Sunday, 13 May 2012

In Search of the Mind: An Introduction to the Hard Problem of Consciousness - Part Two



Functionalism - Unfinished Business
In Part One, we outlined that the Hard problem of consciousness is explaining how the subjective feelings of 'what it is like to be conscious' can arise from physical molecules and neurons in the brain. We also critiqued the Functionalist approach to solving the issue, considering Jackson's thought experiment of Mary the colourblind scientist. 


The Functionalist approach conceives of the mind as a separate 'virtual' layer of symbol manipulation-based information processing implemented in a Turing Machine. That is, cognition involves the amodal representation of semantic symbols based on rules or syntax. An important implication of this is that if the mind is classically computational, it can, in theory, be emulated  on a classical computer. Before we consider materialist approaches that take the Hard Problem seriously, I think this requires some further thought. 


To say that the mind is classically compuational is not a given. There are many reasons why we should think that the mind does not process abstract symbols like a computer. I have touched on these issues in previous blogs on Embodied Cognition here and here and also indirectly with regards to Neural Networks, which provides an alternative paradigm for understanding the mind computationally.  


One common criticism, worth mentioning is John Searle's 'Chinese Room' thought experiment: 


Briefly, Searle asks us to imagine being in a room where pieces of paper are posted through containing a question in a language we do not understand, say Chinese (apologies for the Westernization of this example). Although we don't understand the symbols on the paper, we have a set of rules which show us the correct symbols to write in response to whatever symbols are posted through. We then write down these symbols and post the 'answer' back. 


The point, is that to the person outside the room, the responses would indicate that the person inside understands the questions being asked. Clearly, however, this is not the case and the person inside is simply constructing new symbols based on given rules.  Essentially, this is analogous to how a computer works. In other words, there is no concscious semantic understanding of the referential meaning of the symbols involved - its is simply mindless processing.


Suffice to say, to argue the mind is analogous to a computer is a big assumption with a lacking evidence base to support it.

3. Identity and the Emergent Mind  - Saviours of the Physicalist Paradigm?
Clark’s 1995 and Hardcastle’s 1996 identity theories attempt to overcome previous problems, conceiving of consciousness as a posteriori identical to the brain. As with the Kripkean response to Jackson’s argument, they get around the problem of the unpredictability of phenomena from the physical processes. However, Chalmers 1996 responds; that “…functional states are conscious states is taken as a brute fact…”, thus this does not explain how or why they are identical.  The same applies to the non-reductive physical accounts (Murphey & Brown 2007) arguing mind emerges and supervenes on the brain. Kim (1993) argues the need to explain why consciousness is fundamental, presents with an impossibility; a brute and in principle unexplainable relationship which we must accept ‘with natural piety’”. I agree. But, as with physics, we must still justify our decision to create fundamental laws.

3b. Death by Occam’s razor?
Perhaps the materialists’ strength lays in the principle of Occam’s Razor. Why not shave off the unnecessary assumptions of dualism and stick to our materialist guns? However, materialism hasn’t delivered - it confuses ontology with provenance and tries to sneak around the explanatory gap.
At this point, as Tim Crane 2001 notes, the Hard Problem may be split between physicalists continuing to try to bridge the gap and property dualists or neutral monists explaining how we justify decisions to dub consciousness a fundamental law or part of a further neutral substance. I will focus on the former as this is how Chalmers conceptualises the hard problem. However, I feel it necessary to make our fifth and sixth ‘cherished assumptions’ related to the latter; 

‘The mind is not physical yet causal (the rejection of epiphenomenalism)’ 

‘the universe is causally closed.’
 
Briefly, the remaining problems for non-physicalists, will be to explain causal role of a non-material consciousness in a causally closed universe without breaking the laws of nature (See Chalmers 1996 for his summary and solution).

4. What easy problems?
Lowe (1995), Velmans (1995) and Libet (1996) all take issue with the ‘easiness’ of the easy problems, arguing awareness also entails qualia, thus the hard problem is even harder than anticipated, extending to the ‘easy’ problems.

However, I agree with Chalmers’ 1996 that this boils down to an argument of language. The hard problem remains explaining qualia - if awareness entails qualia then the only easy part is explaining the non-experiencing aspects i.e. processes.

5. What makes the hard problem so hard?
I have attempted to demonstrate the hardness of the problem in terms of the explanatory gap and failures of the materialists to bridge it. It is important to provide an overview in addition to Chalmers’ arguments, as to why we would think it to be hard in the first instance.
Robinson (1996) argues we cannot explain consciousness within the current conceptual framework, since some property of subjective experience lacks structure. Briefly, he argues:

“If  a  regularity  involving  a  given  kind  is  to  be  explained,  the  kind must  be expressible as a structure.” but “Among the properties of conscious experiences, there is always at least one that has no structural expression.”

Whilst we can explain pain in terms of C fibres firing, this is due to its structure. However, the subjective aspect of feeling pain lacks such structure, thus presents a problem.

Others (e.g. Lycan 1996) appeal to the ‘Conservation of Energy Argument’. Assuming the universe is causally closed, how is causal interaction between mind and body explained, without breaking the conservation of energy principle? Putting experience outside this causally closed domain, we must accept epiphenomenalism or try to sneak it in and out via some kind of ‘Quantum Tunnelling’ (Hameroff 1998). Keeping experience within, requires a challenging justification; Russellian Monism. Maxwell (1978), Lockwood (1989) and Chalmers (1996) attempt this, based on Bertrand Russell (1927), arguing physics only tells us about the causes and effects of basic entities, not their metaphysical nature, hence, we should view experience and matter as part of a further neutral substance.

Other works deserving of mention include Warner’s ‘Problem of Incorrigibility’, McGinn’s (1995) problem of ‘consciousness as non-spatial’, Gray’s (2004) problem of evolution of consciousness and those that rest on insights Quantum Mechanics may yield (e.g. Stapp 1993 and Bilodeux 1996). These all provide examples of what makes the Hard Problem hard. 

Seven ‘cherished assumptions’
I have tried to demonstrate consciousness does constitute a genuinely hard problem by breaking the problem down into six ‘cherished assumptions’:

1) consciousness itself exists
2) consciousness is physical and thus can be explained reductively
3) ‘the whole is no more than the sum of its parts’
4) ‘the imaginable existence of zombies’
5) ‘The mind is not physical yet causal (the rejection of epiphenomenalism)’
6) ‘the universe is causally closed.’

The difficulties that arise in our current inability to decide whether to accept or reject these assumptions, collectively lead to the trickiness of the mind-brain debate and thus the Hard Problem.

One final ‘cherished assumption’:

‘Russillian Monism or an equivalently radical theory is justified in breaking or accepting certain ‘cherished assumptions’ in the hope of increasing explanatory power’.

Reductionism’s attempts fail to kill off competition with Occam’s Razor, thus, the hard problem remains very hard indeed.

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