Michael J. Sandel, Justice: What’s the Right Thing to Do?

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.