The term you're looking for is "qualia" - one's own experience of sensory inputs, which cannot be compared with others' except through allegory.

The scenario you're describing seems like more of a language thing than a perception thing. We generally learn names of colors by references to common objects. I would argue that if people agree something is "Red, like a strawberry, tomato, or apple" then it doesn't really matter what you're seeing, that color is red.

I vividly remember my friend and I first thinking of this question during a sleepover at around 13 years old, as we stayed awake late talking about what seemed at the time like the deep philosophies of life. This isn't to say that it's a bad question, but more that it's funny how everyone seems to come up with this question independently at some point. I've read many others with the same question since.

Yup, always wondered this as well! The word for each internal subjective experience is called qualia.

Pretty much impossible to prove the original question until we're able to see through someone else's eyes and brain (if we ever get there, that's probably the least of our philosophical worries :D)

Have I got a Wikipedia article for you!

https://en.wikipedia.org/wiki/Qualia

We know for a fact that bees or dogs perceive color very differently. But in between humans, the perception of physical sensations can still be resolved when we consider near-identical genetics.

But it's way more fun when you apply it to abstract concepts like love, happiness, or fear!

"Wittgenstein's beetle" is the mind-blowing concept for today if you want to dive deeper into this rabbit hole :)

If you want to explore it further, look up the philosophical aspects of the hard problem of consciousness. [1]

[1] https://en.wikipedia.org/wiki/Hard_problem_of_consciousness

It would be interesting to see if llms all share the same internal representation of red. It might hint towards how it works for humans.

Note: I'm not sure this is formulated well, or even if I am able to articulate this correctly.

Chemistry is the same for each of us, as is physics, so I'd be inclined to think that red is the same red for everyone.

I have thought about this many times. The same could be asked about other senses as well like taste, do we both interpret the taste of a banana the same?

At the end of the day what exactly are our senses? Are they simply our brains interpretation of the energies that surround us?

Apparently about 4.4% of the population experiences chromesthesia in which they have a blending of their senses and will see colors or shapes when hearing music.

My opinion is that it is impossible to know and if I had to bet I would bet that we all experience things slightly different. That is only based on the thought that from an evolutionary standpoint we already have many diverse traits from one another. It's another one of those philosophical thoughts we most likely could never answer.