Re: Penrose's nonsense
- From: rof@xxxxxxxxxxxx
- Date: Mon, 23 May 2005 21:00:40 +0000 (UTC)
"bjflanagan" <wordsmyth1@xxxxxxxxxxxxx> writes:
>>bjflanagan writes:
>>What if a mind/brain identity theory holds?
>>>It doesn't; the mind and experience are subjective, while the
>>brain is objective.
>>The "objective" is the result of intersubjective agreement.
>Sure; but you cannot have intersubjective agreement about certain
>things. The experience that I have when I see the colour blue,
>for example, is something that I cannot compare to the experience
>that other people have when they look at the same object.
>Flanagan
>Well, why don't you explain that to the judge the next time you run a
>red light?
What I said above does not lead to the conclusion that a person
would misinterpret traffic signals. You responded as though it
did. In fact, the misinterpretation that you displayed is so
easy to avoid, and difficult to fall into, that it leads me
to the conclusion that you deliberately pretended to have
misinterpreted me in this way, to give you the opportunity
to respond with your pugnacious comment, by which you
presumed to show your wisdom. Shame on you.
>If we both respond by saying "red" when presented with a
>novel stimulus that others agree is red, then we have all the
>intersubjective agreement we need -- a case which finds a telling
>parallel in the measuring sticks and clocks of relativity. I.e., space
>and time have subjective aspects, too, but we get around that by
>agreeing on objective standards, as is done when constructing color
>monitors and TV screens.
This more coherent response shows that you in fact understood
very well what I was saying, if not its significance. Yes, for
practical purposes we never need to compare one person's
experience of seeing a red object with another's. Whatever
experience you have when seeing red is associated with
the word "red" and with certain traffic rules in your mind,
and that allows you to avoid ending up before a judge, even
if the particular experience that you associate with the
word "red" differs from everybody else's. This is true and
I don't deny it.
However, we are not here concerned with practical purposes, because
you want to say something about the experience of seeing colours,
namely that it is "the same thing as" a certain physical process
or object. Hence the intersubjective agreement that you referred
to is to be considered not with regard to traffic lights, but
with regard to the experience of seeing colours. Now I claimed,
and you didn't deny, that there can be no intersubjective
agreement about whether what I call blue and what you call
blue are the same experience. You instead said that it didn't
matter for practical purposes. I agree that it doesn't matter
for practical purposes, but for philosophical purposes, we have to
regard the experience of seeing blue as subjective, and recognise
that physical processes and events are objective, and that
they therefore cannot be the same thing.
>R.
>For all I know, they might have the experience that I call seeing
>red when they look at it, but have always known that experience
>by the name of blue. Whether this is the case or not cannot be
>settled by studying either their behaviour or their brain.
>Flanagan
>Yes, and for all I know, you may see a meter where I see a centimeter.
>Occam's razor applies: if our brains are built along the same lines,
>and we both say "meter" when presented with a measuring stick of that
>length, then the simplest explanation is that we both see a meter.
You are invoking Occam's razor to establish the point that, if
we somehow could compare my experience of blue to yours, we
would most likely agree that they are the same. This may or
may not be true, but is irrelevant to the point I was making.
The important point is that they cannot be compared, even
in principle, and this is a property of the experience of
seeing a colour, a property which we call subjectivity,
and a property which physical processes and events lack.
>>R
>>>At best you can say that there's a correspondence
>>of some kind between them, which isn't very strong or
>>very deep.
>Flanagan
>This is an empirical issue and begs the question. How did you determine
>that mind & brain do not have the same properties?
And the answer is that we do so empirically. We notice, from
experience, that the brain is a physical object, and its
properties, as a physical object, are objective. We notice
that experiences are experienced only by the experiencer,
and are thus subjective. Then we notice that subjective is
the opposite of objective. Then we realise that the brain
and the mind cannot be the same thing.
>As Einstein, Wigner
>& Weyl all explain, the "physical" is a theoretical construct whereby
>we make sense of the regularities of "mental" experience. If the
>theoretical construct does not do justice to experience, it is the
>construct which is called into question.
Yes indeed, but the mental constructs which we build, the concepts
which we use, must, in order for us not to confuse ourselves,
remain clear and distinct, and we should not "identify" one
with another when they refer to different things. If I identify
"mind" with "brain" as you want to, then when I look underneath
somebody's skull, I would find myself saying that I see their
mind. That would not be correct. I agree with Wigner and Einstein
about the status of the physical and its relation to the
mental, and I recognize that an immediate consequence of this
is that we cannot "identify" the "mental" experience with
the physical, because that would be to "identify" mental
experience with a theoretical construct which arises in
experience as a tool to characterize regularities of that
experience. Nobody should confuse their thoughts with the
things that they are thinking about.
>>>Here is what Chalmers, a philosopher, wrote in Sci Am:
>>>"The abstract notion of information, as put forward by Claude E.
>>>Shannon of MIT, is that a of a set of separate states with a basic
>>>structure of similarities and differences between them."
...
>R
>Both Chalmers and I were referring to Shannon's introduction
>of the notion of information. Chalmers gave an inaccurate
>description of what Shannon said.
>Flanagan
>I suggest you revisit what Shannon wrote:
>cm.bell-labs.com/cm/ms/what/shannonday/shannon1948.pdf
I did, just before I declared that Chalmers had misrepresented him.
If there's a section that I missed in that paper where Shannon
mentions an "information state", or "a set of separate states with
a basic structure of similarities and differences between them",
then I'd be grateful if you could point it out to me.
>R
>Now, once again I'd like to draw your attention to the distinction
>between the experience of seeing a colour, and the wave associated
>with coloured light. Only the latter satisfies the rules of vector
>addition.
>Flanagan
>Well, you're simply mistaken. Red at 620nm added to green at 540 nm is
>indistinguishable from yellow at 580 nm. On the vector model I sketched
>in, there is a precise correspondence between what is experienced and
>what the model predicts.
I find it difficult to believe that you still don't understand what
I've been saying. The addition of red light to green light is a
mixture of light, achieved by shining the red and the green light
into the same region of space. It is not an addition of the experiences
of red and green. The experience that I have when viewing this
mixture may be indistinguishable from the experience that I have
when I see monochromatic yellow light, indicating that the two types
of light (mixed red/green light and yellow light) have the same
effect on my sensory apparatus, but that does not mean that any
addition of experiences has taken place, which is what you are
trying to suggest.
>R
>It's a pity that you didn't reply to my objections to your theory
>that the experience of seeing colour is identical to a quantum
>field:
>Flanagan
>It's a pity you don't think instead of simply regurgitating the
>received wisdom.
But that is little more than an insult. Shame on you again.
>>> 1. When mixing quantum states, there is a very important
>>> phase to be taken into account: |up> + |down> is very
>>> different from |up> - |down>. When adding colours there
>>> is no corresponding phase.
>Flanagan
>Photons of the same color (tone) but 180 degrees out of phase cancel.
>So how is there no corresponding phase?
My apologies for not being clearer. You are talking about addition
of experiences, claiming that the experience of seeing one colour
can be added to the experience of seeing another colour, and you
do this because you want to identify the experience of seeing
colour with a quantum state. Because of this, when I said
"When adding colours there is no corresponding phase", I was
using "colour" to refer to the experience of seeing colour. Your
statement that "Photons of the same color (tone) but 180 degrees
out of phase cancel" clearly refers not to the experience of
seeing colour, but to the addition of waves to waves. It is
not news that waves can be added together.
>R
>>> 2. ... What you want to do is say that the experience of
>>> seeing colours is the same as a quantum state, based
>>> on a shared additive property, but the fact is that it
>>> is not the experiences of seeing colours which
>>> can be added together; only the lights and inks
>>> are added.
>Flanagan
>O, so there is no corresponding perception?
There is the experience of seeing red and the experience of
seeing green. There is the experience of seeing yellow, which
can be induced by mixing red light to green light, or red
ink and green ink. This is not the addition of the experience
of seeing red with the experience of seeing green. You can
say that the perception of yellow "corresponds" to the mixed
light if you like, but there is no corresponding "addition"
of perceptions.
>R
>A set of such linear operators which is
>indexed by a continuous variable is called a quantum
>field. This is a purely mathematical object. You
>might say that there is something physical which
>corresponds to the mathematical object. Maybe, but
>it is the mathematical object which is "quantum".
>Flanagan
>You may wish to apprise the larger community of physicists of your
>discovery, most of whom believe that the universe is quantum and that
>the formalism has been developed to reflect this understanding.
More sarcasm. Shame on you again.
>And now I really have to get back to work. Good bye.
Good bye.
R.
.
- References:
- Books to read for intuition rather than precision.
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- Re: Penrose's nonsense
- From: bjflanagan
- Books to read for intuition rather than precision.
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