Way back on page 514 there was something worth writing about, an update on Donald Rumsfeld's sole contribution to humanity: he talked about known knowns, known unknowns, and unknown unknowns, a useful way to look at problems. What Rumsfeld missed, says Pinker citing Dominic Johnson citing Slavoj Zizek, is unknown knowns, which are things known or knowable but are ignored or suppressed.
The context for Pinker was unknown knowns that Rumsfeld and the Bushies had in front of them about Iraq - lack of nuclear weapons development particularly, and the lack of a plan for governing the country. Unknown knowns applies even better to climate change - the evidence is hitting us in the face, literally so in some cases, and mountains of data and history available for anyone to see, but half of American politics refuses to see it. I doubt we'll get the hardcore denialists to know them, but we need to move the fencesitters so they're not stuck by the same unknown knowns.
UPDATE: lifted from someone else's comment:
If the rational course of action involves admitting that you cannot have what you most want, don't bet on the persons involved being rational.