This eye test says the boundary I use to define the difference between green and blue is between hues 174 and 168 (I took it a few times), but I’m not really sure what that tells me. I guess it’s just semantic— we could all see the same color but call it something different. I don’t think we have a way to actually prove if we see things the same way.
When I was a kid my friend and I had a recurring conversation about the idea that we could be perceiving the world differently and not know it. We wondered about a scenario where two people agreed on the name of every color they saw, even though their eyes were showing their brains two different shades. For them, all colors would be relatively the same (like a color wheel spun some number of degrees clockwise, with the labels staying stationary), while the real truth would be undiscoverable.
But also, maybe the language we use actually changes our understating and experience of the colors. Like Orwell’s idea that having a smaller vocabulary does not just limit your ability to describe the world, but limits your understanding too. Maybe turquoise isn’t green or blue. The ancient Greeks apparently did not have a regular word for “blue”. The Iliad describes “the wine dark sea.” But did they simply choose to group blue in with red/purple, or did they literally not see it as blue, either due to a biological difference in our eyes, or a psychological difference produced by language restrictions.
I don’t know, whatever. The blue I see is probably my favorite color.