OR, MEMENTO MORI Part One-- The episode is post-doc and post-op. The Natural Philosopher Democritus trained himself by going into solitude and frequenting mausolea and tombs. And Plato's Phaedo, wherein the death of Socrates is recounted, introduces the idea that the proper practice of Philosophy is "about nothing else but dying and being dead." The Stoics of classical antiquity were notoriously prominent, as it were, in their use of this discipline, and Seneca's letters are full of injunctions to meditate on Death. We hope it helped him, tutor to the uncontrollable Nero, when that emperor later gave the order for his execution. Another Stoic of note, Epictetus, author of the immortal Enchiridion, told his students that when kissing their children, brothers, or friends, they should remind themselves that they themselves are mortal, curbing their pleasure, as do "those who stand behind men in their triumphs and remind them that they are mortal." The Stoic Marcus Aurelius invited the reader (himself) to "consider how ephemeral and mean all mortal things are" in his Meditations. About that character standing behind you in the chariot: In some accounts of the Roman triumph, a companion or public slave would stand behind or near the triumphant general in his garlanded chariot during the procession and remind him, from time to time of his own mortality ("Remember, thou art mortal"), or prompt him to "look behind." You never know Who might be back there.