The City and the Stars Page 0,75

gone, and he was standing once more before the Central Computer in the depths of Diaspar.

It had all been illusion, no more real than the fantasy world of the sagas in which he had spent so many of the hours of his youth. But how had it been created; whence had come the strange images he had seen?

"It was an unusual problem," said the quiet voice of the Central Computer. "I knew that the robot must have some visual conception of the Great Ones in its mind. If I could convince it that the sense impressions it received coincided with that image, the rest would be simple:"

"And how did you do that?"

"Basically, by asking the robot what the Great Ones were like, and then seizing the pattern it formed in its thoughts. The pattern was very incomplete, and I had to improvise a good deal. Once or twice the picture I created began to depart badly from the robot's conception, but when that happened I could sense the machine's growing perplexity and modify the image before it became suspicious. You will appreciate that I could employ hundreds of circuits where it could employ only one, and switch from one image to the other so quickly that the change could not be perceived. It was a kind of conjuring trick; I was able to saturate the robot's sensory circuits and also to overwhelm its critical faculties. What you saw was only the final, corrected image-the one which best fitted the Master's revelation. It was crude, but it sufficed. The robot was convinced of its genuineness long enough for the block to be lifted, and in that moment I was able to make complete contact with its mind. It is no longer insane; it will answer any questions you wish."

Alvin was still in a daze; the afterglow of that spurious apocalypse still burned in his mind, and he did not pretend fully to understand the Central Computer's explanation. No matter; a miracle of therapy had been accomplished, and the doors of knowledge had been flung open for him to enter.

Then he remembered the warning that the Central Computer had given him, and asked anxiously: "What about the moral objections you had to overriding the Master's orders?"

"I have discovered why they were imposed. When you examine his life story in detail, as you can now do, you will see that he claimed to have produced many miracles. His disciples believed him, and their conviction added to his power. But, of course, all those miracles had some simple explanation-when indeed they occurred at all. I find it surprising that otherwise intelligent men should have let themselves be deceived in such a manner."

"So the Master was a fraud?"

"No; it is not as simple as that. If he had been a mere impostor, he would never have achieved such success, and his movement would not have lasted so long. He was a good man, and much of what he taught was true and wise. In the end, he believed in his own miracles, but he knew that there was one witness who could refute them. The robot knew all his secrets; it was his mouthpiece and his colleague, yet if it were ever questioned too closely it could destroy the foundations of his power. So he ordered it never to reveal its memories until the last day of the Universe, when the Great Ones would come. It is hard to believe that such a mixture of deception and sincerity could exist in the same man, but such was the case."

Alvin wondered what the robot felt about this escape from its ancient bondage. It was, surely, a sufficiently complex machine to understand such emotions as resentment. It might be angry with the Master for having enslaved it -and equally angry with Alvin and the Central Computer for having tricked it back into sanity.

The zone of silence had been lifted; there was no further need for secrecy. The moment for which Alvin had been waiting had come at last. He turned to the robot, and asked it the question that had haunted him ever since he had heard the story of the Master's saga.

And the robot replied.

Jeserac and the proctors were still waiting patiently when he rejoined them. At the top of the ramp, before they entered the corridor, Alvin looked back across the cave, and the illusion was stronger than ever. Lying beneath him was a dead city of strange white buildings, a city bleached by a