I take it as ha ha only serious. Pinker knows that people are generally appallingly inaccurate and believe untruthful things, and that psychology is right to throw out every other belief and only depend on what it has rigorously verified; but he also knows the rigorous verification has been done on weird subjects and so psychology has thrown out a lot of correct beliefs as well. Accepting this tension is the mark of an educated man, as Aristotle says.