Are mental properties identical to physical properties?

Last night after doing some preparatory reading for this essay, I went to bed. As I began to drift off, my mind remained on the subject of brain states, mental states, emergent properties and category errors. As my sleep deepened, I gradually became less aware that I was laying in bed thinking. The world familiar to me whilst awake disappeared and due, no doubt, to tiredness and my own inability to think clearly when tired, I completely failed to notice that the waking world had been replaced by a new very slightly different world. This dream world, although I was unaware of it as such, was entirely the product of my own mental states.

Still dwelling on matters dualistic I found myself in a position to conduct some research into the relationship between my brain and my thoughts. Working alongside some of the most brilliant minds (or perhaps ‘brains’) in the business it was decided that we should utilize MRI scanners, EEG’s and other tools to generate the most detailed images possible of my brain states at various points in time and in response to various stimuli. Very quickly, we were able to observe correlations between my state of mind and the corresponding brain states. Different parts of my brain would light up relating to different mental states. The more data we gathered, the clearer our understanding of correlations became. Eventually we developed such a detailed understanding of the relationship between what I was thinking and what my brain was doing, that we were able to conclude that all of my mental states were reducible to statements about brain states. This achievement would have been much more rewarding if we had not spent the whole time scanning the wrong brain.

We had never been able to prove which way around the causal relationship between brain and mind was operating and so, because the world around us appeared to exist objectively whereas my thoughts were merely subjective, we decided to assume that the brain was causing the thoughts. The problem was that in the dream, my real brain was nowhere to be found. It was in my head, which was resting on my pillow in my bed. We were busy at the imaginary lab working with an entirely imaginary brain that was entirely the result of my mental states. The changes in that brain were caused by changes in my thoughts; not, as we had assumed, the other way round.

Of course, the argument from dreams is not a new one. It has been raised before. My concern in raising it, is not one of radical skepticism so much as this; if my mind, or brain is capable of creating such a vivid private world that in no way, can hope to be expressed in its entirety through public behavior, such as language and so on, is Behaviorism justified to make the reduction that it does?

Within the context of such a dream, it would be perfectly reasonable to say that physical properties were identical to mental properties; properties of the physical world that I perceived were the contents of my thoughts. This is a very different claim than that which Behaviorists seek to make in claiming that mental properties are identical to physical properties.

Descartes’ substance dualism draws an ontological distinction between the mental and the physical, arguing that they are entirely different substances. He bases his argument primarily on what he perceives as differences between mental and physical properties. As he says in the sixth meditation:

“But nevertheless, on the one hand I have a clear and distinct idea of myself, insofar as I am simply a thinking, non-extended thing; and on the other hand I have a distinct idea of a body, insofar as this is simply a non-thinking, extended thing. And accordingly, it is certain that I am really distinct from my body and can exist without it.” (Chalmers, 2002, p.16)

Descartes therefore, commits himself to an ontological separation of body and mind claiming that mind can exist without body. In the context of my dream it is quite plausible to argue that my mind can exist without my (dream) body; however it does not follow from that, that my dream body could exist without my mind; unfortunately for Descartes, outside of the dream situation it is difficult to argue that our thoughts can exist without our bodies. The analogy of a dream, or the ability to conceive of oneself without a body, (whilst fortunate enough to experience the benefits of having such a body, and brain) does nothing to deter the materialist from claiming that all of the appearances to my dreaming mind were simply the result of physical processes; namely those occurring in a brain. A brain, which, at the time I was dreaming, existed outside of the realm of my experience.

This raises a basic epistemological problem for the materialist; how can we ever know, with any certainty that we are looking at the right brain? It is fair to say that the reasoning applied by my fellow researchers and I (in the dream) was no different when it came to assuming the objective reality of our world, as it would be in this one.

Physicalist views, such as behaviorism and functionalism reject dualism and claim that mental properties are identical to physical behaviors or physical properties; thoughts are identical to physical processes occurring in the brain. Both views constitute a rejection of substance dualism, or see the dualist mind/matter distinction as a conceptual division as opposed to an ontological one, reducing statements about thought and inner life or dreams as a form of linguistic shorthand for descriptions of physical states. One such thinker is Gilbert Ryle.

He rejects the mind-matter distinction as a category mistake, referring to it contemptuously as “the dogma of the Ghost in the Machine”. (Ryle, 2002, p.34) He claims however, to do so without reducing mental properties to material ones or vice-versa, which he argues is to treat them as “terms of the same logical type”.
He claims that:

“…the phrase, ‘there occur mental processes’ does not mean the same sort of thing as ‘there occur physical processes,’ and, therefore, that it makes no sense to conjoin or disjoin the two.” (Chalmers, 2002, p.37)

Therefore saying that ‘mental and physical processes occur’ is equivalent to saying that ‘people and airplanes fly,’ or ‘hamsters and computers run.’ In each example, the verb is applicable to people, airplanes, mental processes, physical processes, computers or hamsters, but the sense in which the verb applies is different. Airplanes fly, but people fly in a different sense. Whether the hamster or the computer run faster, is hard to determine because what it means for a hamster to run, is very different from what it means for a computer to run. So, for Ryle, the sense in which mental processes occur is not the same as the sense in which physical processes occur. In summarizing Ryle’s views David Chalmers writes:

“The mind is not to be seen as something distinct from the body and steering it from the inside, but as an aspect of the body’s own activities.” (Chalmers, 2002, p. 3);

Also adding the view that:

“the mind is an aspect of behavior…. Thus mind is seen as a public aspect of human activity, rather than as a private inner aspect.” (Chalmers, 2002, p.3)

Ryle therefore, would consider that talk about mental states is really, talk about behavior. The fundamental problem with this reduction is that assumes too much. Although lessons about mental properties can be learned from behavior and language, the entire phenomenal aspect of our inner lives is so much richer than the mere behaviors that we exhibit. If properties of the brain and properties of the mind are one and the same, then the example of dreaming shows a situation wherein mental properties do not translate readily into talk either of brain states or behavior. It goes against common intuitions (not merely philosophical ones,) to conflate mental states and the behaviors we instinctively feel are caused by such mental states. Hume in his Treatise on Human Nature states the epistemological problem of making such a reduction as follows:

“The powers, by which bodies operate, are entirely unknown. We perceive only their sensible qualities: and what reason have we to think that the same powers will always be conjoined with the same sensible qualities?” (Kramnick, 1995, p.200)

We cannot make inferences with any certainty that similar behaviors are always caused by similar mental states. The subjective character of consciousness is not merely a pattern of behavior, but instead, is limited by a positivistic tendency to exclude all but that, which is verifiable. In doing so, a mistake far worse than mere category error, occurs. Though Ryle denies that he makes a materialist reduction, in this text, he does err on the side of only acknowledging the ‘real’ existence of the physical. This neglects an enormous amount of mental activities that although private and non-verifiable, are nevertheless very real to those who experience them. Ryle cannot exorcise ‘the ghost in the machine’ without first establishing whether the ghost thinks it is in a machine, or the machine is in the mind of the ghost and its existence is as equally ephemeral. To assume there is only the machine, and the tasks it performs, is overly nihilistic and raises serious concerns about the richness of humanity’s inner lives were such a materialist outlook ever to catch on. Whilst mental properties may indeed be identical with physical properties, the way in which behaviorism and other physicalist perspectives seek to bridge this conceptual gap is one that looses too much of our everyday experience of having a mind. Though conscious states and brain states or behaviors may occur simultaneously this does not give us license to infer such a counter-intuitive causal link or to assume the direction of such causation. In my dream, such assumptions were made erroneously, because physical sciences lack the epistemic foundation to make metaphysical claims.

The rejection of substance dualism is justified and perhaps even long overdue, but physicalism has the potential to constitute an equally dangerous category error. By reducing our mental lives to physical processes, so much more is lost than in the reduction of physical properties, to properties of our mental experience. Where the physicalist reduction costs us our inner lives, the opposite reduction re-contextualizes our scientific knowledge, leaving our laws and governing principles intact, and integrating them into a more holistic worldview that neglects none of what we all intuitively know about ourselves as thinking beings.


Bibliography


Chalmers, D.J. (2002), Philosophy of Mind: classical and contemporary readings, Oxford University Press.

Descartes, R. Meditations on First Philosophy, excerpted in Chalmers, D.J. (2002), Philosophy of Mind: classical and contemporary readings, Oxford University Press, p.10-20

Hume, D. (1740) A Treatise on Human Nature, in Kramnick, I (Ed.) (1995) The Portable Enlightenment Reader, Penguin Books Ltd, London, p.195-202

Ryle, G. (1949) Descartes’ Myth, in Chalmers, D.J. (2002), Philosophy of Mind: classical and contemporary readings, Oxford University Press, p.32-38