“I’ll ask.”

Ariel looked at him blankly, but it wasn’t a lack of recognition. It was more a lack of energy. “Oh, Derec. How are you?”

What do you say to someone who may be alive tomorrow, but won’t remember you? If Derec’s memories had been a hundred years long rather than a couple of months, he still wouldn’t have had anything to guide him.

“Well enough,” he said awkwardly. He drew near to the bed, touched it. She looked at him without much emotion.

“Are you going to help them restore my memory?”

“Of course. I’ll have to. And I hope you’ve been talking-?” He indicated the robots with a tilt of his head.

“A little,” she said reluctantly. “I’m so tired all the time. And they keep me so full of drugs I don’t have the spirit. Besides, it doesn’t matter. It won’t help. It w-won’t really be me. Derec, it’s like dying. It’s just like dying. I won’t see you again-I won’t see anyone again-it’s all fading-”

One of the robots sprang to the head of the bed and did something, and Ariel’s eyes closed. When they opened after a moment the horror had largely passed. Derec thought it was still there, though, masked by the drug.

“That isn’t so, Ariel,” he said insistently. “Your memories are still there, in your brain. They merely need to be unlocked. We’ll-”

She was shaking her head. “No, it’s all going. I’m dying, Derec. Whoever takes my place will be someone different.”

Abruptly he said, “Am I different than-the man I was?”

“Of course. And yet, you’re him.” She closed her eyes and tears trembled on her eyelids. The robot got busy at the headboard again.

“Derec, I want you to know that I’ve always loved you. Even when I was most angry, even when I was most frightened. I never blamed you. For weeks I’ve watched, hoping you would never develop the final form of the disease. I guess you did, or you wouldn’t have lost your memory. Whoever cured you…didn’t have the…technology to restore…your memory…”

She drifted off into sleep, and after a moment Derec choked down his impulse to cry out, to demand that they awaken her. Suddenly his lost memory seemed less important, what she knew seemed less important, than what she thought of him.

“Farewell, Ariel,” he managed to say huskily, and stumbled out into the Friends’ Lounge, where he sat and wept for a time, quietly. He wondered vaguely if, in all his unremembered life, he had felt this sharp, poignant pain, and doubted it. Yet, he had known her in another life, and it had not been wholly a happy relationship.

He’d had amnemonic plague; the emptiness in his head was proof enough for him. Had he gotten it from her-or given it to her?

Presently he took a deep breath, let it out in a sigh that came from the bottom of his belly, and wiped his face on a tissue from the dispenser. Robots were probably watching him; within minutes Dr. Li and a weary-looking Dr. Powell entered the room.

They sat and looked him over while he braced himself. Fortunately, they, like he, had more important things on their minds than Ariel’s ID tags.

“I understand that Korolenko has told you a little about memory restoration,” Dr. Powell said.

Derec remembered an exchange from an earlier visit. He nodded. “Memory traces are not memory. Yes.”

“Quite so. A memory trace is the synapse-the nerve connection in the brain-that leads to the memory, which is stored in chemical form. It is these synapses that are being erased by the neurotoxin of the plague. The actual memories remain untouched.”

They looked at him. If only you knew how much I know about this; he thought. “Right,” he said. “But since their addresses are unknown-to put it in computer jargon-the memories are as lost as if the records had been wiped.”

“Almost,” said Dr. Li. “There are ghost memories flitting about the patient’s mind, and many little things will jolt a few of the memories loose.”

“Smell is one of the subtlest and most powerful memory keys,” said Dr. Powell, nodding.

Derec knew. “Yes.”

“So. In what we loosely call a memory restoration, we merely supply new synapses as nearly identical to the old as possible.”

“And in the functioning of the new memory traces,” Derec said, parroting what he’d been told, “the patient reactivates the old chemical memories.”

“Quite so. The more accurate and detailed the new memory traces are, the more complete not only the restoration of the memories, but the restoration of the patient’s original personality. I hope you can see that. “

It was an angle that had never occurred to him. He supposed he had the same basic personality as ever: pragmatic, problem-solving, not given to abstract thought, not artistic or poetic. An equable temperament. The engineering mind.

Now that he thought of it, though, perhaps his personality was different. He had known Ariel in his former life. He must have had strong feelings about her. He did again. Not still -again.For if he had not met her since his memory loss, and had not continuously been practically in solitary confinement with her, he might well not have felt that way about her again.

His parents, for instance. He no longer felt about them as he once must have done. His friends-all those parts of his personality were gone. If he acquired new friends, his emotional responses would be much the same, of course. His personality had not changed in any basic way, or so he supposed. He did not seem very strange to Ariel. Still, he was a new and different person from the old Derec, whatever his name had been.

Perhaps Ariel was right; perhaps it was a form of death.

Yet-”If the memory traces are close enough to the original-?”

“Ideally, it would be like copying a program into a blank positronic brain,” said Dr. Li. “The second robot would, for all practical purposes, become the old one.”

“We always explain what’s been done to them,” Derec said absently.

“Yes. But if the original was destroyed-” Derec frowned. “-the new one would, for all intents and purposes, be the same one in a new body.”

True, it was not unlike shifting a positronic brain to a new robotic body. Derec had an uneasy flash. On Robot City there had been an accidental death, of a boy called David, which Derec and Ariel had investigated for the robots. This David had looked just like him

He usually shrugged that fact off, but now he was jolted. Maybe the other was the duplicate-or was it himself?

“In a human, of course, it is not quite so simple,” said Dr. Powell, not noticing his jolted expression. “We could activate a significant fraction of the locked memories without reactivating the old personality. It’s a matter of knowing which memories are important to the patient.”

“How close can we come?” Derec asked.

“It depends on how much we know. The robots are, of course, recording and analyzing everything she says, and there’s a tendency to relive the most important memories first and most often, till they’re gone. So we’re developing a good sketch, too crude to be called a diagram.”

Derec nodded. “That’s where you need my help.”

“Quite so. You know her better than we, or the robots, can hope to.”

“Not well enough, I’m afraid,” said Derec steadily, wishing for some of that tranquilizer they were keeping Ariel on. “I’ve only known her for a few weeks.”

And already married,their expressions said. Spacer morals. Derec didn’t enlighten them. “I can go into a lot of detail about our time together, but before that…she was a very private person.”

Again, their expressions spoke for them: Spacers lived alone, on the surface, surrounded only by robots, and had few human contacts……Not true, but try to explain. Besides, he’d had his own quota of chauvinistic nonsense about Earthers to lose.

“Whatever you can do, you must do,” Dr. Li said heavily.