On 8/23/2014 9:09 AM, David Nyman wrote:
On 23 August 2014 05:02, meekerdb <[email protected] <mailto:[email protected]>>
wrote:
/What we observe in practice are physical devices of various kinds
(indeed, in
principle, indefinitely many kinds) that we accept FAPP as adequately
instantiating particular classes of computation within certain fairly
stringent
limits./
/
/
/What we observe, aside from observing our own thoughts and maybe even
then, is
always theory laden. Partly we see the world through a theory of objects
that
evolution has provided us, sort of naive physics, but a theory nonetheless
as
optical illusions demonstrate./
And the relevance of this remark to my point is what, precisely?
Just a cautionary remark that observing a physical device already involves assumptions
that it is an experience that can in principle be shared and agreed on by other observers
- i.e. that it assumes some physics.
/To put it another way, we are prepared to interpret the normal physical
behaviour of such devices *as if* it instantiated the mathematical
notion of
computation./
/
/
/Right, because it usually (modulo a dropped bit or so) does./
Obviously. And your point is...?
/These considerations should make it clear that any description of the
normal
behaviour of a physical device as computation can only be in a sense
that is,
ultimately, metaphorical./
/
/
/I think you are too hung up on ontology. You denigrate everything that's
not in
terms of the ur-stuff of (some unknown) true ontology as metaphor or
fiction. Why
not accept that knowledge, including knowledge of ontology, is always
provisional
and uncertain and it's best to think of it as a model summarizing our best
idea -
but not necessarily the one TRUE idea./
Maybe you are getting a little too hung up on what you imagine me to be hung up on. If
that is the case, it might make you somewhat unreceptive at the outset to what you
assume to be my line of argument. I'm not trying to grind any axe in particular but only
to articulate what I suspect are sometimes unrecognised assumptions as clearly as I can
and then examine the consequences. Of course I may well be wrong on any point and so my
aim is to encourage discussion from which I might learn.
In this particular case what I'm driving at isn't that either matter or computation need
be considered as some kind of mystical "ur-stuff" (whatever that would be). What I'm
questioning is whether it is really coherent to attribute *first-person* consciousness
to "computation" against the background of any theory that is committed to a physically
primitive level of explanation.
You're saying it may be incoherent to reduce consciousness to computation, if computation
is reducible to physics? Why would that be incoherent? Must 'reduction' necessarily be
reduction to the bottom to be coherent? Or are you assuming consciousness can't be
reducible to physics therefore it can't be reducible to some intermediate (computation)
that risks be reducible to physics?
I know you cross swords with Bruno over the meaning of primitive in this context, but I
don't see why this has to be problematic. Primitive simply means the level of
explanation to which it is *assumed* every other level can be reduced.
I think we only "cross swords" when Bruno implies that any reduction of consciousness to
physical processes is the same as asserting that some (undefined) physics is primitive.
The way theoretical physics has developed over the last century I wouldn't be surprised if
someone developed a fundamental theory of physics based on homotopy theory or knots or
numbers. But it wouldn't affect the reduction of chemistry to physics and it might not
affect the reduction of computation to physics. I take "physics" to mean the most
fundamental science of what we can empirically agree on - whatever it's ontology is. I
think Bruno only differs in that he thinks we can agree on things that are not empirical,
like arithmetic.
The point is not that we can know any particular theory of this sort to be TRUE, but
only that we should rigorously pursue its consequences *as if it were*.
My point then is that we should start by treating a theory of physical primitivism "as
if true". If so, it is only consistent to suppose that any phenomenon under
consideration in terms of that theory must be assumed to be adequately and fully
accountable (at least in principle) at its lowest level of physical reduction. You
persistently demur from this line of argument, but I think you miss my point, which is
entirely harmless in every case except (I contend) that of the "1p part" of
consciousness. It is entirely possible to understand a physically-instantiated
computation (and hence, on CTM, an associated state of consciousness) to be the same
physical process regardless of the "level of reduction" at which it is considered. After
all, any such "level" is, in the end, merely a term of art associated with the theory in
question. But what I'm questioning is whether it is coherent to (tacitly) treat the 1p
part as merely such a term of art.
?? Does "term of art" imply a third person description?
My sense is that you equivocate on this, because if we only consider the 3p part (as in
your analogy of the Mars Rover) the point (i.e. 3p-reducibility) is indeed harmless. But
the 1p part resists 1p-reduction. It stubbornly is what it is. Hence my question
essentially is about the kind of theory required to make sense of associating an
irreducible 1p part with a reducible 3p part. AFAICS such a question cannot even be
posed coherently in terms of physical primitivism.
Suppose that you have a theory which reliably tells you which 1p qualia go with which 3p
brain processes (the engineering level solution to the mind-body problem). Does that
"make sense of associating an irreducible 1p part with a reducible 3p part."? Or are you
saying that such an association can't be a brute fact?
Indeed you have suggested that it is unreasonable to ask for this. What inclines me to
Bruno's ideas (assuming CTM of course) is that this particular question may be better
posed in terms of a theory that takes computation, not physics, as its primitive.
Yes, I agree that it might be. But even if it provides a better answer to the relation of
qualia to brains, that doesn't make it a better TOE if it can't solve the "white rabbit"
problem. It will just have traded one problem for another.
I think the remainder of your remarks equivocate on precisely this 3p-1p distinction, so
I won't comment on them specifically. If I've read you wrongly on this I'd be grateful
for clarification.
No, I think that's a fair reading. As you note, I don't think it's possible to have a
1p-reduction of the 1p part (if I understand what you mean by 1p-reduction). I think the
engineering level solution may be the best that can be done.
Brent
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