I hardly know an intellectual man, even, who is so broad and truly liberal that you can think aloud in his society. Most with whom you endeavor to talk soon come to a stand against some institution in which they appear to hold stock – that is, some particular, not universal, way of viewing things. They will continually thrust their own low roof, with its narrow skylight, between you and the sky, when it is the unobstructed heavens you would view. Get out of the way with your cobwebs; wash your windows, I say!
—Henry David Thoreau, “Life Without Principle” (1863)