“What if the colors you see are different from the colors I see?”
Yawn. Probably almost everybody has heard this worn-out question at least once before. Honestly, I wouldn’t be surprised if most people have even been the one asking the question at least once in their life. It is an interesting thought, after all, and it speaks to the inherent personal-ness of all human experience, or something.
And yet… Most people stop right there. At colors. Even though it’s probably the lowest-hanging fruit on the human qualia totem pole. So low that we’ve already answered the question! We already know for a fact that people don’t see colors the same way. That’s what color blindness is. Of which we also know there are several different kinds!
(Speaking for myself, one of my eyes sees reds slightly duller than the other eye can. So slight that I hardly ever notice it unless I’m specifically looking for it and the lighting and environment are right for me to notice. Maybe that eye has slightly fewer rods/cones for that range of wavelengths? But the point is, it’s possible for one person to see different colors with their own two eyes. So of course different people with different eyes and brains entirely could see even more differently.)
Too many people stop that line of thought at mere colors. What about the other senses? What about hearing? Maybe the sounds I perceive are different from the sounds you perceive. (What’s that? High frequency hearing loss with age is a thing? I guess this one’s also trivial.) Taste? Maybe the cilantro I perceive is different from the cilantro you perceive. (Hold on, I’m getting word from our producers that this was a very cherry-picked example.) Physical touch? (Breaking news: BDSM exists.)
Is that why people don’t ask these questions? Because the answer is always just a plain old “yes, our perceptions might be different”? Are all these examples so far enough to prove that our perceptions are always different? No. Not even close. It would just be bad science to assume the hypothesis is correct this early in the game.
We need to go deeper.
Could it be that the emotion I experience as “sadness” feels like the emotion you experience as “anger”?
If a doctor asks you to rate your pain on a scale from 1 to 10, over the course of a few visits, is it possible that your linear answers of 2-4-6 would correspond to my nonlinear answers of 3-6-5?
The psychic lever you pull to make your brain to send nerve signals down your arm to make your hand into a fist—is it possible that for me, that exact lever is for my leg nerves to twitch my pinky toe?
Eventually, the default question changes from “Is it possible for two people to perceive the same thing differently?” to “Is it possible for two people to perceive anything the same way?” And that question is infinitely harder to answer.