[From Bill Powers (950223.1650 MST)]
Martin Taylor (950223 14:30)--
From previous discussions, I know you don't mean the following
according to an interpretation easily put upon it--solipsism. So I
hope you won't mind if I add something that I intend as
clarification, not obfuscation.
It is very difficult to make plain the difference between my view and a
belief in solipsism (which, by writing to you, I "thus deny")(To
"refute" it would be considerably more difficult). I try to give an
inkling by talking about _evidence_ that I see for existence of a
reality independent of me. That is quite different from claiming that
there _is_ a reality independent of me; I can only point to the evidence
that I find convincing, and hope that others will also find it
convincing. I can't prove that such a reality exists, and neither can
anyone else, and that's the point. I think you understand this.
The other side of the coin is that I don't need to prove that I have
experiences, or as I term them with an eye to a model, perceptions.
Everything starts with perceptions; it's impossible to deny them without
first admitting that they are there. The only question is whether these
perceptions are _about_ something that is not a perception. Proof is not
available. We can only make a working hypothesis and go on from there.
Speaking particularly of rules:
Yes, the sources are in the brain, in the same sense that the
source of the wind-blown drift of leaves is the tree, not the wind.
The wind-blown drift of leaves is also a perception, just like the rules
we deduce which explain why the leaves concentrate in some places. It's
very easy to forget the basic situation, and assume that you know that
reality contains something just like leaves, and that something we
perceive as a wind moves them, and that there are rules in nature
pertaining to the relationship between leaf-things and wind-things.
Unfortunately we can't prove that such rules exist in nature; we make
them up, we use our own perceptions to check them, and there is nowhere
else to turn for corroboration.
The environment (and if you like, the "environmental contingencies
and regularities") validates what the brain proposes.
I beg to differ. Nature does no validating of anything. We do all of
that ourselves, using our own brains and perceptions and the rules we
make up for what will constitute validation.
If the brain somehow creates a perceptual input function that
defines something in the world that is not "contingently and
regularly" affected by the body's actions, there is no control, and
reorganization is likely to alter that particular perceptual
function so that we do not see that aspect of the enviroment any
more.
You see? That is a rule you made up yourself. I'm not arguing against
it, just pointing out where it came from.
We see only those regularities our brain has defined, but we keep
seeing only those that the world supports.
So you argue. Nature doesn't offer that argument, you do. We do keep
seeing regularities, but it is no simple matter to discover whether we
would see them whether we wanted to or not. And to claim that "the world
supports" these regularities is to assume the answer to the very
questions we're asking.
Well, this is a tough one to talk about.
···
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Rick Marken (950223.1315)--
Thanks for the expert views on psychophysics. Your comment that number
scales are also "modalities" was astute -- that removes the last prop
under the idea that we can actually measure perceptions by external
means.
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Bruce Abbott (950223.1745 EST) --
Thanks for the matchup. I don't think the small differences in k are of
any import; they're probably less than interpersonal differences.
My next project will be to construct some 8192-entry disturbance tables
and an access function that will allow entering with a desired bandwidth
and getting back the next disturbance value. It's just a matter of
scaling the index to the table, and if necessary interpolating. That
will be a lot less cumbersome than handling 50 tables or so and getting
only a finite set of bandwidths. I'll distribute the tables as soon as
it's all done (to anyone who wants them).
I don't know why my posted numbers were different -- I probably changed
some little thing. Oh, I know -- I was using Xlength = Ylength to try to
get vertical and horizontal scaling the same. I think I changed it back
before sending the code to you. Anyway, I hope that was it. I don't have
a Pentium chip.
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Best to all,
Bill P.