… is from page 140 – and is the closing paragraph – of Thomas Sowell’s superb 1984 book, Civil Rights: Rhetoric or Reality? :
People do not change their vision of the world the way they change clothes or replace old light bulbs. But change they must if they mean to survive. No individual (or group) is going to capture all of reality in his vision. If the only reaction to other visions – or uncomfortable evidence – is blind mudslinging, then the limitations that are common to all human beings become, for them, ideological prisons.