Hidden Brain played a clip of a radical-honesty advocate describing a life with nothing held back, and Shankar Vedantam asked Pinker whether that works in practice. Pinker's answer was flat: to put it mildly, no. He argues that in a world of total candor there are no relationships left, only transactions, and reaches for Pascal's line that if everyone said what was on their minds there would not be four friends in the world.