How can we observe if an object is a color we can’t see?

Question

From what I understand, humans can see red green and blue and everything in the middle. Some animals I’ve heard see more colors than us, so what’s to say that some things in nature are colors that we don’t see? Who’s to say that some apples are red? And instead a different color that we don’t have a name for because we can’t process it?

How can we tell if this “apple” is as a matter of fact “red”.

In: 75

Answer 1

At least we can specifically say that “red” is a specific range of the visible light spectrum, and define the range of wavelengths.

[The same cannot be said for “brown”](https://youtu.be/wh4aWZRtTwU?si=lFER7hUEHB-mL086)