the blindfold supper: the ear reads the ball better than the eye

Thorp's experimental theory makes the tennis body an acoustic instrument: Dymphna judges "the necessary spot of landing by the intensity of the sound of the ball against the opponent player’s string" — reading trajectory off the crack of contact instead of watching the flight. The sighted player extends the ball's beginning imaginatively; the blind one hears the whole shot in a single variation of intensity. It's the body-as-instrument argument at full stretch: the relevant input isn't light, it's sound, and the ear can be trained into a finer racquet-eye than the eye.