She laughed. "You'd find—and you'll find—that things consist only of Aristotelian extremes. Either they are non-coincident and therefore very intangible, or you'll find that they are coincident and as untouchable as tungsten carbide to the bare hands. You can walk through non-coincident granite but you couldn't make a dent in coincident tissue paper."
"Then how do my life processes continue? Either I must be breathing coincident—and therefore untouchable and unchangeable air—or I must be breathing non-coincident and therefore untouchable and unchangeable air."
She laughed heartily. "Trouble is, Les Ackerman, you don't really exist; therefore your life processes are unreal."
"Oh—I don't exist, hey? Then what is this that is I?"
"I'll skip the metaphysics," she said with a laugh. "Do you doubt the reality of unreal things?"
"Isn't that a disclaimer in itself?"
She shook her head. "The square root of minus one is an unreal number. It is a pure formulation, and yet it is an important factor. You cannot dig too deeply into any phase of science without using it—and yet it is still an imaginary quantity. It does not truly exist, nor do you. Yet it is there as a formulation, and that is what you—and I should add: I—are, or am, or whichever."
He laughed too, at her confusion. "We are," he said, but it was more of a question than a correction of her grammar.
"We are—and there are and will be others, too."