Thursday, March 29, 2012

Difficulties in the way of a materialist view of the mind

To: Christopher J.
From: Geoffrey Klempner
Subject: Difficulties in the way of a materialist view of the mind
Date: 22 May 2007 10:09

Dear Chris,

Thank you for your email of 14 May, with your first essay for the Possible World Machine, in response to the question, 'What difficulties stand in the way of a materialist view of the mind, according to which thoughts, feelings and sensations are nothing more than processes in the brain?'

This is a very good piece of work which contains one completely novel argument (or, at least, novel to me) namely, your explanation of a possible source of resistance to materialism in the fact that even the most 'beautiful mind' is housed in a 'walnut shaped lump'. I have never thought about this before. How would one evaluate such a claim?

One way would be to conduct a thought experiment. Suppose that we are opening a human being's skull for the very first time. How would a brain have to look (i.e., how beautiful) in order to overcome our prejudices against materialism? What do you imagine? All I can think of is something that looks incredibly intricate, like the most exquisite piece of jewellery, with twinkly flashing lights - in fact the kind of thing that you get in sci-fi films about androids. (But then, of course, when we look at brain in a microscope all the beauty and intricacy is revealed - at least, so someone who has sufficient knowledge to understand what they are looking at.)

Another possibility is that when we open a person's skull we see - a beautiful face (or an ugly face, if the person is evil). What is more beautiful than a beautiful face, or more apt for being the seat of consciousness?

Another argument which you lay considerable stress on concerns the limits of empirical knowledge. Just as we cannot be certain that all swans are white, on the basis that all the swans we have so far observed are white, so we cannot be certain that (what exactly?) on the basis that all brains we have so far observed lack (what exactly?).

You can see the difficulty I have with this. There is a real possibility, given our lack of knowledge at the present time, that the brain is not a Dennett style super-computer but merely a relay mechanism - just as Descartes believed - which responds to a non-observable input, translating these impulses into neuron firings. Suppose we were to discover this. Would that prove Cartesian dualism? In the scenario which I am envisioning, neuroscientists and physicists agree that there exists a force which cannot be detected by any physical instruments that they have been able to construct, whose only effects are on a functioning brain. In a nod to philosophy, they attribute this force to 'soul substance'.

But it is not Descartes' soul. The problem is that Descartes' argument for mind-body dualism can be run with whatever science discovers about our objective nature. Empirically postulated soul substance is invisible, so the 'ugly brain' problem does not arise. Yet we still have to deal with the Cartesian intuition that I would know that I exist and have consciousness, even if an evil demon was deceiving me into thinking that there existed a world of objects in space, and therefore that what I am essentially cannot be identical with anything belonging to that world.

I recognized your argument from paragraph two as Frank Jackson's notorious 'Mary' argument. There is more on this argument in Samuel Michaelides' fellowship dissertation which you will find in the Pathways Essays Archive http://www.philosophypathways.com/essays/.

You also try out David Chalmers' zombie argument. Having read his recent interview in Philosophy Pathways http://www.philosophypathways.com/newsletter/issue123.html I have begun to wonder whether Chalmers really wants a non-physical soul-entity, or is merely objecting to attempts at psycho-physical reduction. In paragraph one, you talk of 'physical processes which can be subject to empirical analysis'. This is Dennett territory: mapping out the 'program' of the human brain. But there is another possibility - that the way the brain realizes mental states turns out to be indecipherable by any physical process - short of duplicating the complexity of that very brain. Why should we assume that if materialism is true, then it will be possible at some time - however far in the future you like - to 'read' the contents of a brain from observation of its physical states?

On a 'connectionist' view of the nature of the brain, there is no brain program but only a continually refined adjustment amongst the billions of neurons. There is just one way to 'access' the contents of a brain, and that is to be the individual whose brain it is. (I explore this possibility in my piece, 'Truth and subjective knowledge' http://klempner.freeshell.org/articles/shap.html.) In other words, you can be a kind of materialist ('soft materialist' sounds like a good term, by contrast with your 'hard materialist') while admitting that there will always be an 'explanatory gap'. What gives one the right to call oneself 'materialist' would be general arguments establishing that the brain is capable of 'realizing' the phenomena of consciousness while at the same time admitting that we will never be in a position to explain how specific patterns realized in matter are related to the quality of a person's mental life.

All the best,

Geoffrey