"But that doesn't mean a thing."
In the privacy of his study Martin Grant allowed himself to become excited. Fred had unwittingly come upon the vital clue to the two disappearances.
"Let's be clear about this," he said to himself, drumming on his desk nervously with his fingers. "Undoubtedly there's a connection between the vanishing and my theory. Both Horace and John arrived at something I've missed. And since my theory is exhaustive it can't be there. It must be—yes—it must be that they went a step farther." He pondered this a moment and added grudgingly, "A step I have missed." Then even more grudgingly, "An obvious step."
Automatically he opened a drawer and brought out a sheet of paper and a pencil. He wrote:
The theory contains within itself the proof that the universe must, by logical necessity, be constructed according to said theory. But observation and experience say this is not true.
He frowned at what he had written. This was the conclusion to which he had led both men. It was the conclusion upon which he had rested. They, obviously, had not rested there. They had gone on.
Under what he had written he wrote "Either:" on the left hand margin. Two inches under it he wrote, "Or:" Then he frowned at them. Suddenly he began writing rapidly after the Either: "The universe is not constructed according to logical necessity."
He hesitated, studying what he had written. Then, pursing his lips, he slowly wrote after the Or: "The observable universe is not the universe."
He nodded to himself. That hit at the core of the matter. A was X. B was not X. Therefore B was not A. Even though A and B were both called universe.