[From Bill Powers (931019.1100 MDT)]
Martin Taylor (931018.1700) --
I don't know, but it seems to me that we are getting more and
more confused over "contrast" "phonemes" "words" "morphemes"
"phonetics" and the like.
Very nice summing up, but you left something out: LAP, or
language as process.
Your analysis focuses primarily on language as an emergent
external-view phenomenon (language as artifact) and language as
evidence of high-level control (language in use). I agree to both
of these distinctions. But, for language in use, saying THAT we
interact with others and mutually reorganize or WHY we do so does
not answer the question of HOW we do this or WHAT organization in
each individual is the result of all this.
The question of HOW is what concerns me as a modeler. The
appearances of language as artifact are seen without the
discipline of a model; there is no constraint that makes the
description correspond with a description of an underlying model.
Thus the objections that Rick and I have had to a statement that
people perceive contrasts. When you ask HOW you would build a
perceptual function that would perceive contrasts between words,
you find that you have to make complicated assumptions. Even when
you do make such assumptions, the result is not perception of
contrast per se, as a dimension of experience, but an effect on
perceptions which are not themselves contrasts, but phonemes (or
whatever). Contrast is an outcome of these effects, not their
explanation.
If you truly built a contrast-perceiver, it would report its
world in terms of a degree of contrast: 6 units of contrast, 25
units of contrast, 0 units of contrast. That's all the signal
would indicate: contrast. It would not, could not, also indicate
contrast of WHAT with WHAT. Any two words that differed by 6
units of contrast would be perceived as the same contrast: 6
units. The contrast-perceiver could not tell which words the
contrast occurred between, or what features of the words account
for the sense of contrast-ness. This is entirely appropriate for
a high-level perception; the details are lost, or rather the
details remain at the lower levels that handle details.
This problem keeps recurring in our linguistics discussions, as
well as others. I've described it as the difference between
CHARACTERIZING a model and DESCRIBING the model. When you
characterize something, you say something about what the model
accomplishes, or offer a metaphor for its behavior, or give some
other general assessment of the model that FAILS TO MENTION WHAT
THE MODEL ITSELF IS. So you can say that the stretch reflex is a
system that corrects errors, or that makes its input match its
reference level, or that is purposive in some regard --
statements which may be true, but which leave us in ignorance of
what the stretch reflex IS in terms of functions and signals in
the neuro-muscular system.
So it is with a concept like contrast. To say that phonemes are
identified by their contrast with other phonemes really just
characterizes the recognition process in a metaphorical way. It
is as though something were looking at the difference between
phonemes and using this difference as the basis for
identification. That may be an entirely reasonable metaphor, but
it takes us no closer to being able to say how phonemes are
distinguished.
In fact, it begs the very question that we try to answer by
modeling: what it is that detects a difference between two
phonemes so that a judgment of contrast or no contrast can be
made? Before any difference can be noted, there must BE a
difference -- that is, the individual phonemes (or whatever the
units are) must be represented differently, individually. If
their representations are identical, there is no magical way that
a difference between them can be detected.
When we understand how these differences are generated, we will
be able to solve the apparent paradox of identical perceptions
being treated differently and different perceptions being treated
identically. We will see that if there is a different treatment,
there is an actual difference, and if there is no different
treatment there is no actual difference. We will find that the
paradox existed only because we were assuming an inadequate model
of how the perceptions in question work. Perhaps in defining a
phoneme we have unwittingly created the paradox. In that case we
have to find a more useful unit of organization that doesn't lead
to mysteries. Perhaps the truth is that the basic unit of
recognition is not a single phoneme, but a space-time pattern of
phonemes. That's the assumption I've been using. With a space-
time pattern, there's no need for any concept of contrast as a
causal entity. The OUTCOME of perceptual processes based on such
patterns may well be a judgment of contrast, but contrast is not
the basis for the judgment.
Well, I'm probably still butting my head against the same stone
wall.
ยทยทยท
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Best,
Bill P.