[Wittrs] Re: Searle's Revised Argument -- We're not in Syntax anymore!
- From: "SWM" <SWMirsky@xxxxxxx>
- To: wittrsamr@xxxxxxxxxxxxx
- Date: Mon, 24 May 2010 18:16:49 -0000
Searle's new argument as he presents it in the APA address recently referenced
by Gordon. (My comments follow the argument, below.)
http://users.ecs.soton.ac.uk/harnad/Papers/Py104/searle.comp.html
This brief argument has a simple logical structure and I will lay it out:
1) On the standard textbook definition, computation is defined syntactically in
terms of symbol manipulation.
2) But syntax and symbols are not defined in terms of physics. Though symbol
tokens are always physical tokens, "symbol" and "same symbol" are not defined
in terms of physical features. Syntax, in short, is not intrinsic to physics.
3) This has the consequence that computation is not discovered in the physics,
it is assigned to it. Certain physical phenomena are assigned or used or
programmed or interpreted syntactically. Syntax and symbols are observer
relative.
4) It follows that you could not discover that the brain or anything else was
intrinsically a digital computer, although you could assign a computational
interpretation to it as you could to anything else. The point is not that the
claim "The brain is a digital computer" is false. Rather it does not get up to
the level of falsehood. It does not have a clear sense. You will have
misunderstood my account if you think that I am arguing that it is simply false
that the brain is a digital computer. The question "Is the brain a digital
computer?" is as ill defined as the questions "Is it an abacus?", "Is it a
book?", or "Is it a set of symbols?", "Is it a set of mathematical formulae?"
5) Some physical systems facilitate the computational use much better than
others. That is why we build, program, and use them. In such cases we are the
homunculus in the system interpreting the physics in both syntactical and
semantic terms.
6) But the causal explanations we then give do not cite causal properties
different from the physics of the implementation and the intentionality of the
homunculus.
7) The standard, though tacit, way out of this is to commit the homunculus
fallacy. The humunculus fallacy is endemic to computational models of cognition
and cannot be removed by the standard recursive decomposition arguments. They
are addressed to a different question.
8) We cannot avoid the foregoing results by supposing that the brain is doing
"information processing". The brain, as far as its intrinsic operations are
concerned, does no information processing. It is a specific biological organ
and its specific neurobiological processes cause specific forms of
intentionality. In the brain, intrinsically, there are neurobiological
processes and sometimes they cause consciousness. But that is the end of the
story.\**
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
My Comments:
1 & 2 hinge on a definitional claim, i.e., that textbooks say this is how we
define "computation". Recall that the argument for what Searle calls "Strong
AI" is not about definitions, however but about what computers, as actual
machines, can be brought to do.
3 tells us that, because something is not in accord with a particular
definition (though we know definitions may vary, both by source and in terms of
the use context) we should draw a conclusion about an object that is sometimes
defined in the way Searle reports the definition. In essence he is asking us to
commit to the definition he has invoked without giving a reason why we need to
do that.
In item 4 Searle argues that the failure of the definition he has focused on to
work in a particular case is evidence of a failure of the thing defined to
operate in a certain way. Yet this assumes that, just because the definition he
has fixed on seems to break down here, there are consequences for the thing
being defined (even if, relying on a different definition, those consequences
would not be seen to obtain, i.e., a physicalist account would not be subject
to the same problem).
In item 5 he is right to note that by "computer" we don't mean anything that
can be called that by some expansion of the term's meaning. However, he seems
to be confusing the homunculus issue when he says we need something along these
lines, i.e., an observer/user, to make a system a "computer". In fact, we don't
need anything of the sort for brains so why presume we need that for a computer
engaged in doing whatever it is brains do?
His point in item 6 is really because, when considering computers qua brains,
we are not interested in computation qua computation (as a process aimed at
arriving at a calculation for some purpose to which we mean to put that
calculation to) but in computation as processing in the way a brain might
operate, i.e., implemented computuational processes! He errs every time he
mixes up the activity of calculating with the activity of information
processing as performed by the physical elements of brains AND computers.
In 7 he is once again confusing levels of description. A user/observer is
relevant to a computer as a tool but the brain is not its user/boserver's tool
but the source or medium of its user's existence.
Finally in 8 we again find him slipping meanings. If by "information
processing" he only means whatever it is people do with computational tools
like computers and calculators, then he's right. But that isn't what we mean by
"information processing" when speaking about brains! His assertion that the
biological nature of the brain is paramount is being assumed here, not
demonstrated, as is his assumption as to what "intentionality" is. This again
points up his inherently mysterian concept of mind, a concept that while
explicitly denying dualism finally hinges on it because of a commitment to a
fundamental irreducibility of mind to its constituents, even while he persists
in agreeing that brains do what he wants to say computers can never do.
SWM
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