Imagine a perfectly elegant machine parting your skull and unwrapping the precious involutions of your brain into individual strands so that they can be cleaned and washed and healed, and reassembled exactly as they are. Imagine infinitesimal fingers, kind and cool, ravelling up the softness that is you, supporting every link in the chain of consciousness and caressing the agitated nerves, so that even this terrifying touch is a pleasure, the most intimate and most comforting of interventions, like a true love’s hand laying balsams upon an infected wound. Imagine that you could know to a mathematical certainty that every aspect of your identity is being preserved and kept close, so that the whole appalling operation loses no data, not even blood from the cuts around your skull, not even a single cell of your skin. Imagine that the repair, the weld, the weave were all without flaw, and you could relax into the loving dark, and know that when the day is done and the strange, rummaging presence you cannot directly see—and yet perceive with some unheralded sense, some facet of proprioception or quintessential bodily integrity—when all that is done, you will be as you were, and yet more yourself. You will be uplifted and sluiced out and washed so that every functioning part is better than it was. You will play the piano faster, laugh more readily, think more clearly, love more truly.