You don’t see with your eyes, you see with your mind.
Perhaps this is a trivial distinction but understanding it can open up our perspective. The hard truth is that the physical world is not full of colors and objects; it is full of, what Richard Feynman referred to as, a chaotic sea of electromagnetic waves bouncing off in every direction. These waves inevitably find their way to our eyes. From there, light detecting cells within our eye cells are excited sending electrical signals into our visual cortex. The range of the electromagnetic spectrum that we can see is referred to as the “visible spectrum” and it about about 0.0035% of the spectrum as a whole.
Doesn’t really seem like we are seeing the whole picture does it?
Nevertheless; this is how we experience the chaotic sea of electromagnetism; through the lens of our mind. Colors, for example, are just tags in our mental map to give us more information about the world. For a long time in our evolutionary past, sight was limited to shades of gray. This is a side effect of only being able to detect one wavelength of light. We still have these types of light receptor cells in our eyes which are highly effective in low intensity light, you might know them as rods. Every time you stumble out of bed in the grey haze of darkness, these cells help you avoid stepping on your dog or running into a wall.
Fortunately, the human eye has also developed cells responsible for color distinction, known as the cones, and the human eye has 3 of them. Our minds call these varying wavelengths red, green, and blue, but what they really are is differing wavelengths of the electromagnetic spectrum (blue being the shortest and red being the longest). With these differing wavelengths, our minds are able to differentiate between varying objects in the world. Most evolutionary scientists believe this was a trait evolved to be able to detect fruit out of the trees or predators stealthily approaching. We may feel privileged to have 3 different receptors of light for color but we are far from the top of the animal kingdom’s light detectors. Dogs may only have two, but the bullet shrimp has 12 different color receptors allowing them to see colors we could never even imagine. Although, all colors are really just a part of our imagination.
It is thought that the receptor for blue light was the last to evolve in humans. Contrary to many other evolutionary theories, this theory is actually supported by historical texts. It is not very often that a species records their own evolutionary past in writing but humans are an exception. Many ancient texts lack any mention of blue and describe colors in a very strange manor. Homer’s Iliad and Odyssey may be the best example of this strange color description as it refers to honey as green and iron as purple, but has no mention of blue. In fact, it was not until around 4,500 years ago that blue was first described in writing. More studies have sought after isolated tribal communities and found that their ability to detect blue is quite limited.
This result is further validated in studies of children when asked what color the sky or the ocean is on a given day. A adult may say blue to both. But a child, who is unbiased with preconceived notions, often refers to the ocean as green or the sky as white or grey. This may be more a fluctuation of language and psychology than biology, but it gives us insight into the nature of color and sight itself. In nature, blue is most frequently a background color. One of the colors whose detection is rarely beneficial for avoiding predators or hunting prey. Spotting the colorful bird out of the sky or the dark shark out of the ocean may keep you alive but the color blue is more the canvass than the painting. But somewhere along the road we found it valuable to even detect the varying blues of the background, perhaps due to ever adapting camouflage of predator and prey; the arms race of the natural world.
Recently a controversial picture made waves across the internet. It is a image of a dress that can be seen to have different colors depending on how the mind conceives the shadow. This “shadow” type of optical illusion is just one of many different types of optical illusions that can be found in any book on the subject. These are referred to by Dr. Neil DeGrasse Tyson as “brain failures”. Which is a more accurate definition, but the deeper truth is that the mind is not meant to see the world as it truly “is,” but instead, the mind developed to keep us alive and reproducing. Sight keeps you from falling off a cliff on your way to find a mate. These optical illusions once again expose this distinction between the external and internal “world.” For it is truly our minds that build our internal world, and this world is the only one we have ever known.
The problem is computing power. Our minds have a limited ability to process information, and so, they often take shortcuts. We assume that objects in the shade of an image are actually lighter than they appear, we assume that parallel lines grow closer as they approach the horizon, and we assume that adjacent edges are joined. These are all general rules that almost always work in 3D, but, on paper, these optical illusions point out our minds flaws to spot the exceptions to the rules.
Still believe that you see with your eyes? Enter Daniel Kish, who may seem like a normal man making some strange noises while he rides his bike down the street; however, Daniel has no eyes. Cancer had crippled his eyesight and after only 13 months of his young life, and so he had them surgically removed. Unwavered, Daniel has tapped into a form of sight that has only been used by a few species other than homo sapiens, such as bats and dolphins. We know this method of vision as echolocation. Those strange noises he makes as he rides his bike are actually precise tongue clicks that bounce off the objects in his environment and return to his ears unveiling a depth of information. Using MRI imaging, the brain of Daniel and many others that employ this clicking echolocation has shown activity in the visual cortex. These people may detect sound waves instead of light, but even the renowned biologist, Richard Dawkins, has postulated that the brains of echolocating species would still use colors as mental tags. It then follows that the mind would use the mental device known as color to convey data to Daniel. As strange it may seem, we no longer need to explain color to a blind person; although, the meaning behind these colors would be different. The mind has simply rewired its inputs to form an 3D image of the world from the available information. Reminding us that we too are forming a world in our minds everyday; a product of the preoccupying illusion we so often regard as reality.
The entire universe might as well be squeezed between your ears; every burning star and every spinning galaxy, because there is no experience beyond the filter of your mind. And there is no scientific way to prove a world beyond our personal microcosms. In one blink you existed, and from then on out you have known nothing but what it is to be you.
Some argue that our ability to understand that others are also conscious and having internal dialogue of their own is what separates us socially from the rest of the animal kingdom. Although, is this belief that others are also conscious worth testing?
In philosophy, there is a term called a philosophical zombie. These zombies are hypothetical biological machines that walk through the world and are indistinguishable from the rest of humanity. They say all the right things to mimic consciousness; essentially, exactly how a computer intelligence might operate. But if we take a strict physical interpretation of reality, all we are are biological machines ourselves, perhaps programed by evolution to just give the right answers to display consciousness, even to ourselves. But inside our own minds we feel something more, something immaterial. And our guts tell us our peers share this feeling.
We unconsciously accept the improvable hypothesis that others are, in fact, conscious. And perhaps we must. Most of the most terrifying psychological disorders are ones that disassociate people from consciousness. If we do not see others as also conscious, we become cold and utilitarian. If there is a evolutionary reason for the shared belief in consciousness; perhaps, it is for empathy.
Maybe we just made up consciousness so that we don’t all kill each other. Or maybe there is something to it. Whatever it is, scientifically we believe it to arise from the complexity of a human mind. For the mind is how we experience all of the world. We may believe that the world exists out there beyond our minds and we are simply moving through a physical reality just like the one in our heads. We may believe that the grass is green and that the sun is hot. But this is our mental map of the world, this is not the physical world.
Many of these ideas came from this very interesting Radiolab podcast below on color and sight. Enjoy!