Now, Ostby decided, was the time to ask his vital question. "Don't you think that you and your people would be better off if the 'door' between the worlds were closed?" He held his breath while he waited for the answer.
"You are making a mistake if you associate me, in your mind, with my world's people," the Brain said. "Not having a body to inspire emotion, wants and desires, I am tied to them by nothing. Whether they are better or worse off concerns me not at all. Whether they are happy, or even all die, concerns me equally as little. But you are right. The 'door' is a bad thing for them. This city is a parasite. All its technology, its customs, its sins, its vices, are copied from your Earth. Without the 'door' this city, this artificial oddity, would vanish. Its inhabitants would disperse and resume their pastoral life, where, I assure you, they would be much happier.
"And the solution to this is, as you say, the closing of the 'door.' Because every machine we have, that we did not steal, is manufactured by captives from Earth."
He was in too deep to back out now, Ostby decided. He plunged recklessly into the next question. "Can you tell me something about the operation of the 'door'?"
"This is not the first time the 'door' has appeared between our worlds," the Brain said, "though I know very little about its original appearance. Practically all I know about that is the result of abstract speculation. It appeared at least once before, thousands of years ago. My own theory is that at that time there was a mass migration from our world to yours, and that the present Earth people are descendants of our own ancestors."
The Brain paused for a long minute before continuing. "I have studied many of the writings of the Earth, and am quite certain that I know more about its history than its average citizen. Do you recall the evidence found concerning the Cro-Magnon man of Earth's prehistoric ages? It seems that the so-called Neanderthal man was the animal that most nearly approached the present homo sapiens, until suddenly—as such things are reckoned—he was supplanted by another, much more advanced species of man, the Cro-Magnon. My research leads me to believe that those Cro-Magnon men migrated from our world to yours!"
A dozen questions sprang to Ostby's mind concerning this fascinating theory, but he put them aside impatiently. He was a man with a bulldog tenacity of purpose, and he had no intention of wasting time on questions prompted by idle curiosity.
"That's a very interesting theory," he said, "and I would like to discuss it more fully some other time. But for now, are you telling me that the 'door' is a natural phenomenon?"
"Not the present 'door,'" the Brain replied. "It was created, approximately twenty years ago, by the concentration and intellectual power of one mind—my own!"