Standard deontic logic wisely forbids doing the impossible. After all, if you are permitted to do something, then you are permitted to do anything that it entails. Permitting Ivan Karamazov to become distinct from himself would make everything permissible – including his destruction of Moscow! Enter the logical fatalist. She says there is exactly one possible world. She deduces a morality that specifies every detail of our lives. Demanding! But since that morality compresses to the commandment `Do what you actually do’, fatalism guarantees we will meet all of our obligations. Lenient! Although not designed as a morality, fatalism triggers deontic logic into crystallizing a complete account of everyone’s obligations. Whereas Arthur Prior derives an `ought’ from an `is’, the fatalist derives an `ought’ without an `is’! Non-fatalists can do the same for the impossibilities they acknowledge (doing in miniature what fatalist does at a dramatic scale). This logical point has affected the fatalism of the Stoics, Spinoza, and the crypto-fatalism of Gottfried Leibniz and David Lewis. Its influence is easiest to discern in their vulnerability to the lazy argument – first deployed against2 the Stoics and then reincarnated as the moral passivity objection to modal realism.