Despite the near universal desire for happiness, relatively little philosophy has been done to determine what “happiness” means. In this paper I examine happiness (in the long‐term sense), and argue that it is best understood in terms of tranquillity. This is not merely “contentment.” Rather, happiness requires reflection—the kind of reflection characteristic of philosophy. Happiness is the product of correctly assessing its conditions, and like any assessment, one can be mistaken, and thus mistaken about whether one is happy. That is, (...) one needs a correct understanding of happiness in order to be happy. (shrink)