From: Matt Gingell (mjg223@is7.nyu.edu)
Date: Tue Oct 26 1999 - 23:19:27 MDT
>> The assertion that qualia are not computable is totally meaningless.
>> Compare against the assertion that baseballs are non-computable or
>> that qualia are NP-complete. Do you have any idea what you're talking about?
>
> Yes, I do. Baseballs are non-computable, although the *important* part
> of their behavior is easily computable. Baseballs are quantum-random,
> but not visibly. NP-completeness is a predicate that describes
> problems, not algorithms, so it can't apply to qualia.
Ok, I've taken a deep breath. Let's try again.
Computability refers to functions - mappings from one set onto
another, mappings from input tapes to halted tapes - not baseballs,
qualia, or any other non-abstract phenomenon. The problem I have is
that you're extending the concept to another domain without being
clear what you're talking about, then refusing to explain when
queried.
It's unclear what you mean when you refer to the computability of
qualia. Do you mean that there is no algorithmic mapping from a symbolic
description of the objective universe to a description of subjective
experience? Do you mean, as you seem to have implied, that qualia can
not exist in a universe who's behavior can be modeled completely by a
Turing-computable formal system? Do you mean that qualia have
properties and behaviors of their own which can not be described
rigorously. Are you saying that a purely computation model of the mind
can not account for the existence of qualia? Or do you believe, as you
seem to have implied, that Turing/Church is simply incorrect and there
exists some more powerful scheme for an abstract computer?
These aren't rhetorical question - I don't know what you mean - and
given your refusal to elaborate further the statement is meaningless.
I'm interested if you have anything to say on any of these topics, but
I'm not going to interpolate between isolated pearls of obfuscated
wisdom. If you don't want to go into it then we can let it drop.
Anyway, I apologize for the tone of my previous message - I'm not
interested in getting into a pissing contest with you - but perhaps
you can compute from whence my subjective experience of irritation
arose.
> I might point also point out that truly random processes, strictly
> speaking, require a minor extension of Turing computability; it's just
> that the qualitative behavior of a random process can be simulated by
> pseudo-random processes (or, for finite processes, hidden variables in
> the initial state). The assertion that baseballs are non-computable is
> not only meaningful, it is trivially true. Frankly, your assertion that
> the noncomputability of a process is "meaningless" is so odd that I'm
> starting to question your own understanding of Turing computability.
Yes - Turing machines are totally deterministic. I'm not sure if
adding a random number generator extends the set of problems you can
solve vs. an arbitrarily good distribution of pseudo-random numbers.
It seems like it should, but I can't think of a concrete example off
the top of my head.
The baseball example, as is clear from above, wasn't referring to
behavior. It was an analogy. Baseballs aren't computable - that
statement has no meaning. Their weight may be computable, their color
under different levels of illumination may be computable, their wind
resistance at a certain velocity may be computable, and so forth.
Until you specify want you want to talk about, computability is
inapplicable.
But I don't think the behavior is necessarily uncomputable. In the
absence of an observer, quantum physics can predict it's behavior
perfectly. It's only when we step in and collapse the wave function
that there's any uncertainty. It becomes an issue of frame of
reference.
You can certainly come up with other problems where a result is
computable only in some frames of reference, there's no need to assume
a non-deterministic universe. (or get into wacky quantum philosophy
stuff.)
>> If you don't want to go into it then provide a direct reference.
>
> No.
Ok. <looks down, checks a box on funding request form.>
>> The above is just juvenile.
>
> Nyah nyah.
Oh dear lord... 'I know you are but what am I' flashback.
I'm reminded of the time I Godelized my little brother's Duplo AI and
he disassembled all my Halloween candy in retaliation.
-matt
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