On the other hand, the fact that Charlie was found on the Moon presupposed a civilization sufficiently advanced technologically to send him there. Surely, on the way toward developing space flight, they would have evolved a worldwide technological society, and in doing so would have made machines, erected structures, built cities, used metals, and left all the other hallmarks of progress. If such a civilization had once existed on Earth, surely centuries of exploration and excavation couldn't have avoided stumbling on at least some traces of it. But not one instance of any such discovery had ever been recorded. Although the conclusion rested squarely on negative evidence, Hunt could not, even with his tendency toward open-mindedness, accept that an explanation along these lines was even remotely probable.

The only alternative, then, was that Charlie came from somewhere else. Clearly this could not be the Moon itself: It was too small to have retained an atmosphere anywhere near long enough for life to have started at all, let alone reach an advanced level—and of course, his spacesuit showed he was just as much an alien there as was man.

That only left some other planet. The problem here lay in Charlie's undoubted human form, which Caldwell had stressed although he hadn't elected to go into detail. Hunt knew that the process of natural evolution was accepted as occurring through selection, over a long period, from a purely random series of genetic mutations. All the established rules and principles dictated that the appearance of two identical end products from two completely isolated families of evolution, unfolding independently in different corners of the universe, just couldn't happen. Hence, if Charlie came from somewhere else, a whole branch of accepted scientific theory would come crashing down in ruins. So—Charlie couldn't possibly have come from Earth. Neither could he possibly have come from anywhere else. Therefore, Charlie couldn't exist. But he did.

Hunt whistled silently to himself as the full implications of the thing began to dawn on him. There was enough here to keep the whole scientific world arguing for decades.

* * *

Inside the Westwood Biological Institute, Caldwell, Lyn Garland, Hunt, and Gray were met by a Professor Christian Danchekker. The Englishmen recognized him, since Caldwell had introduced them earlier by vi-phone. On their way to the laboratory section of the institute, Danchekker briefed them further.