Re: What should I say to the post-grads about Godel?

On Jun 16, 1:43 am, Marshall <marshall.spi...@xxxxxxxxx> wrote:
On Jun 15, 11:05 pm, Rupert <rupertmccal...@xxxxxxxxx> wrote:





On Jun 15, 9:41 pm, Marshall <marshall.spi...@xxxxxxxxx> wrote:
On Jun 15, 9:17 pm, Rupert <rupertmccal...@xxxxxxxxx> wrote:

This seems to be a good list of references discussing the issue of
what bearing Gödel's theorem has on the question of whether the mind
is a physical mechanism.

I just don't see how anyone sensible can entertain the question of
whether or not the mind is a physical mechanism. What things
in the universe are *not* physical mechanisms? Saying that
the mind might not be a physical mechanism is tantamount to
saying that it's magic, supernatural, etc. It is medieval thinking.

Consciousness--it's all in your head.

First of all, I myself am quite friendly to the idea that the mind is
a physical mechanism and indeed that a complete description of
physical reality would be a complete description of all of reality,
and I believe Roger Penrose is also quite friendly to these
propositions (although he also thinks that a computational model of
the mind is inadequate).

What to say of Penrose? He is by all accounts quite a physicist, and
yet, does he have any background that should lend any weight to
his arguments about the nature of the mind? I am not aware of any.
Also, we have the fact that his motivation is more easily attributed
to personal aesthetic feelings than by any deep crossover from
the realm of physics. Finally, we may consider that his conclusions
are ridiculous.


Well, his arguments should be assessed on their own merits, regardless
of his background (and he has had quite notable achievements in
mathematics as well as physics). I wasn't very impressed by the
Gödelian argument; I never got around to reading the rest of the book.
I remember Solomon Feferman said that it struck him as "quixotic".
"Ridiculous" seems like a rather harsh word. I don't think that the
picture that Penrose suggests is ridiculous, just inadequately
motivated.

If the mind is not the result of computation, what is it the result
of?
There can be only two types of answer: 1) is to say that it is some
physical process that we are not yet aware of, and 2) is to say that
it is supernatural in nature. 2) is not worth refuting; we might as
well
just say consciousness comes from Santa Claus.


You can say that the mind is some sort of physical process which can
be understood by the methods of mathematical physics, and this is what
Penrose believes (though he adds that the process is not computational
in nature). You could also say that the mind is some sort of non-
physical entity (you would not necessarily have to speak of anything
"supernatural", and by the way I have to confess that I don't know
what the word "supernatural" means). You can't just say that's "not
worth refuting" and like believing in Santa Claus. It's a live
philosophical debate and there are impressive contributors on both
sides

Has it occurred to you that we don't necessarily have all that clear
an idea of what counts as a "physical phenomenon" and what doesn't?

But 1 doesn't say anything interesting either, at least as far as the
possibility of artificial consciousness goes. As the saying goes,
if consciousness can be instantiated in three pounds of fatty meat,
it can be instantiated in other implementations as well.


Yes, that may well be. But Penrose thinks the approach currently being
taken by some computer scientists is misguided because it assumes that
the mind is functionally equivalent to some sort of Turing machine.

We have the realm of Church-Turing. We have many
different approaches to computation: recursive functions, Turing
Machines, cellular automata, term rewriting, etc etc. They are
all equivalent. Almost any time we sit down to make up a
computational model, we notice two things right away: we
have to do almost nothing before we hit Turing-completeness,
and nothing anyone has ever been able to come up with gets
us past that. The most egregious example being the lambda
calculus. We have a programming language that has ... pretty
much nothing in it, just lambda abstraction of application, and
it's already computationally complete.


A computational model may or may not be adequate for explaining the
human mind.

What we see is that computational completeness is a black
hole. In designing a computational system it is almost inescapable
and always impassible. The power of this black hole will have
been just as binding on the evolution of the mind as on anything else.

A further (abbreviated) argument: what can be accomplished with
simple computation is counterintuitively impressive as the size of
the training data increases. By itself this strikes me as a complete
explanation for how well humans do relative to computers in many
cognitive tasks.

However, I would also say that I am not sure
that you can say that this proposition has been established beyond all
reasonable doubt. I will elaborate on this more below.

I say, with respect, that I don't think you especially did. You
told me some things that Godel and Unger think, but you
didn't really give any arguments for why we might think
their conclusions have merit.


That is because I myself have not read what they have to say. I have
read a sketch of what Unger says about the matter and it seemed to me
to be problematic because he seemed to be placing too much weight on
the hypothesis that we have free will. But I haven't read his book
yet, I'll have to take a look. My point was simply that these are not
mediocre minds and it is worth taking a look at what they have to say.

As I say, I am fairly well-disposed towards a purely physical ontology
but I don't think that the idea that the mind might be non-physical in
nature is totally crazy and I think if you want to form a considered
view of the matter you should look at what the best minds have had to
say on both sides.

It occurs to me that I forgot to mention Chalmers' arguments; you can
read about them here.

http://consc.net/online

In particular this one.

http://consc.net/papers/facing.html

But I guess Chalmers doesn't necessarily deny that conscious
experience may be some sort of physical process. He certain thinks
that it is amenable to scientific study.

I apologize if you would prefer it if I actually summarized someone's
argument about the matter here instead of just telling you where go
and look it up yourself. Perhaps I will go and look at one of these
writers and get back to you.

That is, unless you consider the fact that they concluded
so to be the argument.


No, that is not the argument, you are right that I did not present an
argument about the matter. I was much too lazy to bother to formulate
an argument on one side of the debate or the other, I just referred
you to literature which I thought might be of interest. Perhaps I
should not bother to comment until I have actually familiarized myself
with the debate in more detail and taken a definite stance in it.
However, at this stage I don't agree with your conclusion that no
sensible person can doubt that the mind is purely physical in nature.





We find the following quotation from the article by Feferman to which
I linked previously:

"What was Gödel's own view? Typically cautious, in the Gibbs lecture
he stated his conclusion from the second incompleteness theorem only
as a disjunction, despite his person conviction that mind is not
equivalent to a finite machine. Apparently the reason he did that is
because he did not feel he had a knock-down proof of the falsity of
the mechanist position. Rather, he put forward various arguments
against that position, including several communicated to Hao Wang and
first recounted in the latter's book, 'From Mathematics to Philosophy'
and then at greater length in 'A Logical Journey. From Gödel to
Philosophy.'"

So it would appear that Gödel believed that a computational model of
the mind is inadequate. I am not sure if he also entertained the idea
that the mind is not a physical mechanism, or that physical
determinism is false. If Jesse Hughes wants to look into Gödel's views
on these matters, the references given in the above quotation might be
a good place to start.

In any event, it seems conceivable that Gödel entertained the idea
that the mind is not a physical mechanism, and Gödel was perhaps a
sensible person. (Had a few strange ideas towards the end of his life
when he was unwell, admittedly).

There's also a chap called Peter Unger who works at New York
University who has recently come up with a book called "All the Power
in the World" where he tries to argue that the mind is not a physical
entity. Now, I understand that some people might not regard Peter
Unger as a sensible person, because he has tried in various works to
argue that no-one knows anything to be the case, that there are no
people and no composite physical objects, and that we have a moral
obligation to donate just about all of our disposable income to
organizations like Oxfam and UNICEF. Nevertheless, I find him to be an
interesting thinker and I think he occasionally comes up with
arguments that are worth considering, and, while I haven't had a
chance to look at "All the Power in the World" yet, I'm going to give
it my serious attention.

Perhaps strangely, I agree that no one knows anything, if we use
a sufficiently strict definition of "know." I also would claim that
distinct physical objects such as rocks and cars, and even people
are creations of the mind; the "truth" seems more to be that there
are only atoms in the universe, interacting. (And atoms are of
course made up of smaller particles...) However I don't find
disposing of these creations of the mind to be useful, at least
in the day-to-day, and certainly if we abandon the idea of distinct
people, we have no possible motivation to give to charity. Indeed,
the very concept of "moral obligation" disappears with the concepts
of composite physical objects; who could possibly be this so-called
"self" that is supposed to be "giving?" (God, I sounded like John
Jones there for a second.<shudder>) As I said: not so useful
day-to-day.


I should observe that Peter Unger abandoned his "mereological
nihilism" before he wrote his ethics book "Living High and Letting
Die", but I'm not sure that mereological nihilism requires us to
abandon the concept of moral obligation, or that accepting it would
remove our motivation to help poor children.

Anyway. Peter Unger has some crazy ideas and you don't have to agree
with all of them, but my point was he's a smart guy and if he thinks
he has something to say about the question of whether the mind is
ultimately physical in nature I myself am going to take the trouble to
find out more about it.

Gödel was quite a smart guy too and it might be worth finding out more
about what he had to say.

But, as you say, perhaps I should actually take the trouble to find
out what these people had to say before I start pontificating about
it.

Anyway, goodnight all.

Marshall- Hide quoted text -

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