“If we knew thoroughly the nervous system of Shakespeare . . . we should be able to show why . . . his hand came to trace on certain sheets of paper those crabbed little black marks which we . . . call the manuscript of Hamlet. We should understand the rationale of every erasure and alteration therein . . . without in the slightest degree acknowledging the existence of the thoughts in Shakespeare’s mind. The words and sentences would be taken, not as signs of anything beyond themselves, but as little outward facts, pure and simple.”