It’s curious how the mind, despite not knowing the limits to the intensity with which it experiences its states, can hardly reconstitute them accurately. It is much easier to recall acts committed, even if these have generated less intense psychological effects, or even none at all. This seems to show that psychological states only make a mark insofar as they induce some real action; and it is this, after all, that makes them recallable. A very useful precept can be drawn from this: when we want a state of mind to last, we have to act under its influence; when we want to forget it, we just have to entrust its dissipation to inaction.