On 02 Mar 2014, at 18:51, Stathis Papaioannou wrote:
On 2 March 2014 22:18, Bruno Marchal <marc...@ulb.ac.be> wrote:
>
> On 02 Mar 2014, at 08:09, Stathis Papaioannou wrote:
>
>
>
> On 1 March 2014 01:40, Bruno Marchal <marc...@ulb.ac.be> wrote:
>
>>> If you start with the assumption that the physics relevant to
brain
>>> function is not computable then computationalism is false: it
would be
>>> impossible to make a machine that behaves like a human, either
zombie
>>> or conscious.
>>
>>
>> I agree with you, the physics *relevant* to brain function has to
be
>> computable, for comp to be true. But the point is that below the
>> substitution level, the physical details are not relevant. Then
by the
>> FPI,
>> they must be undetermined, and this on an infinite non computable
domain,
>> and so, our "computable brain" must rely on a non computable
physics, or a
>> non necessarily computable physics, with some non computable
aspect. This
>> is
>> what comp predicts, and of course this is confirmed by QM. Again,
>> eventually, QM might to much computable for comp to be true. That
is what
>> remain to be seen.
>>
>>
>>> What I mean by functionalism is that the way the brain processes
>>> information, its I/O behaviour, is what generates mind. This
implies
>>> multiple realisability of mental states, insofar as the same
>>> information processing could be done by another machine. If the
>>> machine is a digital computer then functionalism reduces to
>>> computationalism. If the brain utilises non-computable physics
then
>>> you won't be able to reproduce its function (and the mind thus
>>> generated) with a digital computer, so computationalism is false.
>>> However, that does not necessarily mean that functionalism is
false,
>>> since you may be able to implement the appropriate brain function
>>> through some other means. For example, if it turns out that a
digital
>>> implementation of the brain fails because real numbers and not
>>> approximations are necessary, it may still be possible to
implement a
>>> brain using analogue devices.
>>
>>
>> OK, but that functionalism seems to me trivially true. How could
such
>> functionalism be refuted, if you can invoke arbitrary functions?
>> (Also, "functionalism" is used for a stringer (less general)
version of
>> computationalism, by Putnam, so this use of functionalism is non
standard
>> and can be confusing.
>> Last remark, I am not sure that the notion of information
processing can
>> make sense in a non digital framework. In both quantum and
classical
>> information theory, information is digital (words like bits and
qubits
>> come
>> from there).
>
> I think functionalism is true, but it's not obviously true, at
least to most
> people. It could be that the observable behaviour of the brain is
reproduced
> perfectly but the resulting creature has no consciousness or a
different
> conscious.
>
>
> What if someone says that the function of the brain is to provide
> consciousness. Is that functionalism?
> What if someone says that the function of the brain is to link a
"divine"
> soul to a person through a body?
> What is a function?
No, a function is an observable pattern of behaviour.
You do use "function" in a non standard sense.
Functionalism says that if you replicate this, you also replicate
the mind. You need to replicate not only a special behaviour (which
could be quite easy) but all outputs for all inputs.
At all levels. Your functionalism is just what is called "mechanism".
That generalizes indeed "digital mechanism", that is comp.
It is not "functionalism" in the sense of philosopher of mind, where
it means computationalism, with a fuzzy fixed level.
> That would be the case if consciousness were substrate-dependent.
>
>
> But you can put the substrate in the function. A brain would have
the
> function to associate to that substrate the experience. How could
I say no
> to the doctor who guaranties that all the function of the brain are
> preserved.
> The term function, like set, is too general, to much powerful.
Then I'm using it in a somewhat precise sense as above.
Unfortunately, "observable pattern of behavior" is not that much
precise. "observable" is a complex epistemic notion for example. But I
got it.
> It could also be that the behaviour cannot be reproduced by a
computer
> because the substitution level requires non-computable physics (true
> randomness, real numbers, non-computable functions), but it could be
> reproduced by a non-computational device. So there are these
possibilities
> with brain replacement:
>
> (a) the behaviour is not reproduced and neither is the
consciousness;
>
>
> = ~ BEH-MEC
>
>
> (b) The behaviour is reproduced but the consciousness is not
reproduced;
>
>
> ~ comp.
>
>
>
> (c) The behaviour is reproduced and so is the consciousness;
>
>
> = comp, unless it is the consciousness is the one by an impostor.
>
>
>
> (d) The behaviour is not reproduced but the consciousness is
>
>
> = "bad" substitution.
>
>
>
>
>>> What can be proved is that if consciousness is due to the brain
then
>>> replicating brain function in some other substrate will also
replicate
>>> its consciousness.
>>
>>
>> OK. What I meant is that we cannot prove that consciousness is
due to the
>> brain.
>
> Yes, a dualist, for example, could consistently deny fuctionalism,
>
>
> Not sure. It depends on how you define function.
>
>
>
> but someone who believes that consciousness is due to the brain
could not.
>
>
> Most dualist believes that consciousness is due to the brain. They
will
> usually deny that the functional relation can be obtained with
this or that
> type of functions, but to throw out all functions, makes their
theory
> spurious. There will lost both interactionism and epiphenomenalism.
>
> Maybe you are on some idea, but you should take another word, as in
> philosophy of mind, functionalism is used for Putnam's
computationalism. I
> do see vaguely what you mean, but it is still hard to define this
precisely.
> It corresponds to the infinities of weakening comp, by adding
oracle, or
> things like that.
> My old definition of comp was En (functionalism is true at level
n), making
> functionalism à-la Putnam a restricted from of comp. Your terming
is non
> standard and can lead to confusion, imo. You might use "mechanism"
instead,
> with the idea that not all machines are digital indeed.
I like this account of functionalism from the International
Encyclopedia of Philosophy:
quote>
Consider, for example, mouse traps. Mouse traps are devices for
catching or killing mice. Mouse traps can be made of most any
material, and perhaps indefinitely or infinitely many designs could
be employed. The most familiar sort involves a wooden platform and a
metal strike bar that is driven by a coiled metal spring and can be
released by a trigger. But there are mouse traps designed with
adhesives, boxes, poisons, and so on. All that matters to
something's being a mouse trap, at the end of the day, is that it is
capable of catching or killing mice.
Contrast mouse traps with diamonds. Diamonds are valued for their
hardness, their optical properties, and their rarity in nature. But
not every hard, transparent, white, rare crystal is a diamond--the
most infamous alternative being cubic zirconia. Diamonds are carbon
crystals with specific molecular lattice structures. Being a diamond
is a matter of being a certain kind of physical stuff. (That cubic
zirconia is not quite as clear or hard as diamonds explains
something about why it is not equally valued. But even if it were
equally hard and equally clear, a CZ crystal would not thereby be a
diamond.)
These examples can be used to explain the core idea of
functionalism. Functionalism is the theory that mental states are
more like mouse traps than they are like diamonds.
Hmm.... This is quite fuzzy and level dependent.
That is, what makes something a mental state is more a matter of
what it does, not what it is made of.
OK. But then functionalism is just mechanism.
This distinguishes functionalism from traditional mind-body dualism,
such as that of René Descartes, according to which minds are made of
a special kind of substance, the res cogitans (the thinking
substance.)
And here I think that Descartes abandoned that idea, but that's a bit
beside the topic.
It also distinguishes functionalism from contemporary monisms such
as J. J. C. Smart's mind-brain identity theory. The identity theory
says that mental states are particular kinds of biological states--
namely, states of brains--and so presumably have to be made of
certain kinds of stuff, namely, brain stuff. Mental states,
according to the identity theory, are more like diamonds than like
mouse traps. Functionalism is also distinguished from B. F.
Skinner's behaviorism because it accepts the reality of internal
mental states, rather than simply attributing psychological states
to the whole organism. According to behaviorism, which mental states
a creature has depends just on how it behaves (or is disposed to
behave) in response to stimuli. In contrast functionalists typically
believe that internal and psychological states can be distinguished
with a "finer grain" than behavior--that is, distinct internal or
psychological states could result in the same behaviors. So
functionalists think that it is what the internal states do that
makes them mental states, not just what is done by the creature of
which they are parts.
<end quote
This is too much fuzzy. What is a "state" when we allow any functions?
A physical state? Physical state are all known to be Turing emulable.
I think that this quote defends comp implicitly, as it uses terms like
"state" as that was a simple notion, which it is, but only with comp.
Your functionalism is just mechanism. I think, with the option of
being perhaps non digital.
Bruno
--
Stathis Papaioannou
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Stathis Papaioannou
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