I recently read James Gleick’s book Information: a history, a theory, a flood. It’s a fascinating account of our varying relationships to information. For a long time, we were only set on getting as much of it as we could; then a theory of information developed in the 20th century (principally by Claude Shannon); and now we are drowning in the stuff. But the question that has been bothering me is : what is it?
It’s not that Gleick ignores the question. It’s just that he’s a journalist, and so his aim is to tell a string of interesting stories. Along the way he mentions the physicist John Wheeler’s view that, ultimately, information is the stuff of the universe – in a slogan, “It from Bit.” But what could it possibly mean to say that everything is composed of information? I can understand a hunk of matter or energy or a field somehow having information. Stuff can have a structure which allows us to extract information from it. But what could it possibly mean for the stuff to be information?
So what is information? I’ve gone from reading Gleick’s book to reading Greene’s The Hidden Reality, which also discusses the idea, and supports Gleick’s account that Wheeler thought information may be everything. There’s a lot more studying I need to do, but right now it seems to me that there are two ways of understanding information. The first is purely objective, having to do with being able to quantify and summarize a thing’s structure, regardless of its usefulness for human beings. On this account, the harder it is to exactly summarize an entity’s features, and transmit it exactly to someone else, the less information it contains. So an unending sequence of “01234567890123456789…” doesn’t contain a lot of information, since even though the sequence is infinite, it can be fully summarized as “0123456789, repeat without end.” On the other hand, a random sequence like “73885629199…” is packed with information, since you can’t adequately summarize its exact features without actually giving it. But this view seems counter-intuitive. Consider this message:
“It is a truth that the group identified as the enemy will in the future do something that can be accurately described as attacking at a time that can be described in complete accuracy as dawn.”
That, according to this first view, contains a lot more information than “The enemy will attack at dawn,” since you would have to transmit a longer sequence in order for another person to reproduce it accurately. Wrong.
The second way of looking at information requires humans to enter the picture and sort out what’s useful and relevant or interesting from what isn’t. In this case, the sequence “314159265…” has a lot more information than our earlier “73885629199…”, since it describes pi, while the second sequence isn’t useful for anything. But bringing in subjective human evaluations sort of makes the science of information less sciency.
Also entering into this mess is the notion of entropy, or lack of order, which also seems to me to draw upon both objective and subjective measures. But I’ve read enough now to believe that I really don’t know what I’m talking about. I need to read more, and some other books are on their way to me.
OK, now that I’ve admitted I don’t really know what information is, what could it mean to say that everything is made of it? Here’s the best stab I have at it, courtesy of Greene’s book. Imagine making a computer simulation of the universe. This simulation would have to include a representation of you doing what you are doing now. That virtual you, in the program, and the virtual everything surrounding that virtual you, exists in the computer program. That is to say that the virtual you and the virtual everything are ultimately bits of information – perhaps being processed by some physical, colossal supercomputer, but that isn’t relevant, since information isn’t tied to particular structures, and nothing would be different in the virtual world if it were running on some other kind of system. It’s the data, and the processing of the data that counts. Now if you really are the virtual you, and everything around you is the virtual everything, then indeed everything is composed of information.
Sounds loopy, but apparently that is one of the ideas being bandied about by those crazy physicists. It is impossible for me to think about any of this without going back to Aristotle, and his account of form. He didn’t go so far as to say that everything is form, but he knew it was what we need to focus on when we want to understand things; the underlying stuff or matter doesn’t really matter much, except as a carrier of form. I’m surprised, sort of, that neither Gleick nor Greene make anything of this. But only “sort of” surprised, since they’re anxious to point out how new all of this is.