Colors Are Not Real, But Only in Our Heads

Each day our minds are bathed by countless colors in the world, from the deep red of a rose to the verdant green of the countryside, and everything in between. Although we revel in the multitude of colors that surround us and reach out to us, science — as far back as Galileo — tells us that these colors exist only in our heads.

As part of an ongoing discussion in the New York Times Book Review, philosopher, psychologist, and robotics engineer Riccardo Manzotti and author and professor Tim Parks discuss what this means for the nature of consciousness and how we perceive reality.

Manzotti provides the textbook view of what we call color. It goes something like this: objects reflect a subset of the sunlight that strikes them. When we view an object, the reflected light enters our retina and stimulates the cones. The cones react to different wavelengths of light — short, medium or long-range — and create signals that are merged in the retina and sent through the optical nerve to the cortical areas of the brain. Nowhere in this description does Manzotti use the term “color.” Science would probably agree with the absence of that term.

Starting in the nineteenth century, scientists examined the retina and optic nerve, but found no sign of anything resembling color. Later, in the 1970s, one neuroscientist suggested that color perception resulted from part of the visual cortex in the occipital lobe called V4. However, other neurons and parts of the brain may also be involved, so this is far from the end of the debate.

If science were the only tool we had for investigating the universe, we probably would have no concept of color at all. Reality — as scientists like biologist Gerald Edelman suggest — would be colorless. Still, when we look at a rose, we see its color. And when we look at a rainbow, we see many colors. Manzotti says that our experience of color — and the entire world — could be described as a kind of hallucination.

Colors a Product of Our Brains

Neuroscientist David Eagleman puts it like this: “Our perception of reality has less to do with what’s happening out there, and more to do with what’s happening inside our brain.”

The other problem with our experience of color is that the same object can be perceived as a different color depending upon the light shining on it and other factors. In one illusion created by biologist and psychologist Akiyoshi Kitaoka, two spirals appear to be green and blue, but are actually identical. This is created by different color stripes crossing those same-colored spirals.

So our perception of color is much more fluid than science’s understanding of the factors in the environment that give rise to those colors. Scientists might say that this means we are hopelessly ignorant of the true nature of reality. As Plato said, we are staring at shadows on the wall of a cave while true reality is beyond our reach.

Manzotti suggests that in order to come closer to understanding our perception of color we need to “bring our consciousness back in the picture.” A neuroscience view of consciousness, though, is not much clearer than its understanding of color — there is no thing in the brain that can be identified as consciousness, just like there is no “color unit” either.

Manzotti said that bridging this gap between what science knows about color and our experience of it — both individual and collective — might require us to move “beyond the idea that consciousness is a ‘representation’ of the world at all.” So our perception of color is not really about what is “out there,” but instead about our inner experience.