to think that what we have been talking about for millennia, such as “I love Peter” or “I feel hungry” turns out to be false. If the eliminative materialists are right, then a new set of language has to be adopted for us to talk about our brain states (since mental states are no longer viable). This has happened before in history, however. The once prevalent phlogiston theory of fire is rarely discussed now because it has been proven wrong, and gradually people learn to drop the word “phlogiston” from their daily vocabulary. This illustrates that our language and ways of talking about things evolve as our understanding of the external world develops. The same goes for knowledge about ourselves. The elimination of folk psychology can be a long process, because it concerns ourselves and folk psychology has been around for as long as we can remember. As long as it is proven wrong, however, it is the logical and necessary thing to do to eliminate folk psychology eventually.

Some might complain that this theory dose not actually offer any explanation as to how mind works. On the contrary, I prefer this theory precisely because of its open-endedness. Firstly it has shed the burden of trying to explain the discrepancies between mental states and brain states by invalidating the former. Secondly as he eliminates folk psychology as a theory of the mind, eliminative materialist turns to modern neuroscience for alternative theories of how brain gives rise to mental events (not in the common sense of folk psychology). As our understanding of neuroscience is still rudimentary at this stage, it is not surprising that there are not thorough and satisfactory theories being offered. However, the elimination of common-sense mental states is an important step to opening our eyes to an array of new theories that might potentially be right. These theories will be formed and tested by tools of modern neuroscience, by scientific experimentation and logical deduction and are bound to be more complete, accurate and specific than the arbitrary and out-dated folk psychology.

One other objection states that if folk psychology as a theory and thus beliefs should be eliminated, then how can eliminative materialists themselves have a belief at all. To this objection, the Churchlands responded by saying that the eliminative materialist uses a belief to argue his case for elimination because he has no choice but to think in the context of folk psychology. This does not mean that folk psychology is therefore true, but only shows that there are no other conceptual frameworks available for the time being. (P.S. Churchland 1986).

The eliminative materialist suggests that when deemed not right, a theory is eliminated and a better theory is put in place of the first one. We cannot, however, be sure that the second theory is necessarily true, because there is indeed a possibility of an even better theory replacing the second one. As such, some worry that this suggests that all scientific theories are either false or potentially false and there will be no truth. I cannot say that this is not what happens, but I think that we can just do with the best theory we have, as long as it serves our purpose in its time. Folk psychology however, has proved to be wrong in many cases, thus the replacement of folk psychology with new theories from neuroscience is inevitable.

In conclusion, what eliminative materialists suggest might be true and just like the elimination of phlogiston, folk psychology will be replaced by a more sophisticated and accurate system of representation of our brain states, which is necessarily to be devised by advances in modern neuroscience.