Color
Color theory is sometimes associated with color’s
relationship to aesthetic properties. But true color theory—color
theory proper—should be devoted to
understanding the nature of colors themselves and their relationships to one
another. As far as I know, we still don’t have formalized axioms of colors as
we do for shapes.
The
Nature of Color
I suggest that the property of being a color is the property
of being a primary color or a complex of primary colors. Primary (fundamental)
colors are the building blocks for all other colors, which are known by direct
awareness. There might be exactly four primary colors
from which all other colors are made, one of which is whiteness. Primary colors
come in various degrees of saturation (or intensity) relative to other primary
colors within a complex color.
Color similarity
can be analyzed in terms of the relations that colors bear to one another
and/or to their common constituent parts. For example, blue is
more like green than yellow because green is a mix of blue and yellow colors,
whereas blue and yellow do not contain any colors in common. Various shades of
blue (from light to dark) are similar to each other to varying degrees based
upon the degrees to which they are more saturated with whiteness than each
other.
One might wonder
how many colors there are. Are there finitely many, or infinitely many? I
suspect the answer is infinitely many, and indeed uncountably infinite. The
reason is that I suspect that for any two degrees of saturation of a color,
there is a degree of saturation between of them. Perhaps I could offer the
following start to an axiomization of
colors:
(1)
For
any degrees of saturation of a color A with color B, there is a degree of
saturation of A with B that is greater.
(2)
If
color A is more saturated with color Q than is color B, and color B is more
saturated with color Q than is color C, then A is more saturated with Q than is
C.
(3)
The
color that contains all the primary colors except white, each of maximal
saturation is pure blackness [this can be supported by observation].
…
Colors
vs. Light Reflective Properties
Colors are often associated with the things that cause us to see colors—namely light
reflective properties exemplified by arrangements of
substances. A light reflective property is either a dispositional
property to reflect light at a certain wavelength, or it is a more
fundamentally a geometric (shape) property by virtue of
which an arrangement of material substances has as a disposition to reflect
light at a certain wavelength. Either way, the light-reflective property has
geometric parts, such as lines or curves (because it is a complex property
built from geometric ones). It is common among scientists to identify colors with the light
reflective properties that cause us to see colors. I believe this is a mistake.
The colors we see are not built from geometric properties. This should be no
less obvious than the fact that colors are not built from numbers, or that
shapes are not built from colors. When I focus on the redness of an apple, it
is obvious to me that the redness is not itself a complex of geometric
properties.
Now it might be replied that I’m confusing the reddish experience with the physical property of
redness. The idea is that my reddish experience is just one way of interpreting the physical property, but
the experience is not itself color. Part of this idea is right: my reddish
experience is not itself redness. However, it’s become evident to me that an
experience is itself an act of awareness (it’s more
than just a way of being appeared
to). So my reddish experience is my awareness of something, namely redness (or
a redness-shape complex that contains redness). And this redness of which I’m
aware is obviously not constructed from geometric properties. So, I say that
psychological redness is true redness, and physical redness is the reflective
property that causes me to see true
redness.
Chromatics studies both colors and the light reflective
properties that cause us to see colors.
What
things exemplify color?
If colors are not themselves light reflective properties,
then it is an open question whether things exemplify colors. In A Theory of Perception, Frank Jackson
has argued against the existence of colored things on the grounds that material
structures cause us to see colors by
virtue of their exemplifying light reflective properties and not by virtue
of their exemplifying colors. The light reflective, geometric properties do all
the explanatory work. So colors are superfluous. But if colors do no
explanatory work, then we shouldn’t believe anything exemplifies them.
Jackson’s argument is powerful, and I think it underlies the
reason why most scientists either eliminate colors or else reduce them to light reflective properties. However, there are a
couple reasons why some may find his argument to be inconclusive. First, one
might be inclined to think that things are colored even if the colors don’t
causally explain why we come to see those colors. An epistemic externalist, for
example, might say that our beliefs in colors are part of our cognitive design
or are a result of a reliable belief-forming mechanism, namely vision. Thus, it
may be legitimate to continue holding on to our naïve realism about colors as
long as we have no reason to doubt that we live in a colorful world. On the
other hand, it isn’t clear to me that we do in fact have insight into the
intrinsic nature of material objects, such that we can tell that they exemplify
some of the colors we see.
Still, there is a second reason to question Jackson’s
conclusion. It’s that if we don’t
have insight into the intrinsic nature of material objects, then we can’t be sure that geometric
properties are exemplified either. How do we know that an underlining geometric
property explains why I see a particular color? How do we know that colors
don’t play an explanatory role instead? At this point, it will be useful to
distinguish between two types of dispositional properties. One is of the form, causing x given y. The other is of the
form, being a property P, such that
whatever has P causes x given y. The latter is a second-order property—a
property of a property. The exemplification of a dispositional property of the
first sort is explained by the exemplification of a property P that exemplifies
a dispositional property of the second sort. Many different properties can play
the role P is supposed to play. So it remains open whether P is a geometric
property or a color property. Maybe the reason
light reflects off some surfaces in the way that it does is because those
surfaces exemplify a certain color and not because of their geometric
structure. This explanation may be less simple, however, than the idea that the
geometric structure does all the work.
If colors are exemplified, we can still ask what sorts of
things exemplify colors. The main candidates are these: substances,
arrangements of substances, or surfaces (as Chisholm
thought). I would guess that it’s substances and perhaps arrangements of
substances that exemplify colors. Surfaces are complexes of shapes and colors,
so they don’t exemplify colors: rather they contain them.