There is a general myth among laymen that, somehow, the chief function of a science fiction writer is to make predictions that eventually come true.

Thus, I am frequently asked, "How does it feel to see all the predictions you have made coming true?"

To which I can only reply, "It feels great-in those very few cases in which something I have said actually came to pass."

At other times, I am asked with utter confidence, "Can you give us a few of your predictions that have come true?"

I would love to be able to say, "Well, to name just a few: airplanes, radios, television, skyscrapers, and, in my early days, the wheel and fire."

But I can't bring myself to do that. The interviewers might actually print it, and they might try to give me a medal for predicting fire.

However, I came across a prediction I made once that I didn't know I had made-that actually I didn't know was a prediction. Nor did I discover it myself. Someone pointed it out to me.

In order to explain this, I'll have to take the long way round. Please bear with me.

Back in 1952, I began to write a novel called The Caves of Steel. It was finished in 1953, was published in the October, November, and December 1953, issues of Galaxy as a three-part serial, and was published in book form by Doubleday in 1954.

It was a science fiction murder mystery that introduced my characters Elijah Baley and R. Daneel

Olivaw, whom some of you may have come across in your reading. Toward the end of The Caves of Steel, I needed a second murder for the sake of the plot, and that bothered me, for I don't like murders and I rarely have them in my mysteries. When I do, there is only one and it is committed offstage, usually before the story begins. (I'm funny that way.)

The first murder in The Caves of Steel had been offstage before the story began, and the second murder would be offstage, also, but I didn't want to kill a human being, so, instead, I killed a rather simple robot. But, again, I didn't want to kill him brutally by smashing in his cranium or throwing him into a vat of melted lead. I preferred something more science fictional.

So here is a character in the story, a Dr. Gerrigel, describing the dead robot:

"'In the robot's partly clenched right fist,' said Dr. Gerrigel, 'was a shiny ovoid about two inches long and half an inch wide with a mica window at one end. The fist was in contact with his skull as though the robot's last act had been to touch his head. The thing he was holding was an alpha-sprayer. You know what they are, I suppose?"'

The nature of the alpha-sprayer was then explained for the sake of the reader. It was described as a device that sends out a beam of alpha particles through the mica window. The impingement of the alpha particles on the robot's positronic brain was drastic. Or, as I put it: "Dr. Gerrigel said, 'Yes, and his positronic brain paths were immediately randomized. Instant death, so to speak."'

Well, why not? Alpha particles are capable of knocking electrons out of atoms. It is because they do so, leaving electrically charged ions behind, that it was discovered, in 1911, that they could be detected in cloud chambers. The ions, with their electric charge, served as nuclei for tiny water droplets and those droplets marked out the path of the particle.

Positrons, which I use in robotic brain paths in order to make them sound science fictional, are precisely like electrons except for possessing a positive charge rather than a negative one. Alpha particles should shove them out of the way with equal ease, and if positrons make up the brain paths, shoving them away disrupts the brain paths and inactivates the robots.

There's nothing ingenious about it at all. Perfectly humdrum.

And then a short time ago, I received a letter from a gentleman working with a corporation that deals with computers. It begins as follows:

"This letter is to inform you and congratulate you on another remarkable scientific prediction of the future; namely your foreseeing of the dynamic random-access memory (DRAM) logic upset problem caused by alpha particle emission, first observed in 1977, but written about by you in Caves of Steel in 1957." [Note: Actually, 1952.]

Apparently the corporation tracked down failures in memory devices and finally decided that:

"These failures are caused by trace amounts of radioactive elements present in the packaging material used to encapsulate the silicon devices which, upon radioactive decay, emit high energy alpha particles that upset the logic states of the semiconductor memory......

"I am writing you about this topic because in your book, Caves of Steel, published in the 1950s, you use an alpha particle emitter to 'murder' one of the robots in the story, by destroying ('randomizing') its positronic brain. This is, of course, as good a way of describing a logic upset as any I've heard.

"I get a great big kick out of finding out that our millions of dollars of research, culminating in several international awards for the most important scientific contribution in the field of reliability of semiconductor devices in 1978 and 1979, was predicted in substantially accurate form twenty years [Note: twenty-five years, actually] before the events took place! You may certainly with great pride add this phenomenon to your collection of scientific predictions."

Well, you can easily imagine that I was delighted, but truth is mighty and will prevail. I instantly wrote to the gentleman who was so pleased at my prediction that I honestly was not aware that I was making a prediction, and that the whole thing was a tribute, not to my ingenuity, but to the good luck that constantly dogs my footsteps.

A much more intuitive and remarkable prediction was made by the science-fictional father of us all, H. G. Wells. First, a little background.

In 1913, the British chemist Frederick Soddy (1877-1956), advanced the "isotope concept" based on his studies of the elements produced in the course of radioactive decay. He proposed that a particular element might be made up of atoms identical in chemical properties but differing somewhat in atomic weight. Elements, then, instead of necessarily being made up of absolutely identical elements were actually mixtures of several almost identical "isotopes" differing in atomic weight.

This made so much sense, it was quickly accepted and has remained a cornerstone of chemistry and of atomic physics ever since.

But just the other day, I received a reprint of a paper by H. G. Wells, written on September 5,1896 (seventeen years before Soddy's suggestion), in which he refers to some work done by a chemist the previous year, before radioactivity had even been discovered, and suggests that to explain that work, it is possible to suppose that "there are two kinds of oxygen, one with an atom a little heavier than the other." By saying that, he is anticipating and predicting the existence of isotopes.

Furthermore, he points out that "the electric spark traversing the gas has a...selective action. Your heavier atoms or molecules get driven this or that way with slightly more force." This is a pretty good description of a phenomenon first noted by the British physicist Joseph John Thomson (1856-1940), in 1912, sixteen years after Wells's suggestion.

How's that!

Naturally, I would like to point to something of my own that contained a bit of nice intuitive insight, and here it is. In 1966, I wrote a scientific essay, "I'm Looking Over a Four-Leaf Clover," which eventually appeared in the September 1966 issue of The Magazine of Fantasy and Science Fiction.

In it I wanted to speculate about the origin of the universe and I was anxious to rebut the favorite comment of some who would ask, "If the universe started as a 'cosmic egg,' where did the cosmic egg come from?" The hope was that if I were faced with that question I would have to admit the existence of a supernatural agency of creation.

I therefore postulated the existence of "negative energy" and supposed that energy was created in both negative and positive form so that there was no net creation. I went on to advance what I called "

Asimov's Cosmogonic Principle" and wrote, "The most economical way of expressing the principle is 'In the Beginning, there was Nothing.'"

Well, some ten years later, the theory of the "inflationary universe" was advanced. It was altogether different from anything I had suggested, but in one respect it was identical. The universe was pictured as starting as a quantum fluctuation in a vacuum, so that "In the Beginning, there was Nothing."

That piece of insight I am really proud of.