"Second: Today, twenty-five million years later, we observe two sets of individuals, ourselves and the Lunarians. Fact.

"Third: We and the Lunarians are identical. Fact.

"Now, if we accept the principle that divergence must have occurred, what must we conclude? Ask yourselves—If confronted by those facts and nothing else, what would any scientist deduce?"

Danchekker stood facing them, pursing his lips and rocking back and forth on his heels. Silence enveloped the room, broken after a few seconds by his whistling quietly and tunelessly to himself.

"Christ . . . !" The exclamation came from Hunt. He stood gaping at the professor in undisguised disbelief. "They couldn't have been isolated from each other," he managed at last in a slow, halting voice. "They must both be from the same . . ." The words trailed away.

Danchekker nodded with evident satisfaction. "Vic's seen what I am saying," he informed the group. "You see, the only logical conclusion that can be drawn from the statements I have just enumerated is this: If two identical forms are observed today, they must both come from the same isolated group. In other words, if two lines were isolated and branched apart, both forms must lie on the same bronchi."

"How can you say that, Chris?" someone insisted. "We know they came from different branches."

"What do you know?" Danchekker whispered.

"Well, I know that the Lunarians came from the branch that was isolated on Minerva . . ."

"Agreed."

". . . And I know that man comes from the branch that was isolated on Earth."

"How?"

The question echoed sharply around the walls like a pistol shot.

"Well . . . I . . ." The speaker made a gesture of helplessness. "How do I answer a question like that? It . . . it's obvious."

"Precisely!" Danchekker showed his teeth again. "You assume it—just as everybody else does! That's part of the conditioning you've grown up with. It has been assumed all through the history of the human race, and naturally so—there has never been any reason to suppose otherwise." Danchekker straightened up and regarded the room with an unblinking stare. "Now perhaps you see the point of all this. I am stating that, on the evidence we have just examined, the human race did not evolve on Earth at all. It evolved on Minerva!"

"Oh, Chris, really . . ."

"This is getting ridiculous . . ."

Danchekker hammered on relentlessly: "Because, if we accept that divergence must have occurred, then both we and the Lunarians must have evolved in the same place, and we already know that they evolved on Minerva!"

A murmur of excitement mixed with protest ran around the room.