The textbook for the philosophy class was titled, interestingly, Self and World I underlined a passage by david Hume from an article titled, On Self Identity:

"For my part, when I enter most intimately into what I call myself, I always stumble on some particular perception or other, heat or cold, light or shade, love or hatred, pain or pleasure. I never can catch myself at any time without a perception, and never can observe anything but the perception."

Brían