[hist-analytic] The "Analytic A Posteriori"
aune at philos.umass.edu
Thu Sep 3 07:44:14 EDT 2009
OK, Danny, one more response on the color issue. Again, I say that
your alleged counterexamples are not inconsistent with what I say.
The most they show is that we may be wrong in thinking that we are
dealing with the very same color. But I never doubted this or implied
that it is any way doubtful.
1. The spreading effect. If we mask the adjoining colors of the red
strip with a neutral color, we can see that the red strip is uniformly
the same. We can discern no difference. (Of course, of course, we
could make an error here; errors are always possible.) If we remove
the masking material, the part of the strip adjoining the black line
looks darker. We know the color did not actually change. We know we
are dealing with an illusion. (Who doubts this?) The spreading
effect is presented as an illusion.
Optimal conditions are conditions in which things (in this case
colors) look the way they really are to people with optimal vision,
i.e. who have the visual capacity to discern the colors things
actually have in optimal conditions. Don't tell me there is a
circularity here. Our conceptions of optimal perceptual conditions
and optimal perceptual capacities are closely interrelated. As time
goes by we learn more and more about both kinds of optimality. We
learn to recognize more and more conditions (such as the spreading
effect) that produce deceptive appearances. We also learn more and
more about optimal perceptual abilities. We learn to devise tests by
which to identify perceptual abnormalities. None of this shows my
principle to be false.
2. Transitivity/intransitivity. Suppose we can discern no difference
in color between a and b and b and c but we can discern a difference
between a and c. What do we conclude? Assuming we are dealing with
perceivers with keen vision, we will conclude that either (i) the
three things are not being perceived in equally optimal conditions, or
(b) there is some difference in the colors of a, b, and c that we are
not discerning in these conditions. So, if the matter is important,
we continue to investigate the objects and the conditions. Do we
conclude the principle I gave is false? NO. We have indirectly
discerned a difference that exists either in the relevant perceptual
conditions or in one of the perceived colors. We haven't located that
difference, but we know it exists.
3. Your third case: "whatever conditions we specify as optimal, it
is possible we can find other (even better) conditions under which we
can distinguish between shades which were indiscernible under the
(old) optimal conditions." Yes, this is possible. Errors are always
possible. But this doesn't mean the principle is false. You say "What
we can discern depends upon our limited powers, so an enhancement of
these powers would produce such a change of conditions.." Yes, our
powers can in principle be enhanced, and we can continue to learn
about external conditions that can effect what we perceive. But none
of this shows that the principle is false.
Yes, yes, yes, mistakes are always possible. But whoever doubted this?
I will comment on other things you say abut analyticity in another
installment. But please, no more about the color case. I can imagine
further things you might say, but let's leave the matter here. Other
readers can judge the matter on the basis of what we have already said.
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