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But that's
only half the story. The other half of the story, its complementary
half, is the story about information. In one way you can think about
what's going on in the world as energy, stuff moving around, bouncing
off each other — that's the way people have thought about the world
for over 400 years, since Galileo and Newton. But what was missing from
that picture was what that stuff was doing: how, why, what? These are
questions about information. What is going on? It's a question about
information being processed. Thinking about the world in terms of information
is complementary to thinking about it in terms of energy. The first physicists studying these problems were scientists who happened to be physicists, and the first person who was clearly aware of the connection between information, entropy, and physical mechanics and energy like quanta was Maxwell. Maxwell, in the 1850s and 60s, was the first person to write down formulas that related what we would now call information — ideas of information — to things like energy and entropy. He was also the first person to make such an explicit connection. He also had this wonderfully evocative far-out, William Gibsonesque notion of a demon. "Maxwell's Demon" is this hypothetical being that was able to look very closely at the molecules of gas whipping around in a room, and then rearrange them. Maxwell even came up with a model in which the demon was sitting at a partition, a tiny door, between two rooms and he could open and shut this door very rapidly. If he saw fast molecules coming from the right and slow molecules coming from the left, then he'd open the door and let the fast molecules go in the lefthand side, and let the slow molecules go into the righthand side. And since Maxwell already knew about this connection between the average speed of molecules and entropy, and he also knew that entropy had something to do with the total number of configurations, the total number of states a system can have, he pointed out, that if the demon continues to do this, the stuff on the lefthand side will get hot, and the stuff on the righthand side will get cold, because the molecules over on the left are fast, and the molecules on the right are slow. He also pointed out that there is something screwy about this because the demon is doing something that shouldn't take a lot of effort since the door can be as light as you want, the demon can be as small as you want, the amount of energy you use to open and shut the door can be as small as you desire, and yet somehow the demon is managing to make something hot on one side. Maxwell pointed out that this was in violation of all the laws of thermodynamics — in particular the second law of thermodynamics which says that if you've got a hot thing over here and a cold thing over there, then heat flows from the hot thing to the cold thing, and the hot thing gets cooler and the cold thing gets hotter, until eventually they end up the same temperature. And it never happens the opposite way. You never see something that's all the same temperature spontaneously. Maxwell pointed out that there was something funny going on, that there was this connection between entropy and this demon who was capable of processing information. To put it all in perspective, as far as I can tell, the main thing that separates humanity from most other living things, is the way that we deal with information. Somewhere along the line we developed methods, sophisticated mechanisms, for communicating via speech. Somewhere along the line we developed natural language, which is a universal method for processing information. Anything that you can imagine is processed with information and anything that could be said, can be said using language. That probably happened around a hundred thousand years ago, and since then, the history of human beings has been the development of ever more sophisticated ways of registering, processing, transforming, and dealing with information. Society through this methodology creates an organizational formula that is totally wild compared with the organizational structures of most other species, which makes the human species distinctive, if there is something at all that makes us distinctive. In some sense we're just like any ordinary species out there. The extent to which we are different has to do with having more sophisticated methods for processing information. Something else has happened with computers. What's happened with society right now is that we have created these devices, computers, which already can register and process huge amounts of information, which is a significant fraction of the amount of information that human beings themselves, as a species, can process. When I think of all the information being processed there, all the information being communicated back and forth over the Internet, or even just all the information that you and I can communicate back and forth by talking, I start to look at the total amount of information being processed by human beings — and their artifacts — we are at a very interesting point of human history, which is at the stage where our artifacts will soon be processing more information than we physically will be able to process. So I have to ask, how many bits am I processing per second in my head? I could estimate it, it's going to be around ten billion neurons, something like 10 to the 15 bits per second, around a million billion bits per second. Hell if I know what it all means — we're going to find out. That's the great thing. We're going to be around to find out some of what this means. If you think that information processing is where the action is, it may mean in fact that human beings are not going to be where the action is anymore. On the other hand, given that we are the people who created the devices that are doing this mass of information processing, we, as a species, are uniquely poised to make our lives interesting and fun in completely unforeseen ways. Every physical system, just by existing, can register information. And every physical system, just by evolving according to its own peculiar dynamics, can process that information. I'm interested in how the world registers information and how it processes it. Of course, one way of thinking about all of life and civilization is as being about how the world registers and processes information. Certainly that's what sex is about; that's what history is about. But since I'm a scientist who deals with the physics of how things process information, I'm actually interested in that notion in a more specific way. I want to figure out not only how the world processes information, but how much information it's processing. I've recently been working on methods to assign numerical values to how much information is being processed, just by ordinary physical dynamics. This is very exciting for me, because I've been working in this field for a long time trying to come up with mathematical techniques for characterizing how things process information, and how much information they're processing.
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