People grow up believing that the world looks the same to everyone. From a young age everybody is taught what colors are: “This is purple” or “This is green.” It feels like a fact everybody shares. The more it’s thought about, the less certain that becomes.
Sensory processing varies from one person to the next. These are not just limited to senses like sound or touch. There are millions of different colors and constantly more being created. Yet based on the way colors are taught and learned in school and through popular culture, it is assumed that when two people look at the same color they experience it the exact same way. That assumption is convenient, but not something anybody can actually prove.
What is called “purple” might not look the same to everyone else. My “green” could be somebody else’s “purple” and no one would ever know. This is because everyone was taught to call it that color even before they enter school. They are taught through pictures where they are told what they should be perceiving.
Two people can look at the same thing and genuinely experience it differently, not because one is wrong, but because human perception is not identical. This theory may never be proven, but hopefully with new technology, it will be settled right or wrong.