Robertson followed anxiously. He interrupted, “Too much for The Brain to handle?”

Lanning shook his head decisively, “No. There are no known limits to The Brain’s capacity. It’s a different matter. It’s a question of the Robotic Laws. The Brain, for instance, could never supply a solution to a problem set to it if that solution would involve the death or injury of humans. As far as it would be concerned, a problem with only such a solution would be insoluble. If such a problem is combined with an extremely urgent demand that it be answered, it is just possible that The Brain, only a robot after all, would be presented with a dilemma, where it could neither answer nor refuse to answer. Something of the sort must have happened to Consolidated’s machine.”

He paused, but the general manager urged on, “Go ahead, Dr. Lanning. Explain it the way you explained it to me.”

Lanning set his lips and raised his eyebrows in the direction of Dr. Susan Calvin who lifted her eyes from her precisely folded hands for the first time. Her voice was low and colorless.

“The nature of a robot reaction to a dilemma is startling,” she began. “Robot psychology is far from perfect—as a specialist, I can assure you of that—but it can be discussed in qualitative terms, because with all the complications introduced into a robot’s positronic brain, it is built by humans and is therefore built according to human values.

“Now a human caught in an impossibility often responds by a retreat from reality: by entry into a world of delusion, or by taking to drink, going off into hysteria, or jumping off a bridge. It all comes to the same thing—a refusal or inability to face the situation squarely. And so, the robot. A dilemma at its mildest will disorder half its relays; and at its worst it will burn out every positronic brain path past repair.”

“I see,” said Robertson, who didn’t. “Now what about this information Consolidated’s wishing on us?”

“It undoubtedly involves,” said Dr. Calvin, “a problem of a forbidden sort. But The Brain is considerably different from Consolidated’s robot.”

“That’s right, chief. That’s right.” The general manager was energetically interruptive. “I want you to get this, because it’s the whole point of the situation.”

Susan Calvin’s eyes glittered behind the spectacles, and she continued patiently, “You see, sir, Consolidated’s machines, their Super-Thinker among them, are built without personality. They go in for functionalism, you know—they have to, without U.S. Robot’s basic patents for the emotional brain paths. Their Thinker is merely a calculating machine on a grand scale, and a dilemma ruins it instantly.

“However, The Brain, our own machine, has a personality—a child’s personality. It is a supremely deductive brain, but it resembles an idiot savante. It doesn’t really understand what it does—it just does it. And because it is really a child, it is more resilient. Life isn’t so serious, you might say.”

The robopsychologist continued: “Here is what we’re going to do. We have divided all of Consolidated’s information into logical units. We are going to feed the units to The Brain singly and cautiously. When the factor enters—the one that creates the dilemma—The Brain’s child personality will hesitate. Its sense of judgment is not mature. There will be a perceptible interval before it will recognize a dilemma as such. And in that interval, it will reject the unit automatically—before its brain-paths can be set in motion and ruined.”