The human eye can see millions of colors, but are there colors that exist outside of the visible spectrum that we cannot even imagine? This is a fascinating philosophical and scientific question that has been pondered for centuries. In this article, we will explore the science of color perception, the limitations of our visual systems, and thought experiments about imagining impossible colors.
The Science of Color Perception
To understand if we can imagine new colors, we first need to understand how we perceive color in the first place. Our eyes contain photoreceptor cells called cones that are sensitive to different wavelengths of light. There are three types of cones:
- S cones – sensitive to short wavelengths (blue light)
- M cones – sensitive to medium wavelengths (green light)
- L cones – sensitive to long wavelengths (red light)
These cone cells have peak sensitivities to red, green and blue light. By combining signals from all three types of cones, the brain can perceive the entire spectrum of visible light colors. So any color we see is a combination of these three primary colors. This is known as the trichromatic theory of color vision.
The visible spectrum that humans can see ranges from about 380 nanometers (violet) to 740 nanometers (red). Some animals, like bees, can see ultraviolet light, while others, like snakes, can detect infrared. But generally, the human visual system can only see a small window into the full electromagnetic spectrum.
The Limitations of Human Color Perception
Given the biology of our visual system, there are some clear limitations on what colors we can perceive:
- We can only see three primary colors of light (red, blue, green)
- We cannot see light outside the visible light spectrum
- We cannot imagine or describe colors that do not stimulate our cone cells
No matter what variations or combinations of colors we are exposed to, they ultimately trigger one or more of our cone cell types. This leads to an interesting philosophical question – can we imagine colors beyond our biological capabilities?
Thought Experiments on Impossible Colors
Over the centuries, many thinkers have come up with thought experiments asking humans to imagine colors outside what we can see. Here are some famous examples:
Mary’s Room
The Mary’s room thought experiment, proposed by philosopher Frank Jackson, imagines a woman named Mary who lives in a black and white room and sees the outside world only through black and white TV monitors. Mary knows everything there is to know about color and color perception. But when she steps outside the room and sees a red rose for the first time, does she learn something new about color experiences?
This raises the question – can we ever truly imagine qualia (first-hand experiences) that we have never sensed? Can knowledge about color alone let us imagine them?
Impossible Colors
Some thought experiments invite us to try to imagine colors that do not fit within the constraints of our visual systems. For example, reddish-green or bluish-yellow. We can imagine reddish-orange and blueish-green, but our brains cannot conjure the experience of reddish-green.
There are also imaginary colors described in sci-fi books, like octarine, that readers try to picture even though they have no physical correlate. These thought experiments suggest we cannot visualize colors that our brains and eyes cannot process.
Extra Color Channels
What if we had 4 cones sensitive to 4 primary colors instead of 3? Or even more? It’s possible there are variations in cone cells between individuals, but in general humans have red, blue and green channels. We cannot describe or imagine what having extra color channels might be like.
Some animals like mantis shrimp have 12 color receptors. They likely perceive a spectacular world of color combinations forever beyond our imagination.
Studies on Imagining Impossible Colors
There has been some neuroscience research directly probing our ability to imagine colors outside our visual range. In one study, subjects were asked to imagine colors that are real combinations of blue and yellow light. They were also asked to imagine fake “forbidden colors” like reddish-green and bluish-yellow.
Functional MRI scans of their brains showed similar color perception areas lighting up when imagining real and fake colors. But the fake colors triggered conflict between blue-yellow and red-green neural pathways. This suggests we can picture impossible colors, but our brain hits a wall when processing them.
Does Synesthesia Allow New Color Experiences?
Synesthesia is a blending of the senses, where input to one sense triggers experiences in another. In chromesthesia, hearing sounds triggers experiences of color. Some theorize this allows synesthetes to experience colors beyond the normal visual range.
But studies show synesthetes mainly see colors from the normal visual spectrum, just in association with sounds. Still, there may be rare individuals who can somehow visualize colors outside our normal range.
Color Spaces Beyond RGB
While humans are limited to RGB color, there are other color spaces with dimensions we cannot perceive. Graphics programs use color pickers with CMYK (cyan, magenta, yellow, black) or HSV (hue, saturation, value) to represent a broader range of colors. But these still rely on mixing RGB colors.
Mathematically, some models like CIELAB were designed to represent all possible colors the human eye can see. But even these exist within the confines of our biological vision.
Conclusions
Overall, the evidence suggests that because of the limitations of our visual systems, we cannot imagine or experience colors outside the visible light spectrum. All the colors we can describe or think of are combinations of red, green and blue light. Even thought experiments or neurological conditions like synesthesia do not appear to give insights into colors beyond our capabilities.
While we can conceptually think about “impossible” colors, our brains cannot truly visualize or process them in a meaningful way. However, it remains fascinating to ponder how other animals with different color perceptions or theoretical beings with expanded senses might experience amazing new dimensions of color we cannot.
Our imagination can take us to the limits of our color perception, but likely not beyond. However, exploring these boundaries gives us appreciation for the incredible capabilities of the human brain and our unique, if limited, window into the phenomena of color.
