I had an existential crisis when I was ten years old.
Okay, perhaps I was an overachiever, anxiety-wise. My class was studying the sense, and the subject of differences in individual perception came up, like it does. It’s very likely, my teacher said, that humans perceive things like color, or certain scents or tastes, differently from one another: that I might experience the color I characterize as yellow differently from you. In terms of light and spectra, the color yellow is the color yellow is the color yellow, but my experience of yellow is based on my hardware and software: that is, my eyes and brain, as well as my experiences in interpreting color.
My class had some fun with this; ten year olds are not notably sophisticated about humor, and for a day or two there was a rash of “Nice red shirt,” comments to people who weren’t wearing red, and so forth. In science class the next day, someone asked, if our experiences are all different, how can we knew that yellow is yellow? My teacher fumphed a bit and got sidetracked talking about light and the visible spectrum, and… my classmate never quite got an an answer, but I remember sitting at my desk feeling deeply unsettled.
If my color yellow was not the same as someone else’s color yellow, how could I be sure that the word yellow when I spoke it would sound like yellow to a person I was talking to? How could I make sure that anything I said or experienced was the same thing someone else heard or experienced? Short of crawling into someone else’s head, how could I ever know? Which made me feel as alone as I had ever felt in my young life. I felt suddenly like everyone–me and everyone I loved–were all just individual objects blithering through the world, crossing paths but unable to confirm our experiences. It was a kind of lonely I had never suspected existed, and I lost several nights sleep trying to devise different ways that I could confirm with someone that yellow was yellow.
And then, gradually, the anxiety diminished and I stopped trying to invent telepathy or some other way to contact and verify that the reality I live in is, in fact, consensual. I don’t think about it too much any more–although back in the 1990s I wrote a story about a man who establishes a telepathic connection with a pair of genetically engineered lions–and while he’s delighting in the connection with another being, they’re sizing him up for dinner.
When I think about it, maybe it’s just as well I don’t know what anyone else thinks is yellow.