Hey, Vsauce. Michael here. This appears blue. This appears yellow, and this appears green. Those of us with normal color vision can probably agree. But that doesn’t change the fact that color is an illusion. Color as we know it does not exist in the outside world, beyond us, like gravity or protons do. Instead, color is created inside our heads. Our brains convert a certain amount of the electromagnetic spectrum into color. I can measure the wavelength of radiation, but I can’t recreate the experience of color inside your mind. So, how do I know that when you and me look at a strawberry, and this perception occurs [a red strawberry],which I call “red”, that in your brain this perception doesn’t occur [a green strawberry], which you have, of course, also learned to call “red”? We both call it “red”, we communicate effectively, and we walk away, never knowing just how different each of our internal experiences really were.
Of course, we already know that not everybody sees color in exactly the same way. One example would be color blindness. But we can diagnose and discuss these differences because people with the conditions fail to see things that most of us can. Conceivably, though, there could be ways of seeing that we use that cause colors to look differently in different people’s minds without altering their performances on any tests we could come up with. Of course, if that were the case, wouldn’t some people think other colors looked better than others? Or that some colors were more complimentary of others? Well, yeah, but doesn’t that already happen? This matters, because it shows that fundamentally, in terms of our perceptions, we are all alone in our minds.
Let’s say I met an alien from a faraway solar system who, lucky enough, could speak English, but had never, and could never feel pain. I could explain to the alien that pain is sent through the A-delta and C-fibers to the spinal cord, the alien could learn every single cell and pathway and process and chemical involved in the feeling of pain, the alien could pass a biology exam about pain, and believe that pain, to us, is generally a bad thing. But no matter how much he learned, the alien would never actually feel pain. Philosophers call these ineffable raw feelings “qualia”, and our inability to connect words to these raw feelings, our inability to explain and share our own internal qualia is known as the Explanatory Gap.
This gap is confronted when describing color to someone who has been blind their entire life. Tommy Edison has never been able to see. He has a YouTube channel where he describes what being blind is like. It’s an amazing channel. In one video, he talks about colors, and how strange and foreign of a concept it seems to him. Sighted people try to explain, for instance, that red is “hot”, and blue is “cold”, but to someone who has never seen a single color, that just seems weird. And, as he explains, it has never caused him to finally “see” a color.
Some philosophers, like Daniel Dennett, argue that qualia may be private and ineffable simply because of a failure in our own language, not because they are necessarily always going to be impossible to share. There may be an alien race that communicates in a language that causes colors to “appear” in your brain without your retina having to be involved at all. Or, without you ever having to see the color yourself. Perhaps even in English, given millions and billions of words used in just the right way, it may be possible to adequately describe a color such that a blind person could see it for the first time. Or, you could figure out that, once and for all, yes, or no in fact, you and your friend do not see the same red. But for now, it remains the case that we have no way of knowing if my red is the same as your red. Maybe one day our language will allow us to share and find out, or maybe it never will. I know it’s frustrating to not have an answer, but the mere fact that you guys can ask me about my internal experiences, and the mere fact that I can ask my friends, and we can all wonder at the mere concept of qualia is quite incredible, and also quite human.
Animals can do all sorts of clever things we can do. They can use tools, problem solve, communicate, cooperate, exhibit curiosity, plan for the future, and although we can’t know for sure, many animals certainly act as though they feel emotions: loneliness, fear, joy. Apes have even been taught to use language to speak to us humans. It’s a sort of sign language that they’ve used to do everything from answer questions to express emotion, or even produce novel thoughts. Unlike any other animal, these apes are able to understand language and form responses at the level of a two and a half-year-old child. But there’s something that no signing ape has ever done. No ape has ever asked a question. Joseph Jordania’s “Who Asked the First Question?” is a great read on this topic, and it’s available for free online. For as long as we’ve been able to use sign language to communicate with apes, they have never wondered out loud about anything that we might know that they don’t.
Of course, this does not mean that apes and plenty of other animals aren’t curious. They obviously are. But what it suggests is that they lack a theory of mind, an understanding that other people have separate minds, that they have knowledge, access to information, that you don’t have. Even us humans aren’t born with a theory of mind, and there’s a famous experiment to test when a human child first develops a theory of mind. It is called the “Sally-Anne test”. During the test, the researchers tell the children a story about Sally and Anne. Sally and Anne have a box and a basket in their room. They also happen to have a delicious cookie. Sally takes the cookie and puts it inside the box, and then Sally leaves the room. While Sally is gone, Anne takes the cookie out of the box and puts it in the basket. When Sally comes back, the researchers ask the children where Sally will look for the cookie. Obviously, Sally will look in the box. That’s where she left it, and she has no way of knowing what Anne did while she was away. But until about the age of four, the children insist that Sally will look in the basket, because after all, that’s where the cookie is. The child saw Anne move the cookie, so why wouldn’t Sally also know? Young children fail to realize that Sally’s mental representation of the situation, her access to information, can be different than their own. And apes that know sign language but never ask us questions are doing the same thing. They’re failing to realize that other individuals have different cognitive abilities and can be used as sources of information.
So, we are all alone with our perceptions. We are alone in our own minds. We can both agree that chocolate tastes good, but I cannot climb into your consciousness and experience what chocolate tastes like to you. I can never know if my red looks the same as your red. So stay human. Stay curious, and let the entire world know that you are. And as always, thanks for watching.