But maybe, one might think, HAL could at least be given some overall directives—like be nice to humans, or other potential principles of AI ethics. But here’s the problem: given any precise specification, it’s inevitable that there will unintended consequences. One might says these are bugs in the specification, but the problem is they’re inevitable. When computational irreducibility is present, there’s basically never any finite specification that can avoid any conceivable unintended consequence.

Or, said in terms of 2001, it’s inevitable that HAL will be capable of exhibiting unexpected behavior. It’s just a consequence of being a system that does sophisticated computation. It lets HAL show creativity and take initiative. But it also means HAL’s behavior can’t ever be completely predicted.

The basic theoretical underpinnings to know this already existed in the 1950s or even earlier. But it took experience with actual complex computer systems in the 1970s and 1980s for intuition about bugs to develop. And it took my explorations of the computational universe in the 1980s and 1990s to make it clear how ubiquitous the phenomenon of computational irreducibility actually is, and how much it affects basically any sufficiently broad specification.

How Did They Get It Right?

It’s interesting to see what the makers of 2001 got wrong about the future, but it’s impressive how much they got right. So how did they do it? Well, between Stanley Kubrick and Arthur C. Clarke (and their scientific consultant Fred Ordway III), they solicited input from a fair fraction of the top technology companies of the day—and (though there’s nothing in the movie credits about them) received a surprising amount of detailed information about the plans and aspirations of these companies, along with quite a few designs custom-made for the movie as a kind of product placement.

In the very first space scene in the movie, for example, one sees an assortment of differently shaped spacecraft, that were based on concept designs from the likes of Boeing, Grumman and General Dynamics, as well as NASA. (In the movie, there are no aerospace manufacturer logos—and NASA also doesn’t get a mention; instead the assorted spacecraft carry the flags of various countries.)

But so where did the notion of having an intelligent computer come from? I don’t think it had an external source. I think it was just an idea that was very much in the air at the time. My late friend Marvin Minsky, who was one of the pioneers of AI in the 1960s, visited the set of 2001 its filming. But Kubrick apparently didn’t ask him about AI; instead he asked about things like computer graphics, the naturalness of computer voices, and robotics. (Marvin claims to have suggested the configuration of arms that was used for the pods on the Jupiter spacecraft.)

But what about the details of HAL? Where did those come from? The answer is that they came from IBM.

IBM was at the time by far the world’s largest computer company, and it also conveniently happened to be headquartered in New York City, which is where Kubrick and Clarke were doing their work. IBM—as now—was always working on advanced concepts that they could demo. They worked on voice recognition. They worked on image recognition. They worked on computer chess. In fact, they worked on pretty much all the specific technical features of HAL shown in 2001. Many of these features are even shown in the "Information Machine" movie IBM made for the 1964 World’s Fair in New York City (though, curiously, that movie has a dynamic multi-window form of presentation that wasn’t adopted for HAL).

In 1964, IBM had proudly introduced their System/360 mainframe computers. And the rhetoric about HAL having a flawless operational record could almost be out of IBM’s marketing material for the 360. And of course HAL was physically big—like a mainframe computer (actually even big enough that a person could go inside the computer). But there was one thing about HAL that was very non-IBM. Back then, IBM always strenuously avoided ever saying that computers could themselves be smart; they just emphasized that computers would do what people told them to. (Somewhat ironically, the internal slogan that IBM used for its employees was "Think." It took until the 1980s for IBM to start talking about computers as smart—and for example in 1980 when my friend Greg Chaitin was advising the then-head of research at IBM he was told it was deliberate policy not to pursue AI, because IBM didn’t want its human customers to fear they might be replaced by AIs.)