the act of writing it was part of a strategy to conserve willpower that he used over and over with great success: precommitment. The essence of this strategy is to lock yourself into a virtuous path. You recognize that you’ll face terrible temptations to stray from the path, and that your willpower will weaken. So you make it impossible—or somehow unthinkably disgraceful or sinful—to leave the path. Precommitment is what Odysseus and his men used to get past the deadly songs of the Sirens.
