There is a difference between hearing Clyde play the piano and seeing him play the piano. The difference consists in a difference in the kind of experience caused by Clyde's piano playing. Clyde's performance can also cause a belief – the belief that he is playing the piano. A perceptual belief that he is playing the piano must be distinguished from a perceptual experience of this same event. A person (or an animal, for that matter) can hear or see a piano being played without knowing, believing, or judging that a piano is being played. Conversely, a person (I do not know about animals) can come to believe that Clyde is playing the piano without seeing or hearing him do it – without experiencing the performance for herself.

This distinction between a perceptual experience of x and a perceptual belief about x is, I hope, obvious enough. I will spend some time enlarging upon it, but only for the sake of sorting out relevant interconnections (or lack thereof). My primary interest is not in this distinction but, rather, in what it reveals about the nature of conscious experience and, thus, consciousness itself. For unless one understands the difference between a consciousness of things (Clyde playing the piano) and a consciousness of facts (that he is playing the piano), and the way this difference depends, in turn, on a difference between a concept-free mental state (e.g., an experience) and a concept-charged mental state (e.g., a belief), one will fail to understand how one can have conscious experiences without being aware that one is having them.