Isaac Asimov & Positronic Brains

I’ve only read a handful of Asimov’s fiction, so I can’t really remember if his idea of a “Positronic Brain” was just something that sounded cool, or if he had some sort of deeper thought about it. What was it about anti-electrons that would make AI feasible to him?

Positrons were just discovered, and as I understand it positronic was just kind of a buzz word he used similar to the word “radioactive” in the '50s.

Yep, it was Asimov going for the rule of cool.

Ok, that’s what I kind of figured. But he was no slouch when it came to science, and seeing that he made such a big deal about Positronic Brains being the key to AI, I was hoping there was more thought behind it than just cherry-picking the flavor of the year in physics terms.


Asimov later cheerfully admitted that he chose the term because it was a new scientific term and that it meant nothing (the biggest problem with a positronic brain of any size would be to keep it from blowing up and destroying half the planet).

Asimov knew his science, but he also knew his storytelling. He wrote an entire novel, The Gods Themselves based upon a scientific error he once made.

I’d like to hear about that, given I’ll probably never get around to reading it. You might want to spoiler it if you are so kind as to respond.


According to Asimov himself –

Asimov accosts Robert Silverberg at a sci-fi convention for referring to a radioactive isotope (plutonium-186) that could not exist. He then tells Silverberg that to show him real ingenuity, he would write a story about it (leave it to a biochemist!). This story ended up as “The God’s Themselves.”

Interesting. Thanks.

An aside, the other day I was remembering that horrible movie Food of the Gods :slight_smile:

but the way you tell it, it was Silverberg who made the mistake?

Yes, as I recall it. The Good Doctor’s ego would never have allowed him to admit making a mistake about science.

Rays were cool even before then. The first Robot stories were written in the early 1940s, and Asimov wasn’t a nuclear physicist in any case. I don’t think chemists have much reason to muck with subatomic particles.

I remember an intro piece in one of Asimov’s books about a guy who was fairly big in sci fi in the early forties writing a story about a nuclear weapon, and getting a visit from the CIA because he got so much stuff right. (Turned out he really just did know that much about nuclear science, plus a sizeable dose of luck, no espionage involved.)

He not only wanted the term to sound cool by basing it on a new scientific term, but he needed it to be clear that these devices were fundamentally different from electronic computers. If they were like current devices, they could have been easily built without the Three Laws. Many of the stories hinged on the fact that the Three Laws are an unalterable feature of positronic brains. (Though he did write some with edited laws, with mostly unfortunate results for the characters.)

Asimov is credited by the OED with bringing us the adjective ‘positronic.’

Also the nouns robotics (which he thought was a real word at the time) and psychohistory, though obviously the latter is a lot less common.

Interestingly enough, the Three Laws are, to my knowledge, used in robotics quite frequently.

I do not see how that can be possible. Or is that just another MacGuffiny thing?

As I remember the Three Laws are “hard-wired” into the brain at manufacture.

Cleve Cartmill, and the story was Deadline. Not a big name at all. The CIA didn’t exist then, of course, and I think it was the FBI. Campbell convinced them that this kind of thing had been in sf for years, and calling attention to it by yanking the story would be worse than letting it run.

Far more interesting is Heinlein, who in “Solution Unsatisfactory!” predicted the nuclear standoff. The weapon was radioactive dust, not the bomb, but this shows once more his talent in seeing the sociological and political consequences of technology.

Yes, the idea was that the positronic brain was invented with the Three Laws hardwired in, and making any change to them was just as difficult as inventing the brain from scratch.

In the Caliban books, written in Asimov’s galaxy by Roger McBride Allen, new gravitonic brains were invented. They had the ability to edit or even delete laws. I’m certain Asimov insisted that Allen not be allowed to invent that feature for a positronic brain.

Yes. Removing the three laws from the positronic brains would make them inoperable; they were a part of everything they did.

The three laws were a safety feature deliberately created, not a natural consequence of positronics. It would have been perfectly possible to create a positronic brain without them, but they were afraid of the robots turning on their masters.