“What sort of an imaginary voice is that? I asked myself, suppose Columbus had heard an imaginary voice telling him to sail west. And because of it he had discovered the New World and changed human history... We would be hard put to defend the use of the term 'imaginary' then, for that voice, since the consequences of its speaking came to affect us all. Which would have constituted greater reality, an 'imaginary' voice telling him to sail west, or a 'real' voice telling him the idea was hopeless?”