A parallel would be a trained singer who, through years of practice, knows what the notes feel like vibrating inside. Then she is giving a concert in a big venue and the sound system is a nightmare. From onstage, she can’t hear herself at all—a surprisingly common occurrence. The great performer can deliver a virtuoso performance without hearing a thing, because she knows how the notes should feel coming out, even if her primary monitor—her ears—are temporarily unavailable.
