John K Clark (
Wed, 11 Feb 1998 21:38:52 -0800 (PST)


On Tue, 10 Feb 1998 Brent Allsop <> Wrote:

>Something physically real and objectively (or abstractly) observable
>is going on in our brain that is producing conscious sensations or

I agree that something physical must be causing qualia, but we can never know
what it is with any certainty unless we assume there is a direct connection
between qualia and behavior.

>We simply must figure out how and why this is.

I'm not saying we can't come up with theories of conscienceless, we can come
up with lots of them, I'm saying that without behavior there is no reason to
pick one over the other because there are no facts they must explain, all are
equally good, or bad.

>Someone will say, I'm going to manipulate/stimulate a part of your
>brain in such a way that it will produce precisely the sensation
>I experience or use to represent salt in your mind.

And when you do I will make a sound with my mouth like this:

"I hear the sounds you just made with your mouth and it is causing me to
make the following sounds with my own mouth:"

I do feel a sensation, I've felt it before and called it "salty". You have
shown me detailed measurements of your brain when you claim you are also
experiencing a salty sensation, and I have compared them to measurements
of my own brain. I see a vast number, an astronomical number, of
differences in the measurements of our two brains, however because we're
both making the same noise with our mouth (this is salty) there must be
something similar in the two measurements. You have found them and proven
conclusively that these small brain similarities in a huge sea of
differences are the reasons we made the same sounds with our mouths. I
have no problem with any of this, HOWEVER you then make a huge unwarranted
leap of logic that this has something to do with consciousness. Just
because you and I make similar sounds is no reason to think that your
subjective experience is anything like mine, or even that you have any
subjective experience at all, UNLESS I assume that qualia and behavior
are inextricably linked. I have made that assumption, you have not.
If as you think, one part of the brain produces intelligent behavior and
a completely different part produces qualia, then all you've explained is
the intelligent part, the qualia might be made somewhere else in all
those enormous differences between you and me.

>The experiencer might respond with, that's not what salt tastes like
>to me. You would be able to verify that this person isn't lying, and
>that he uses a different sensation to represent salt because you
>will be able to objectively observe the physical phenomenon that is
>producing his sensation and see that it is different.

You're saying that if you already have a theory of consciousness that you
know for sure is correct (!) then you could know for sure what somebody else
is feeling. There are two problems.

1) The theory you came up with can never be better than the evidence, and the
evidence can only come from behavior.

2) Even if I knew that at the present moment you at 88.4762 on the happiness
scale, 23.2211 on the fear scale, and 11.0216 on the pain scale, I still
wouldn't know what it's like to be you, even reading a poem by a great
poet can't do that. At best all I could know is how I would feel if I were
in your situation, not how you feel in your situation.

>Are you saying that abstractly representing 700 nm light with an
>array of transistors in a particular state could reproduce the same
>phenomenally glorious "red" qualia your consciousness use to
>represent 700 nm light?

Yes, that's exactly what I'm saying. It's not obvious to me that an array of
transistors in inherently less glorious than a glob of gray goo.

>In order to represent any abstract information, there must be some
>physically real phenomenon that can reliably assume various different
>distinguishable states.

Correct. Shakespeare can be represented as ink on paper or magnetic spots on
a disk or charged capacitors in a RAM chip or neuron connections in a brain,
it doesn't matter, the meaning is the same, it's still Shakespeare.

>Though certain physical phenomenon can model different physical
>phenomenon, they will never be precisely, fundamentally, like each

If so then how could I ever know for sure what it's like to be you?

>You are as smart as I am. But if you use a drastically different
>sensation to represent a salty taste than I do, this matters.

I can say with complete confidence that the way your brain represents a salty
sensation is different than the way my brain does, because we're different
people with different brains. However, if neither of us likes a lot of salt
in our drinking water and both of us like a little salt on our popcorn then
that is evidence (I admit not proof) that the two subjective sensations may
be similar

>A purely abstract machine can achieve the same ability to be aware
>of salt. But again, the fact that there is no real subjective salty
>that is representing salt

I have 4 questions:

1) Why is a person less abstract than a machine?
2) How do you know the machine is not experiencing a salty taste?
3) How do you know that I am?
4) Most important of all, why oh why did random mutation ever come up with
things that have subjective experience if it is not linked to behavior?

>People think that red is something out beyond our eyes, some quality
>of light or something.

I think you're attacking a straw man, nobody in the AI field, or anybody who
has spent any time thinking about philosophy would believe such a foolish

John K Clark

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