philosophy teaches us and unsettles us by confronting us with what we already know; there's an irony: the difficulty consisted in this course is that it teaches what you already know; it works by taking what we know from familiar and unquestioned settings and making it strange. that's how the examples work. ... philosophy estranges us, not by providing us with new information, but by inviting and provoking a new way of seeing. The risk is once the familiar turns strange it is never quiet the same again. Self-knowledge is like a lost innocence, however unsettling, you find it; it can never be unthought or unknown.