So why red? Red is an experience we have every day, we can look around and see the color everywhere, we need no special tools to experience this phenomenon and need no special environment to have it arise. Of course all of this assumes that the person wanting to experience this is not color blind and can see fairly well, but if not one could just as easily ask about the shade of gray a color blind person links with the color red or a certain sound a blind person may hear on a regular basis. There is an old saying, Q: “What is the one thing a fish never notices?”… A: “Water”. Most of all red is something we have experienced our entire lives and have most likely taken for granted. Unlike the fish and water, red is something that has always been there but the absence/presence can be readily noticed by us even if rarely questioned. This differentiation allows for a more easily asked question.

 

So where actually is the color red? The easiest answer is to look around the room and just point to the first red object you see. But is it really what we are looking for? If you go up to the object and paint it blue is it still red? Not really, there may still be a layer red paint under the blue but we would not look at the freshly painted object and call it red. Even if we don’t paint it blue was the object intrinsically red or was it just coated with a chemical that reflected red light. If we investigated we would find no inherent redness to any of it, what we would find is a coating of a chemical compound that absorbs the wavelengths of light that we say are not red and reflected the one(s) that we say are red. So red is probably not an intrinsic aspect of an object or even of the chemistry of its outer layer.

 

What about the light that travels to our eyes, is that red? We have all seen the colors of the rainbow: Red, Orange, Yellow, Green, Blue, Indigo and Violet. Each of these kinds of light are made of different wavelengths of electromagnetic energy. When these wavelengths of light travel across the boundary of one material to another, such as air and a droplet of water in the atmosphere, they will bend in slightly different ways. These differences in the bending of the wavelengths of light will cause them to spread out, or refract, into the rainbow we see after a storm. Now let’s just look at one end of the rainbow, the red end. The red light you see, depending on how you measure it, is either made of photons that have an certain amount of energy, 2.199 electron volts, or are waves of light that have a frequency of 564nm to their wavelengths (these are the exact states of light that our eyes are best attuned to see as red). Is a specific amount of energy in a photon or a specific wavelength of light actually red? Is there inherent redness to a certain energy state of a beam of light? Many animals cannot see all the colors we can, they simply do not have the same photo receptors that we do, for them red does not exist as an experience in their realities.

 

Perhaps red is in the eye? At the back of each eyeball we have photo receptor cells. There are cones and rods. It is the cone photoreceptor cells that our eyes use to detect different wavelengths of light. Different cone cells posses different proteins which make them sensitive to different frequencies of light. The frequencies of light associated with blue, green, and red. Once a photon, or many photons, have struck these cells they will release a nerve signal that travels along the optic nerve.

 

So far we have electromagnetic energy hitting a chemical compound that absorbs some light and reflects the rest. A photon that travels across a distance to interact with a protein in a cell. Finally creating a chemical-electrical impulse that travels along a nerve fiber. None of these seemed to be a particular satisfying answer to, 'where is the color red?'

 

This only leaves one option left. Since the optic nerve travels to the visual centers of the brain and nothing before this point gives a proper answer, then a rather astonishing conclusion is left as the only remaining option; red only exists in the mind of the person experiencing it! Our brains are not only machines for reacting to input but are also devices for creating our sense of reality. This turns a lifetime of experience on its head. We each have spent our lives having this innate feeling that all reality is something external to us, that the color red is something we could point to as we moved about our day. We don’t normally contemplate how our brains are constantly creating interpretations from the input our senses give us that has proven useful but is not necessarily the truth of the ‘reality’ we are presently in.

 

Our physiology is designed to pick up and interpret useful information from the world around us. Our eyes see only a narrow band of the electromagnetic spectrum. The portion of the electromagnetic spectrum that our sun puts out, and that our atmosphere allows to pass through. Our eyes have adapted to respond to the frequencies of light that are most abundant in our environment. If our sun burned slightly hotter or cooler then the type of light given off would be different. If the composition of the atmosphere were made of different chemicals then the light that actually hit the ground would also be different. If the light that we are all awash in was different then our eyes would have adapted to gather that portion of the spectrum and not the one we now see. But there are variations within the portion of the electromagnetic spectrum that we can see and color is just the way our brains have created to quickly allow us to distinguish between these diverse wavelengths of light. The same is true for other senses as well, our ears hear the frequencies of sound that are most useful with tone being our brains short cut allowing us to easily distinguish between different wave lengths of vibrations in the air. We smell what is needed and we taste what helps us survive, with our brains interpreting singles from these various chemical detectors as sweet, sour, pleasant or unpleasant as has been useful for our ancestors survival.

 

There is nothing inherently red about a cetin wavelength of light, there is no C sharpness about a specific vibration of sound, there is nothing sweet on its own about a glucose molecule; the object or event may exists outside of our experience but the attributes our mind assigns to them exists nowhere else in the universe. Red only exists in the visual cortex of the human (and potentially some other animals’) brain.