Robot Dreams Part 1

Robot Dreams.

ISAAC ASIMOV.

Introduction.

Science fiction has certain satisfactions peculiar to itself. It is possible, in trying to portray future technology, to hit close to home. If you live long enough after writing a particular story, you may actually have the pleasure of finding your predictions reasonably accurate and yourself hailed as a sort of minor prophet.

This has happened to me in connection with my robot stories, of which "Light Verse" (included here) is an example.

I began writing robot stories in 1939, when I was nineteen years old, and, from the first, I visualized them as machines, carefully built by engineers, with inherent safeguards, which I called "The Three Laws of Robotics." (In doing so, I was the very first to use the word "robotics" in print, this taking place in the March, 1942 issue of Astounding Science Fiction.) Astounding Science Fiction.) As it happened, robots of any kind were not really practical until the mid-1970s when the microchip came into use. Only that made it possible to produce computers that were small enough and cheap enough, while possessing the potentiality for sufficient capacity and versatility, to control a robot at nonprohibitive expense.

We now have machines, called robots, that are computer-controlled and are in industrial use. They increasingly perform simple and repet.i.tious work on the a.s.sembly lines-welding, drilling, polis.h.i.+ng and so on-and they are of increasing importance to the economy. Robots are now a recognized field of study and the precise word that I invented is used for it-robotics.

To be sure, we are only at the very beginning of the robotic revolution. The robots now in use are little more than computerized levers and are very far from having the complexity necessary for the Three Laws to be built into them. Nor are they anything close to human in shape, so they are not yet the "mechanical men" that I have pictured in my. stories, and that have appeared on the screen innumerable times.

Nevertheless, the direction of movement is clear. The primitive robots that have come into use are not the Frankenstein-monsters of equally primitive science fiction. They do not l.u.s.t for human life (although accidents involving robots can result in human death, just as accidents with automobiles or electrical machinery can). They are, rather, carefully designed devices intended to relieve human beings of arduous, repet.i.tive, dangerous, nonrewarding duties so that, in intent and in philosophy, they represent the first steps toward my story-robots.

The steps that are yet to come are expected to proceed further in the direction I have marked out. A number of different firms are working on "home robots" that will have a vaguely human appearance and will fulfill some of the duties that once devolved on servants.

The result of all this is that I am held in considerable regard by those working in the field of robotics. In 1985, a fat encyclopedic volume ent.i.tled Handbook of Industrial Robotics Handbook of Industrial Robotics (edited by s.h.i.+mon Y. Nof and published by John Wiley) appeared, and, on request of the editor, I supplied it with an introduction. (edited by s.h.i.+mon Y. Nof and published by John Wiley) appeared, and, on request of the editor, I supplied it with an introduction.

Of course, in order to appreciate the accuracy of my predictions, I had to be fortunate enough to be a survivor. My first robots appeared in 1939, as I say, and I had to live for over forty more years in order to discover I was a prophet. Because I had begun at a very early age, and because I was fortunate, I managed to do this and words cannot tell you how grateful I am for that.

Actually, I carried on my predictions of the future of robotics to the very end, to the ultimate moment, in my story "The Last Question," published in 1957. I have a sneaking suspicion that, if the human race survives, we may continue to progress in that direction in some ways anyway. Still, survival is limited at the best, and I have no chance of seeing very much more of the future course of technology. I will have to content myself with having future generations witness and (I hope) applaud what triumphs of this sort I may gain. I, myself, won't, Nor are robots the only area in which my crystal ball was clear. In my story "The Martian Way," published in 1952, I described a s.p.a.ce walk quite accurately, although an actual feat of this sort didn't take place till fifteen years afterward. Foreseeing s.p.a.ce walks was not a very daring piece of prescience, I admit, for, given s.p.a.ces.h.i.+ps, such things would be inevitable. However, I also described the psychological effects and thought of one that was rather unusual-particularly for me.

I am, you see, a p.r.o.nounced acrophobe with an absolute terror of heights and know perfectly well that I will never voluntarily go on a s.p.a.ces.h.i.+p. If, however, I were somehow forced on one, I know, too, that I would never dare leave it for a s.p.a.ce walk. Nevertheless, I put personal fear to one side and imagined the s.p.a.ce walk to produce euphoria. I had my s.p.a.ce travelers quarrel over whose turn it was to get out into s.p.a.ce and drift in quiet peace among the stars. And when s.p.a.ce walks became fact, such euphoria was was felt. felt.

In my story, "The Feeling of Power," published in 1957, I made use of pocket computers, about a decade before the real thing came along. I even considered the possibility that such computers might seriously decrease the ability of people to do arithmetic in the old-fas.h.i.+oned way, and that is a real concern of educators now.

As a final example, in my story "Sally," published in 1953, I described computerized cars that had almost reached the stage of having lives of their own. And, in the last few years, we do indeed have computerized cars that can actually talk to the driver-although their abilities in this direction are, as yet, very simple.

Yet, if there is the possibility of this satisfaction from accurate prophecy in science fiction, there is also the reverse. Science fiction offers its writers chances of embarra.s.sment that no other form of fiction does.

After all, if we may prove accurate in our predictions, we may prove inaccurate as well, sometimes ludicrously so.

Such embarra.s.sment becomes particularly acute when one's stories are reprinted in a collection such as this one. When an author starts young, lives out a normal lifetime (as I seem to be doing) and has written continuously, there is likely to be included in the collection stories that were written and published thirty and forty years before and that leave ample scope for any cloudiness in the crystal ball to show up.

This doesn't happen to me as often as it might, for I have several things going for me. In the first place, I am well acquainted with science and am not likely to be wrong in fundamentals. Secondly, I am cautious in my predictions and do not flail away madly in contravention of scientific principles.

Nevertheless, science does advance and sometimes produces completely unexpected results in a very few years, and this may leave a writer (even me) high and dry on a pinnacle of false "facts. " The worst luck I had in this respect turned up in connection with a series of science fiction novels I wrote for youngsters between 1952 and 1958.

That series dealt with the continuing adventures of my heroes on various planets of the solar system, and in each case, I carefully described the planets in strict accordance with what was known about them at the time.

Unfortunately, it was in the course of those very years that microwave astronomy was developed and shortly after those years that rocket probes began to be sent out. The result was that our knowledge of the solar system was startlingly advanced and we learned something new and unexpected about every single planet.

For instance, in my description of Mercury in Lucky Starr and the Big Sun of Mercury, Lucky Starr and the Big Sun of Mercury, I had it facing one side to the Sun, as astronomers then thought-and that was essential to the plot. As it happens, however, we now know that Mercury turns slowly and that every portion of its surface gets sunlight part of the time. There is no "dark side." I had it facing one side to the Sun, as astronomers then thought-and that was essential to the plot. As it happens, however, we now know that Mercury turns slowly and that every portion of its surface gets sunlight part of the time. There is no "dark side."

In my description of Venus in Lucky Starr and the Oceans of Venus, Lucky Starr and the Oceans of Venus, I had a planetwide ocean, which, at that time, seemed at least possible. It was essential to the plot as well. However, we now know that the surface of Venus is at a temperature far above the boiling point of water, and an ocean-or even a I had a planetwide ocean, which, at that time, seemed at least possible. It was essential to the plot as well. However, we now know that the surface of Venus is at a temperature far above the boiling point of water, and an ocean-or even a drop- drop-of liquid water on its surface is totally impossible.

As for Mars, in my book David Starr: s.p.a.ce Ranger, David Starr: s.p.a.ce Ranger, I managed to get the description right in many ways. However, I didn't take advantage of the huge extinct Martian volcanoes that were discovered about fifteen years after the book was published. What's more, I did talk about the ca.n.a.ls (dry ones), which were found to be nonexistent, and I introduced intelligent Martians remaining from a long-dead surface civilization, and this is really extremely unlikely. I managed to get the description right in many ways. However, I didn't take advantage of the huge extinct Martian volcanoes that were discovered about fifteen years after the book was published. What's more, I did talk about the ca.n.a.ls (dry ones), which were found to be nonexistent, and I introduced intelligent Martians remaining from a long-dead surface civilization, and this is really extremely unlikely.

Jupiter and its satellites appeared in Lucky Starr and the Moons of Jupiter, Lucky Starr and the Moons of Jupiter, and while I was careful to describe all the worlds, I naturally missed some major points that were not discovered till twenty years afterward. I said nothing of the cracked world-girdling glacier of Europa and nothing of Io's active volcanoes. I didn't mention Jupiter's huge magnetic field. Nor, in and while I was careful to describe all the worlds, I naturally missed some major points that were not discovered till twenty years afterward. I said nothing of the cracked world-girdling glacier of Europa and nothing of Io's active volcanoes. I didn't mention Jupiter's huge magnetic field. Nor, in Lucky Starr and the Rings of Saturn, Lucky Starr and the Rings of Saturn, did I mention some of the interesting features of the Saturnian satellite system and rings. did I mention some of the interesting features of the Saturnian satellite system and rings.

The only book in the series that survived intact (scientifically speaking) was Lucky Starr and the Pirates of the Asteroids. Lucky Starr and the Pirates of the Asteroids.

Fortunately, there was a way out. Honesty in the best policy and when the Lucky Starr series was reprinted in the 1970s, I insisted on inserting introductory notes explaining where the astronomical details had become outdated. At first, the publishers were a little reluctant to do so, but I explained that I could not allow the young reader to be misled, or, if he were knowledgeable, to have him think that I I was not. In went the notes, and, I am glad to say, sales were not adversely affected. was not. In went the notes, and, I am glad to say, sales were not adversely affected.

None of the stories in this collection was as badly shattered as my poor Lucky Starr books were, but there are things to beware of.

In the first place, there is one place where I missed something that was (in hindsight) very obvious, and I have been kicking myself over it for the last couple of years.

In "The Martian Way," the same story in which I triumphed with my description of the s.p.a.cewalk, I had my heroes approach Saturn and actually enter the ring system. In doing so I very carefully described the rings, making use of observations from Earth's surface to do so.

Now, from Earth's surface, some 800 million miles from Saturn, we see the rings as solid and unbroken except for the black line of the Ca.s.sini division that seems to separate them into two rings. The portion of the rings closest to Saturn is considerably dimmer than the rest of the ring system, and that portion is usually considered a third ring (the so-called "crepe ring.") And that was how I described the rings as seen by my s.p.a.ce-travelers in the story.

Yet it stands to reason (at least, now now it stands to reason) that if we could see the ring system from a nearer distance, we would see greater detail. We would see divisions-places where fewer particles were in orbit so that we would see dimmer lines separating brighter lines-divisions that would simply not be seen at great distances. Earth's surface telescopes would just blur them out and record only the thickest of the dim lines-the Ca.s.sini division. it stands to reason) that if we could see the ring system from a nearer distance, we would see greater detail. We would see divisions-places where fewer particles were in orbit so that we would see dimmer lines separating brighter lines-divisions that would simply not be seen at great distances. Earth's surface telescopes would just blur them out and record only the thickest of the dim lines-the Ca.s.sini division.

The closer we would get, the more numerous and the thinner the bright lines would get as visibility became clearer and clearer, until, when we were as close as we could get and still see all the rings, the rings would look like a grooved record-which is what they do do look like. look like.

Suppose I had figured this out in 1952 and had described the rings in that fas.h.i.+on. Even if I had missed such things as shadowy "spokes" in the ring, and "braided" rings, things that were absolutely unpredictable, it would have been great if I had imagined the fine divisions. That was an easy deduction to make and if I had described the rings in that fas.h.i.+on then, as soon as those rings had been probed I would have announced that I had antic.i.p.ated what they had discovered. (You think that modesty would have held me back? Don't be an idiot!) How great that would have been! As it is, my failure to see this marks me down as not very bright, and that is there, for all to see, in "The Martian Way." To be sure, no astronomer saw the truth about the rings in 1952, but what of that? An astronomer is only an astronomer and his vision is naturally limited. I am a science fiction writer science fiction writer and more is expected of me. and more is expected of me.

Then, too, sometimes when I saw accurately, or when I saw something that might well prove to be accurate some day, then I generally placed it far too far into the future. I admit I got the robots correct, for my earliest stories indicated that they got their start in the 1980s and 1990s, which is not bad at all.

However, what of the computerized cars in "Sally" and of the pocket computers in "The Feeling of Power"? I was careful not to give the exact dates of discovery of these advances. (I may be dumb, but I'm not that that dumb.) Still, there's no doubt as we read the stories that they are discoveries of the far future-yet they're here dumb.) Still, there's no doubt as we read the stories that they are discoveries of the far future-yet they're here now now and I have lived to see them, and be embarra.s.sed over my lack of confidence in the human mind and human ingenuity. and I have lived to see them, and be embarra.s.sed over my lack of confidence in the human mind and human ingenuity.

"Breeds There a Man...?" deals, in part, with the development of an advance against the nuclear bomb. It was published in 1951 and, although I don't date it, the impression it gives is that its events take place in the near future, perhaps just a few years after 1951.

I was clearly wrong in this, for real discussions of possible defenses didn't come till the 1980s.

What's more, my notion of a defense was a purely static one-the creation of a force-field s.h.i.+eld strong enough to resist even a nuclear explosion (the story was written before the H-Bomb was invented, by the way). Now that we are are considering a nuclear defense, we are talking of an active one. We are talking of the use of computerized X-ray lasers, designed to shoot down intercontinental ballistic missiles as soon as they are launched and move beyond the atmosphere. Frankly, I don't think this will work either, but it is considerably more advanced than my own foolish speculation of the matter in 1951, thirty-five years ago. considering a nuclear defense, we are talking of an active one. We are talking of the use of computerized X-ray lasers, designed to shoot down intercontinental ballistic missiles as soon as they are launched and move beyond the atmosphere. Frankly, I don't think this will work either, but it is considerably more advanced than my own foolish speculation of the matter in 1951, thirty-five years ago.

Generally, I can do my best foreseeing once I'm given a hint (a good strong hint). In my robot stories, I postulated robots that were so huge that they were immobile and that could do nothing but think and communicate the results of those thoughts. I had one like that in my very first robot story. In later robot stories I called them "brains." I didn't think to call them computers.

My robots, too, had "brains" that made them work, and I never spoke of them as computers, either. I had to make them science-fictionish, of course, so I called them "positronic brains." Positrons had been detected for the first time only four years before my first robot story had been written.

Positrons were exciting particles, bringing with them visions of "antimatter." For that reason, I thought positronic brains was a phrase that sounded good. They would not be essentially different from electronic brains, except that positrons could be made to come into being and would then be destroyed in a millionth of a second or so by all the electrons that surround them, no matter where on Earth they were. That gave me the notion that they might be seen as responsible for the rapidity of thought. To be sure, the energy relations.h.i.+ps-the energy required to produce positrons in quant.i.ty or the energy released when positrons are destroyed in quant.i.ty-are horrendous, so great that the notion of positronic brains is forever impossible, in all likelihood-but I ignored that.

It wasn't until after computers were invented and the public was made aware of their existence, that computers began to exist in my stories, and even then I didn't truly conceive of the possibility of miniaturization. Yes, I spoke of rocket computers but I visualized them as scarcely more powerful than a slide rule.

But eventually I did grasp miniaturization-naturally, after after the process had started. In "The Last Question" I began with my usual computer, Multivac, as large as a city, for I could only conceive a larger computer by imagining more and more vacuum tubes heaved into it. But then, in that story, I began miniaturizing and miniaturizing far beyond what I think there is any real possibility of. the process had started. In "The Last Question" I began with my usual computer, Multivac, as large as a city, for I could only conceive a larger computer by imagining more and more vacuum tubes heaved into it. But then, in that story, I began miniaturizing and miniaturizing far beyond what I think there is any real possibility of.

However, I suspect the readers are always ready to forgive a poor science fiction writer getting to be out-of-date. As I said, my "Lucky Starr" books were not hurt for being out-of-date. As a matter.of fact, H.G. Wells's The War of the Worlds The War of the Worlds is still read avidly, nearly a century after it was published and despite the incredibly false picture of Mars that it represents (false in the light of the Mars we know is still read avidly, nearly a century after it was published and despite the incredibly false picture of Mars that it represents (false in the light of the Mars we know today). today). The pictures of Mars given by Edgar Rice Burroughs, a generation after Wells, and by Ray Bradbury even as late as the 1950s, are also in no way comparable to the real thing, and yet that doesn't make it impossible to read The pictures of Mars given by Edgar Rice Burroughs, a generation after Wells, and by Ray Bradbury even as late as the 1950s, are also in no way comparable to the real thing, and yet that doesn't make it impossible to read A Princess on Mars A Princess on Mars or or The Martian Chronicles, The Martian Chronicles, either. either.

That is because there is more to a science fiction story than the science it contains. There is also the story story and if the science it contains is bent because of later discoveries, or because the plot absolutely demands the bending, we tend to forgive and overlook. and if the science it contains is bent because of later discoveries, or because the plot absolutely demands the bending, we tend to forgive and overlook.

For instance, in my story "The Billiard Ball" I have a billiard ball enter a region of s.p.a.ce in which it instantly a.s.sumes the speed of light. This is undoubtedly impossible, but even in terms of my bending of science, there is something more impossible. The billiard ball has a finite volume. Part of it enters the region first and that part instantly a.s.sumes the speed of light and breaks away from the rest. In short, the billiard ball must be reduced to atoms, or objects even less substantial, yet in the story it retains its integrity. My Conscience hurt me, but I just let it hurt and did what I had to do.

In "The Ugly Little Boy," I have a version of time travel and I firmly believe that time travel is impossible. However, I ignored that because the story is only tangentially about time travel. What it is really really about is love. about is love.

Again I doubt that human beings will ever become living energy vortexes, though I present them as such in "Eyes Do More Than See," Who cares? The story is really about the beauty of material things.

I think you see what I am getting at. You may, in reading the following stories, find points in science that are inaccurate in themselves, or that are made inaccurate by subsequent advance. But if you write to tell me about it, please tell me also if you enjoyed the story anyway. You might not, of course, but I hope you will.

One more thing. My story collections are usually unill.u.s.trated and this doesn't bother me, for I am not very visual. I am a wordman. Nevertheless, this collection is ill.u.s.trated by Ralph McQuarrie and I must admit it adds immeasurably to the beauty of the book and even adds to the sense of the stories, by placing the reader into the proper visual att.i.tude. The cover ill.u.s.tration, which inspired my story "Robot Dreams," written for this collection, is beautiful and humanizes a robot in a way I have never seen before. Perhaps none of this is terribly surprising, for Ralph is one of the best and most influential of all science fiction artists, having been involved with such blockbuster movies as "Star Wars" and "The Empire Strikes Back." In 1986 he won an Oscar for special effects for the film "Coc.o.o.n." I am so proud to have him part of this this book. book.

Little Lost Robot

Measures on Hyper Base had been taken in a sort of rattling fury - the muscular equivalent of a hysterical shriek.

To itemize them in order of both chronology and desperation, they were: All work on the Hyperatomic Drive through all the s.p.a.ce volume occupied by the Stations of the Twenty-Seventh Asteroidal Grouping came to a halt. All work on the Hyperatomic Drive through all the s.p.a.ce volume occupied by the Stations of the Twenty-Seventh Asteroidal Grouping came to a halt.

That entire volume of s.p.a.ce was nipped out of the System, practically speaking. No one entered without permission. No one left under any conditions. That entire volume of s.p.a.ce was nipped out of the System, practically speaking. No one entered without permission. No one left under any conditions.

By special government patrol s.h.i.+p, Drs. Susan Calvin and Peter Bogert, respectively Head Psychologist and Mathematical Director of United States Robot & Mechanical Men Corporation, were brought to Hyper Base. By special government patrol s.h.i.+p, Drs. Susan Calvin and Peter Bogert, respectively Head Psychologist and Mathematical Director of United States Robot & Mechanical Men Corporation, were brought to Hyper Base.

Susan Calvin had never left the surface of Earth before, and had no perceptible desire to leave it this time. In an age of Atomic Power and a clearly coming Hyperatomic Drive, she remained quietly provincial. So she was dissatisfied with her trip and unconvinced of the emergency, and every line of her plain, middle-aged face showed it clearly enough during her first dinner at Hyper Base.

Nor did Dr. Bogert's sleek paleness abandon a certain hangdog att.i.tude. Nor did Major-general Kallner, who headed the project, even once forget to maintain a hunted expression. In short, it was a grisly episode, that meal, and the little session of three that followed began in a gray, unhappy manner.

Kallner, with his baldness glistening, and his dress uniform oddly unsuited to the general mood, began with uneasy directness.

"This is a queer story to tell, sir, and madam. I want to thank you for coming on short notice and without a reason being given. We'll try to correct that now. We've lost a robot. Work has stopped and must must stop until such time as we locate it. So far we have failed, and we feel we need expert help." stop until such time as we locate it. So far we have failed, and we feel we need expert help."

Perhaps the general felt his predicament anticlimactic. He continued with a note of desperation, "I needn't tell you the importance of our work here. More than eighty percent of last year's appropriations for scientific research have gone to us"

"Why, we know that," said Bogert, agreeably. "U. S. Robots is receiving a generous rental fee for use of our robots."

Susan Calvin injected a blunt, vinegary note, "What makes a single robot so important to the project, and why hasn't it been located?"

The general turned his red face toward her and wet his lips quickly, "Why, in a manner of speaking we have have located it." Then, with near anguish, "Here, suppose I explain. As soon as the robot failed to report a state of emergency was declared, and all movement off Hyper Base stopped. A cargo vessel had landed the previous day and had delivered us two robots for our laboratories. It had sixty-two robots of the... uh... game type for s.h.i.+pment elsewhere. We are certain as to that figure. There is no question about it whatever." located it." Then, with near anguish, "Here, suppose I explain. As soon as the robot failed to report a state of emergency was declared, and all movement off Hyper Base stopped. A cargo vessel had landed the previous day and had delivered us two robots for our laboratories. It had sixty-two robots of the... uh... game type for s.h.i.+pment elsewhere. We are certain as to that figure. There is no question about it whatever."

"Yes? And the connection?"

"When our missing robot failed of location anywhere - I a.s.sure you we would have found a missing blade of gra.s.s if it had been there to find - we brainstormed ourselves into counting the robots left of the cargo s.h.i.+p. They have sixty-three now."

"So that the sixty-third, I take it, is the missing prodigal?" Dr. Calvin's eyes darkened.

"Yes, but we have no way of telling which is the sixty-third."

There was a dead silence while the electric clock chimed eleven times, and then the robopsychologist said, "Very peculiar," and the corners of her lips moved downward.

"Peter," she turned to her colleague with a trace of savagery, "what's wrong here? What kind of robots are they, using at Hyper Base?"

Dr. Bogert hesitated and smiled feebly, "It's been rather a matter of delicacy till now, Susan."

She spoke rapidly, "Yes, till till now. If there are sixty-three same-type robots, one of which is wanted and the ident.i.ty of which cannot be determined, why won't any of them do? What's the idea of all this? Why have we been sent for?" now. If there are sixty-three same-type robots, one of which is wanted and the ident.i.ty of which cannot be determined, why won't any of them do? What's the idea of all this? Why have we been sent for?"

Bogert said in resigned fas.h.i.+on, "If you'll give me a chance, Susan - Hyper Base happens to be using several robots whose brains are not impressioned with the entire First Law of Robotics."

"Aren't impressioned?" Calvin slumped back in her chair, "I see. How many were made?" impressioned?" Calvin slumped back in her chair, "I see. How many were made?"

"A few. It was on government order and there was no way of violating the secrecy. No one was to know except the top men directly concerned. You weren't included, Susan. It was nothing I had anything to do with."

The general interrupted with a measure of authority. "I would like to explain that bit. I hadn't been aware that Dr. Calvin was unacquainted with the situation. I needn't tell you, Dr. Calvin, that there always has been strong opposition to robots on the Planet. The only defense the government has had against the Fundamentalist radicals in this matter was the fact that robots are always built with an unbreakable First Law - which makes it impossible for them to harm human beings under any circ.u.mstance.

"But we had had to have robots of a different nature. So just a few of the NS-2 model, the Nestors, that is, were prepared with a modified First Law. To keep it quiet, all NS-2's are manufactured without serial numbers; modified members are delivered here along with a group of normal robots; and, of course, all our kind are under the strictest impressionment never to tell of their modification to unauthorized personnel." He wore an embarra.s.sed smile; "This has all worked out against us now." to have robots of a different nature. So just a few of the NS-2 model, the Nestors, that is, were prepared with a modified First Law. To keep it quiet, all NS-2's are manufactured without serial numbers; modified members are delivered here along with a group of normal robots; and, of course, all our kind are under the strictest impressionment never to tell of their modification to unauthorized personnel." He wore an embarra.s.sed smile; "This has all worked out against us now."

Calvin said grimly, "Have you asked each one who it is, anyhow? Certainly, you are authorized?"

The general nodded, "All sixty-three deny having worked here - and one is lying."

"Does the one you want show traces of wear? The others, I take it, are factory-fresh."

"The one in question only arrived last month. It, and the two that have just arrived, were to be the last we needed. There's no perceptible wear." He shook his head slowly and his eyes were haunted again, "Dr. Calvin, we don't dare let that s.h.i.+p leave. If the existence of non-First Law robots becomes general knowledge" There seemed no way of avoiding understatement in the conclusion.

"Destroy all sixty-three," said the robopsychologist coldly and flatly, "and make an end of it."

Bogert drew back a corner of his mouth. "You mean destroy thirty thousand dollars per robot. I'm afraid U. S. Robots wouldn't like that. We'd better make an effort first, Susan, before we destroy anything."

"In that case," she said, sharply, "I need facts. Exactly what advantage does Hyper Base derive from these modified robots? What factor made them desirable, general?"

Kallner ruffled his forehead and stroked it with an upward gesture of his hand. "We had trouble with our previous robots. Our men work with hard radiations a good deal, you see. It's dangerous, of course, but reasonable precautions are taken. There have been only two accidents since we began and neither was fatal. However, it was impossible to explain that to an ordinary robot. The First Law states - I'll quote it - 'No robot may harm a human being, or through inaction, allow a human being to come to harm.'

"That's primary, Dr. Calvin. When it was necessary for one of our men to expose himself for a short period to a moderate gamma field, one that would have no physiological effects, the nearest robot would dash in to drag him out. If the field were exceedingly weak, it would succeed, and work could not continue till all robots were cleared out. If the field were a trifle stronger, the robot would never reach the technician concerned, since its positronic brain would collapse under gamma radiations - and then we would be out one expensive and hard-to-replace robot.

"We tried arguing with them. Their point was that a human being in a gamma field was endangering his life and that it didn't matter that he could remain there half an hour safely. Supposing, they would say, he forgot and remained an hour. They couldn't take chances. We pointed out that they were risking their lives on a wild off-chance. But self-preservation is only the Third Law of Robotics - and the First Law of human safety came first. We gave them orders; we ordered them strictly and harshly to remain out of gamma fields at whatever cost. But obedience is only the Second Law of Robotics - and the First Law of human safety came first. Dr. Calvin, we either had to do without robots, or do something about the First Law - and we made our choice."

"I can't believe," said Dr. Calvin, "that it was found possible to remove the First Law."

"It wasn't removed, it was modified," explained Kallner. "Positronic brains were constructed that contained the positive aspect only of the Law, which in them reads: 'No robot may harm a human being.' That is all. They have no compulsion to prevent one coming to harm through an extraneous agency such as gamma rays. I state the matter correctly, Dr. Bogert?"

"Quite," a.s.sented the mathematician.

"And that is the only difference of your robots from the ordinary NS2 model? The only only difference? Peter?" difference? Peter?"

"The only only difference, Susan." difference, Susan."