To: Louis G.
From: Geoffrey Klempner
Subject: Difficulties for a materialist view of the mind
Date: 11 January 2007 12:17
Thank you for your email of 31 December, with your notes on unit 3 of Possible World Machine, and your first essay, 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 ultimately nothing more than processes in the brain?'
You have chosen to give a survey of the different theories or 'isms' that have been put forward in order to account for the phenomenon of mind. You have covered the majority of the main alternatives. One thing that it is important to note is that the character of the problem changed quite profoundly with Descartes who was the first to introduce the idea of substance dualism, with physical and mental substance having distinct and non-overlapping essential properties.
In some ways, recent philosophy of mind has returned to something like an Aristotelian view, which suggests the possibility of a non-reductive supervenience theory consistent with materialism which rejects the possibility of reducing the self or mind to a 'program' as AI theorists like Dennett believe. The idea is that there is, ultimately, 'nothing but' the physical, but these physical events, in the case of mind, can only be described in mental language. Mental events 'supervene' on physical events, but there is, in principle, no 'translation' between the language of physics and the language of psychology.
Neural networks are one possible model for this alternative approach. However, it is not clear at the present time whether the idea of a neural network will in fact prove sufficient to explain the way the brain works, or whether there are other elements involved such as quantum effects or even, as Thomas Nagel has hypothesised, the possibility of going beyond physics altogether.
That might involve explaining the source of the 'psycho-physical nexus' in a theory which is neither strict materialism nor dualism but closer to Whitehead's panpsychism in holding that every physical event has, in some sense, a mental aspect.
In this difficult area, one should not be too quick to dismiss any proposal.
The Walkabout story is intended to raise questions about materialism. However, the protagonist herself succeeds after some struggle in formulating a response which resists the dualist alternative. The upshot is that no mere experience, however described is sufficient in itself to refute materialism.
How one uses the terms 'soul', 'self' and 'mind' is a matter of theoretical and practical utility, which depends on the particular theory which you happen to favour.
I want to continue the discussion where your essay leaves off, because I am largely in agreement with the view that there is insufficient evidence at the present time that the explanation of the course of our subjective experiences could be reduced to physics and chemistry.
Without the mental aspect, the psychological angle, the observed brain effects are, in your nice simile, like the track of a pin-ball in a pinball machine, apparently random and chaotic.
However, this is not an argument in principle against the AI approach, which likens thought to the running of a program. That's just how things would be, the AI theorist will say (I am thinking, for example, of Daniel Dennett 'Consciousness Explained'). However, the AI theorist is wrong to claim that this is how things must be. At the present time we just don't know. That is to say, it is an empirical question to which we do not, at the present time, know the answer, whether the brain works like a computer or in some radically different way.
However, that leaves out of the picture the biggest challenge that has been raised to materialism, explaining the phenomenon of qualia. I alluded to Chalmers contribution to the debate in my editor's introduction. It seems that it would be possible for a physically identical zombie version of you to go though the physical processes you describe - such as uttering 'ooh' and 'aah' when the islands come into view, or weeping when the radio is turned on - without there being or happening anything 'inside' apart from the physical and chemical processes occurring in the zombie's brain and nervous system. 'I know from my own case', one feels like saying, 'that there is more to me than the physical!'
The problem with this argument - not necessarily an insuperable problem, but you will have to decide that for yourself - is that by hypothesis the zombie version of you (on Twin Earth) also wrote your essay, describing in pregnant detail the riches of your inner experiences and using this as an argument against materialism.
All the best,