Color: Philosophical Issues

Physicalism, Dispositionalism, and Primitivism

Our only access to the colors of things is through our visual experience. As the physicalist sees it, the red of the apple is that physical property of the apple that causes us to experience red. This would seem to be its selective reflectance of light rays across the spectrum. However, the three sensor types of the retina are limited in their ability to resolve the spectral details of the light arriving at the eye. Consequently, things with different spectral reflectances can look red. A comparable situation applies to the spectra of light-emitting objects such as LEDs. The causes of experiences of red are so physically diverse that it is not clear what or whether they have anything in common.

To secure a property that all red things have in common, dispositionalists propose that we take the redness of an object to consist in its disposition to look red to color-normal observers under normal conditions, regardless of the physical mechanisms that underlie that disposition. Unfortunately, this proposal has problems of its own. The color appearance of some objects varies significantly with variation in the spectral composition of the light source, even if the source is considered “normal.” For example, two surfaces that match in color in sunlight may look distinctly different in north daylight. In addition, the visual background and the distribution of colors in the scene will always affect the color appearance of the object to some extent, and sometimes quite dramatically. Furthermore, color-normal observers do not see colors of things in exactly the same way. So what viewing conditions and which observers shall we use to determine the “true” colors of an object? There seem to be no convincing reasons for choosing one set of conditions or observers rather than another. Once more, we are without a unitary objective feature that we could identify with redness.

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