Wallace says it himself in the speech: " Twenty years after my own graduation, I have come gradually to understand that the liberal arts cliché about teaching you how to think is actually shorthand for a much deeper, more serious idea: learning how to think really means learning how to exercise some control over how and what you think. It means being conscious and aware enough to choose what you pay attention to and to choose how you construct meaning from experience. Because if you cannot exercise this kind of choice in adult life, you will be totally hosed. Think of the old cliché about “the mind being an excellent servant but a terrible master.”

I second this nomination. This is one of the most insightful essays I've ever read. Wallace's central points of consciously choosing A) what you give your attention to and B) how you construct meaning from experience REALLY DO lie at the heart of learning how to think and live a meaningful life.

("Water" is the noise in life that surrounds us every day which we've learned to ignore. But it's still the lens through which an untrained eye sees everything, that shapes who we are and how we live, since most of us don't act deliberately so much as react to life. Being oblivious to water is about remaining clueless to this noise, just going with the flow, unquestioningly and passively allowing your view of the world and your role in life to be shaped by mostly meaningless turbulence.)