David Nyman wrote:
> 2009/9/13 Brent Meeker <meekerdb.domain.name.hidden>:
>
>> You regard "doing the same computation" as a purely formal (=
>> non-physical) critereon, but I think this is specious. It seems right
>> because we talk about "a computation" at a very high level of
>> abstraction. But when we ask what makes this causal sequence or that
>> process a "computation", in contrast to other sequences or processes
>> that aren't, we find that we must describe the computation as having an
>> effect in the larger physical context. So to say that two physical
>> processes realize the same computation is formal, but it is not *only*
>> formal. It is implicitly physical too.
>
> Yes, of course I know it's *implicitly* physical, that's the problem.
> The point is that evaluating CTM as a physical theory of mind
> necessitates making the relation between experience and process
> *explicitly* physical, and actually attempting this inevitably results
> in a failure to discover any consistent association between specific
> physics and specific experience.
That seems like a category mistake. You're asking for and explicitly physical relation
between a computation and a physical process. But a computation isn't physical; the
relation has to relate something non-physical to the physical - so obviously it relates
the non-physical things like potential action in a context or evolutionary function to the
physical process.
>This is not merely unfortunate, it
> is a direct consequence of the arbitrariness of physical
> implementation central to the hypothesis.
I don't see the problem. There are arbitrarily many computations of the same function too.
Brent
>
> Your point about having an effect in the larger context is
> unproblematic as long as it is considered from a third person
> perspective. From this perspective there's no difficulty about the
> physics of the realisation, since what is relevant is simply that it
> fulfil the formal criteria in terms of *some* physical implementation,
> no putative experiential aspect being at issue. I agree that this is
> the right criterion to discriminate physical computational systems of
> interest from those that are inconsequential (i.e. rocks etc.). The
> point at issue with Peter, however, relates to the putatively
> homogeneous experiential correlate of the heterogeneous physical
> implementations, not their status as purely physical processes. We
> seem to be discussing two different issues.
>
> Consider what motivates CTM in the first place. The mind-body problem
> seems in many ways as impenetrable as ever, despite all advances in
> brain science and on the wider theoretical and experimental front.
> But wait a moment, we have a nice theory of computation, and we know
> how to apply it to computers and their programming. We even indulge
> in metaphor about the thoughts and intentions of our devices (I know I
> do). Maybe that's what the mind is? Wizard wheeze! But wait again
> - when we actually think about what these beasties are up to
> physically in their various realisations - mechanical, hydraulic,
> electronic, pneumatic - there's a whole raft of promiscuous,
> uncorrelated physical processes going on down there, and none of them
> much like our own wetware version. How can we get a consistent
> physics of consciousness out of this? What to do? I know - it
> doesn't matter!
>
> Great physical theory, eh?
>
> David
>
>> David Nyman wrote:
>>> 2009/9/11 Flammarion <peterdjones.domain.name.hidden>:
>>>
>>>
>>>>> I'm not sure I see what distinction you're making. If as you say the
>>>>> realisation of computation in a physical system doesn't cause
>>>>> consciousness, that would entail that no physically-realised
>>>>> computation could be identical to any mental state.
>>>>>
>>>> That doesn't follow because causation and identity are different
>>>> The realisation could be consciousness (fire IS combustion)
>>>> without causing it (fire CAUSES smoke but it not smoke)
>>>>
>>> So what did you mean the reader to conclude from your original
>>> argument? You concluded that the realisation of a computation doesn't
>>> cause consciousness. But did you also mean to imply that nonetheless
>>> the realisation of a computation IS consciousness? If so, why didn't
>>> you say so? And how would that now influence your evaluation of CTM?
>>>
>>>
>>>>> This is what
>>>>> follows if one accepts the argument from MGA or Olympia that
>>>>> consciousness does not attach to physical states qua computatio.
>>>>>
>>>>>
>>>> I find them both quite contestable
>>>>
>>> If you would risk saying precisely why, you might have a counter-argument.
>>>
>>>
>>>>> I agree. Nonetheless, when two states are functionally equivalent one
>>>>> can still say what it is about them that is physically relevant. For
>>>>> example, in driving from A to B it is functionally irrelevant to my
>>>>> experience whether my car is fuelled by petrol or diesel. But there
>>>>> is no ambiguity about the physical details of my car trip or precisely
>>>>> how either fuel contributes to this effect.
>>>>>
>>>> One can say what it is about physical systems that explains
>>>> its ability to realise a certain computation. One can't say that
>>>> there is anything that makes it exclusively able to. Equally
>>>> one can explain various ways of getting from A to B, but
>>>> one can't argue that there is only one possible way.
>>>>
>>> The point at issue is not whether there is only one way to realise a
>>> computation, or to get from A to B. The point is that in the case of
>>> the journey, the transition from physical irrelevance to relevance is
>>> at the point where the physical result emerges as identical - i.e. as
>>> the same journey form A to B. In the case of the computation, no such
>>> physical identity of result ever emerges; all you have is a collection
>>> of heterogeneous physical processes, each merely *formally* identical
>>> to a given computation. It is a further - and physically entirely ad
>>> hoc - assumption that this heterogeneity of physical states is
>>> homogeneous with a single experiential state.
>>>
>>>
>>>>> Yes, I agree. But if we're after a physical theory, we also want to
>>>>> be able to give in either case a clear physical account of their
>>>>> apprehensiveness, which would include a physical justification of why
>>>>> the fine-grained differences make no difference at the level of
>>>>> experience.
>>>>>
>>>> THat would be because they make no computational difference,
>>>> if CTM is correct.
>>>>
>>> If all you have to offer is circular arguments we shall simply go
>>> round in circles.
>>>
>>>
>>>>> I can only suppose that complete arbitrariness would be a random
>>>>> association between physical states and mental states. This is not
>>>>> what is meant by arbitrary realisation. What is meant is that the
>>>>> requirement that a physical system be deemed conscious purely in
>>>>> virtue of its implementing a computation rules out no particular kind
>>>>> of physical realisation. Consequently a theory of this type is
>>>>> incapable of explicating general principles of physical-mental
>>>>> association independent of its functional posit.
>>>>>
>>>> It isn't. Why is that a problem?
>>>>
>>> The problem is that theories which aren't reducible to fundamental
>>> physics don't warrant consideration as physical theories. This is
>>> amply demonstrated by the fact that, when reduced to a physical
>>> interpretation, CTM is in fact shown to entail gross implausibilities.
>>>
>>>
>>>>> Yes, but the upshot is that CTM is reduced to the theory that
>>>>> conscious states can be associated with material systems only in a
>>>>> manner that ex hypothesi must obscure any prospect of a general
>>>>> reduction of their detailed material causes, because any such causes
>>>>> could only be specific to each realisation.
>>>>>
>>>> You can have as many material details as you like
>>>> so long as they are relevant to explaining the computation.
>>>>
>>>> Maybe you are hung up on causes. CTM is really an identity theory--
>>>> mental
>>>> states are identified with functional states. It's not fire-causes-
>>>> smoke causation.
>>>>
>>> I'm fine with mental states being identified with functional states.
>>> The problem is one functional state reduces to multiple physical
>>> states. Hence CTM entails that one experiential state reduces to
>>> multiple physical states, without being able to give any consistent
>>> physical, as opposed to formal, criterion for such identity.
>> You regard "doing the same computation" as a purely formal (=
>> non-physical) critereon, but I think this is specious. It seems right
>> because we talk about "a computation" at a very high level of
>> abstraction. But when we ask what makes this causal sequence or that
>> process a "computation", in contrast to other sequences or processes
>> that aren't, we find that we must describe the computation as having an
>> effect in the larger physical context. So to say that two physical
>> processes realize the same computation is formal, but it is not *only*
>> formal. It is implicitly physical too.
>>
>> Brent
>>
>
> >
>
--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups "Everything List" group.
To post to this group, send email to everything-list.domain.name.hidden
To unsubscribe from this group, send email to everything-list+unsubscribe.domain.name.hidden
For more options, visit this group at
http://groups.google.com/group/everything-list?hl=en
-~----------~----~----~----~------~----~------~--~---
Received on Sun Sep 13 2009 - 17:05:38 PDT