I wrote my first robot story, "Robbie," in May of 1939, when I was only nineteen years old.
What made it different from robot stories that had been written earlier was that I was determined not to make my robots symbols. They were not to be symbols of humanity's overweening arrogance. They were not to be examples of human ambitions trespassing on the domain of the Almighty. They were not to be a new Tower of Babel requiring punishment.
Nor were the robots to be symbols of minority groups. They were not to be pathetic creatures that were unfairly persecuted so that I could make Aesopic statements about Jews, Blacks or any other mistreated members of society. Naturally, I was bitterly opposed to such mistreatment and I made that plain in numerous stories and essays-but not in my robot stories.
In that case, what did I make my robots?-I made them engineering devices. I made them tools. I made them machines to serve human ends. And I made them objects with built-in safety features. In other words, I set it up so that a robot could not kill his creator, and having outlawed that heavily overused plot, I was free to consider other, more rational consequences.
Since I began writing my robot stories in 1939, I did not mention computerization in their connection. The electronic computer had not yet been invented and I did not foresee it. I did foresee, however, that the brain had to be electronic in some fashion. However, "electronic" didn't seem futuristic enough. The positron-a subatomic particle exactly like the electron but of opposite electric charge-had been discovered only four years before I wrote my first robot story. It sounded very science fictional indeed, so I gave my robots "positronic brains" and imagined their thoughts to consist of flashing streams of positrons, coming into existence, then going out of existence almost immediately. These stories that I wrote were therefore called "the positronic robot series," but there was no greater significance than what I have just described to the use of positrons rather than electrons.
At first, I did not bother actually systematizing, or putting into words, just what the safeguards were that I imagined to be built into my robots. From the very start, though, since I wasn't going to have it possible for a robot to kill its creator, I had to stress that robots could not harm human beings; that this was an ingrained part of the makeup of their positronic brains.
Thus, in the very first printed version of "Robbie," I had a character refer to a robot as follows: "He just can't help being faithful and loving and kind. He's a machine, made so."
After writing "Robbie," which John Campbell, of Astounding Science Fiction, rejected, I went on to other robot stories which Campbell accepted. On December 23, 1940, I came to him with an idea for a mind-reading robot (which later became "Liar!") and John was dissatisfied with my explanations of why the robot behaved as it did. He wanted the safeguard specified precisely so that we could understand the robot. Together, then, we worked out what came to be known as the "Three Laws of Robotics. " The concept was mine, for it was obtained out of the stories I had already written, but the actual wording (if I remember correctly) was beaten out then and there by the two of us.
The Three Laws were logical and made sense. To begin with, there was the question of safety, which had been foremost in my mind when I began to write stories about my robots. What's more I was aware of the fact that even without actively attempting to do harm, one could quietly, by doing nothing, allow harm to come. What was in my mind was Arthur Hugh Clough's cynical "The Latest Decalog," in which the Ten Commandments ate rewritten in deeply satirical Machiavellian fashion. The one item most frequently quoted is: "Thou shalt not kill, but needst not strive / Officiously to keep alive."
For that reason I insisted that the First Law (safety) had to be in two parts and it came out this way: