"What If My Red Is Your Green?" is a question I ask myself for many years now. As a photographer this question/issue was always on my mind: I work so hard to get (what I see as) the perfect colors, and what I see as beautiful, but I have no way to know if the colors I see are the same colors you see. We all agree that red is red, and green is green. We all know that a lemon is yellow and a strawberry is red. But is it possible that you see yellow the way I see blue? Michael from VSauce did his best to answer the question.
Check out this video from VSauce explaining the issue, why it's hard to prove, and just in general explains how we see colors.