[Fis] Consilience and Structure

Dear FIS discussants,

There has always been a puzzle about why the mathematics has an ever
widening role in science. Mathematics introduces strange abstract entities
into our representation of nature: numbers, manifolds, groups, variables,
operators and so on. Yet few believe that such abstract entities literally
exist in nature. A more plausible explanation is that mathematics provides
a precise way of representing the STRUCTURE of the world. It helps us see
how things relate to each, not what things are in and of themselves. Taking
this line of argument to an extreme, one might claim that if the consilience
of scientific inductions, tools, models, communities is about the
relationship of different things to each other, then consilience is the
basis of all our knowledge.

Perception is a source of knowledge, so it provides a test of this thesis.
On the surface, it seems to pass this test because our perceptual judgments
of the world are based the consilience of a wealth of information coming
from quite separate modalities--vision, hearing, touch, smell, and
kinesthetic information.

Even our detailed understanding of how visual perception works seems to
provide a striking confirmation of this idea. An old controversy about
color vision was about whether color is a primary (objective) property of
things in the world or a secondary (subjective) property. The simple-minded
theory of color perception says that it consists merely in the detection of
the wavelength of light striking our retina. This might have supported the
view of color as a primary quality if it were true. But it was Land's
experiment in the middle of last century that blew this particular myth out
of the water.

Land produced three black-and-white photographic transparencies of a
colorful scene with a camera--one with a filter that blocked all light
except red light, one with a filter that blocked all light except yellow
light, and one with a filter that blocked all light except blue light. It
is no surprise that we see the scene in full color when we reverse the
process by projecting red, yellow and blue light simultaneously through the
transperencies onto a screen. This is because the retina contains three
kinds of color sensitive receptors called cones, one most sensitive to red
light, one most sensitive to yellow light, and one most sensitive to blue
light. But what happens if we replace the red, yellow and blue light with
narrow band of yellow light shifted slightly towards red end of the
spectrum, a narrow band of yellow light in the middle, and a narrow band of
yellow light shifted slightly towards the blue end of the spectrum? To
everyone's surprise, Land demonstrated that we see the scene in full color
(albeit slightly washed out) even though there is only yellow light striking
our retina. Color pereception therefore involves the detection of
DIFFERENCES in light frequencies, and not light frequencies per se. Color
perception rests on the detection of relational facts.

But should we therefore conclude that color is therefore a relational
property of the objects in the world? One might object that this would be
to confuse what we know with how we know. The 'how' involves the detection
of relational facts, but the conclusion (the inductive proposition) drawn
from these facts is about the intrinsic nature of things in the world. For
example, we all know that we can only measure mass RATIOS, but nobody seems
to conclude from this that mass is therefore a relational property of
things.

Whose right? If you have a solution, then please let me know.

Malcolm

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Received on Mon Nov 8 07:27:54 2004