The quote by Henry David Thoreau is saying we can look at everything thing around us but at the end the only thing that matters is what we choose to take in. To take in what matters does not have to be everything but only the most important to you.
"Progress is impossible without change & those who cannot change their minds cannot change anything." - George Bernard Shaw This is among my favorite sayings. Inability to change, reconsider or rethink is a true sign of iGNORANCE.