Private Nature of Perceptual Experience

Two people look at an apple. What is their experience of the apple's color and how do their two experiences compare? If they both say the apple looks “red,” does this mean their perceptions are the same? This entry presents evidence supporting the idea that it is likely that people experience the same stimuli differently, and also considers the idea that because the essence of our experience is essentially private and can't be shared with others, it is difficult or impossible to determine when people's perceptions are the same. Related to the private nature of human perception is the issue of whether it is possible to know what animals experience.