Abstract: Why do revolutions happen? Why are they so difficult to anticipate? Some of the most instructive answers point to three factors: (1) preference falsification on the part of rebels or revolutionaries; (2) diverse thresholds for revolutionary activity; and (3) social interactions that do or do not trigger the relevant thresholds. Under conditions of actual or perceived injustice or oppression, true preferences and thresholds are probably impossible to observe; social interactions are impossible to anticipate. Even if we could observe (1) and (2), the challenge of anticipating (3) would make it essentially impossible to foresee revolutions. For all their differences, and with appropriate qualifications, the French Revolution, the Russian Revolution, the fall of Communism, and the Arab Spring were unanticipated largely for these reasons. And in light of (1), (2), and (3), it is hazardous to think that the success of successful revolutions is essentially inevitable. (The same is true for the failure of unsuccessful revolutions.) History is only run once, so we will never know, but small or serendipitous factors might have initiated (or stopped) a revolutionary cascade. The #MeToo movement can be seen as such a cascade, marked by (1), (2), and (3). For that movement, as for successful revolutions, we might be able to point to some factors as necessary conditions, but hindsight is hazardous. It is also important to note that in revolutions, as in #MeToo, preferences and beliefs are not merely revealed; they are also transformed. Revolutionary activity, large or small, puts issues about preference falsification, experience falsification, and adaptive preferences in a new light.