Well, let’s talk about the ordinary ones—not HAL—for now. It’s really fascinating what was predicted correctly there, and what wasn’t. There was one definite major conceptual mistake, I think, that had to do with misassessing the power of software, and that pervaded a lot of the things that weren’t got right.

One thing that was got very right is that computers would be important, and that there would be computers—or at least computer screens—everywhere. But the thing that was got wrong was how much stuff would have to be done with different special-purpose devices, and how much could be done just with software. There were fine in-flight TV screens on the shuttle. But they had rows of separate buttons underneath, not software menus. There were lots of separate computer screens showing different things. Not just software-controlled windows. People were looking at physical photographs of the monolith on the Moon, not computer renderings. And there was a click for the camera shutter. Not digital. And of course there were clipboards being used on Discovery.

Now, one can argue that airplane cockpits still have rows of buttons, and that the clipboard thing was just about not predicting portable computers. But I think there was more to it. I think Kubrick and Clarke didn’t have the idea that once you’re dealing with a general-purpose computer, you can do things purely in software, without having to have different special-purpose hardware.

I certainly don’t blame Kubrick and Clarke for making the mistake. In fact, people often still make the same mistake today. But if one looks at the history of computing there’s an extremely clear trend: special-purpose hardware gets replaced by software running on general-purpose machines. One doesn’t need physical teletypes anymore, because the forms of letters can be made in software. Soon one won’t need video hardware, because all the signal processing will be able to be done in software. People often don’t see it, but universal computers really are universal. And it’s only a matter of time before pure software can do more and more things. Without needing special hardware stuff.

It’s funny. Watching 2001 really makes me think about the significance of universal computing and software. 2001 in a sense makes the case that it was the invention of tools that really got humans started on the path to where they are today. Well, I guess in the last few years I’ve come to think that the invention of software is something of about the same magnitude as the invention of tools. You see, before you have tools, the only device for getting things done is your own body. But with tools, you can go beyond that. Still, once you’ve built a tool, you’re stuck with that particular tool. The idea of a universal computer is that you can make a universal tool—a general-purpose object—that you can program to do absolutely anything. And I think now that we’ve only just started down the path that’s opened up by the idea of software. There’s probably as much development to come as in the sequence in 2001 that cuts from a bone as bashing tool to an orbiting spacecraft.