How the existence of color undermines the correspondence theory of truth

For the second time in recent memory, an in-depth discussion of philosophy and metaphysics has me re-visiting a book that has been extremely influential to my point of view: George Lakoff's Philosophy in the Flesh. Lakoff's thesis is a bold one: that virtually the entirety of Anglo-American analytic and postmodern philosophy are completely wrong, and not in a trivial way but in one so fundamental that philosophers ought to be completely re-thinking their approach to the 'big questions'.

The central themes in the book are:
  • The mind is inherently embodied
  • Most reasoning is subconscious, and we do not have access to it
  • The concepts we form to abstract metaphysics and other such abstractions are derived from our embodiment and cannot have meaning without it

I started re-reading the book yesterday, and one of my favorite examples comes early on in which Lakoff argues that color does not exist, but is rather a construct of the human subconsciousness interpreting the physical world. In arguing this, he shows that the correspondence theory of truth is necessarily false. In case you're unfamiliar, the Stanford Encyclopedia of Philosophy defines the CToT as follows:
Narrowly speaking, the correspondence theory of truth is the view that truth is correspondence to a fact—a view that was advocated by Russell and Moore early in the 20th century. But the label is usually applied much more broadly to any view explicitly embracing the idea that truth consists in a relation to reality, i.e., that truth is a relational property involving a characteristic relation (to be specified) to some portion of reality (to be specified).
Lakoff begins as follows:
Our experience of color is created by a combination of four factors: wavelengths of reflected light, lighting conditions, and two aspects of our bodies: (1) the three kinds of color cones in our retinas, which absorb light of long, medium, and short wavelengths, and (2) the complex neural circuitry connected to those cones.
Visible light does not have color; we are simply able to see a limited spectrum of electromagnetic wavelengths. Those waves meet millions of receptors in our eyes, and the signal is processed by our brains.

It might be tempting to stop there, but there's more to the picture. Our brains are not strictly interpreting electromagnetic radiation, but rather creating representations that are limited by the types of cones we have in our eyes and our brain's ability to process that information. In the event we are seeing an object, most of us know that light is reflected off the object; but lighting conditions vary, and yet we're able to discern objects as looking basically the same color. So even though the wavelengths being reflected off an object may vary considerably, we'll still (usually) see it as the same color because our brains know to compensate for these variances in its conceptualization of color.

Further, neither reflectiveness of objects nor electromagnetic waves alone can sufficiently describe color. Lakoff contrasts two examples: the sky, and a painting of the sky. The sky is not an object that reflects electromagnetic waves; rather, we perceive the sky as blue because of certain wavelengths that are able to penetrate our atmosphere. A painting of the sky, however, reflects light which we interpret as blue. This means that "blue" is not one thing, but something that arises from the interactions of our bodies, brains, wavelengths, and reflective properties of objects.

Another factor is what is known as "focal hues". We have, for example, a focused or central concept of "red", which corresponds with crimson, Ferrari red, blood-red, purplish-red, and what have you.  The same is true for blue, green, yellow, etc. Here's the interesting part: those focal hues correspond to areas of the highest neural response in our brains; these focal categories are purely a product of our brains, not something that is a property of the electromagnetic spectrum or the reflective properties of objects.

Lakoff continues,
Color concepts are "interactional"; they arise from the interactions of our bodies, our brains, the reflective properties of objects, and electromagnetic radiation. Colors are not objective; there is in the grass or the sky no greenness or blueness independent of retinas, color cones, neural circuitry, and brains. Nor are colors purely subjective; they are neither a figment of our imaginations nor spontaneous creations of our brains.
The philosophical consequences are immediate. Since colors are not things or substances in the world, metaphysical realism fails. The meaning of the word red cannot be just the relation between the word and something in the world (say, a collection of wavelengths of light or a surface reflectance). An adequate theory of the conceptual structure of red, including an account of why it has the structure it has (with focal red, purplish red, orangish red, and so on) cannot be constructed solely from the spectral properties of surfaces. It must make reference to color cones and neural circuitry. Since the cones and neural circuitry are embodied, the internal conceptual properties of red are correspondingly embodied.

Big implications

Since there is no color in external reality, but instead only that generated by the interactions of our bodies and brains with waves and reflective surfaces, the correspondence theory of truth – which would view color as an internal representation of an external quality, such as surface reflectance – cannot be valid. Our brains do not perceive color, but rather create and categorize color. Color, for us humans, is not a fundamental component of reality but a useful approximation of varying wavelengths of light either directly interacting with the light cones in our eyes or being reflected off of objects.

Lakoff argues that color only makes sense in what he calls "embodied realism". Color is not merely subjective, because color isn't created by our culture, but by the interaction of light cones and brains with objects and electromagnetism – it's a component of our shared biology. And it's not merely objective, because the concepts of color cannot be constructed merely by examining the surfaces of objects or the lengths of electromagnetic waves – the circuitry of our eyes and the neural pathways connecting them to our brains must also be taken into account.

This example is one of many underscoring a provocative theme: that the concepts we use to describe the world cannot be disconnected from our biology – rather, they're given meaning by our biology interacting with the world around us. This should certainly be food for thought the next time any of us wades into a conversation about metaphysics. Because the very concepts of metaphysics derive their coherence from such embodied experience, we ought to be careful about the privilege we assign to our own perspective.

This raises an interesting question: is color 'real'? If 'real' is meant to mean a fundamental quality of external reality, then no, it is not. But as an emergent construct of our embodied minds, color is as real as anything else we experience.

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