A Subjective Assessment of
Fred Dretske's Information Theory:
I Don't Feel Like Going Into It
If You Want to Know the Truth

by Holden Caulfield


If you really want to hear about it, the first thing you'll probably want to know is what Dretske's concept of information is, and what he was defining, and what sort of criteria for knowledge and all he used, and all that epistemological kind of crap, but I don't feel like going into it, if you want to know the truth. In the first place, the theory wasn't all that interesting, and in the second place, once you've spent six months on something like that you sorta want to get it all behind you and think about something else. I'll just tell you about this madman chapter on the Communication Channel and how Dretske makes this very sad attempt at refuting skepticism.

Where I want to start telling is Dretske's discussion of absolute concepts. He starts off saying that knowledge doesn't admit of degrees, that you either know something or you don't. He gives this example about a crumby red ball, and how if we both know the ball is red it doesn't make any sense to say that one of us knows it's red better than the other. That killed me. I can just see these two crazy bastards arguing about this lousy ball in some little room that smells like someone just took a leak in the corner.

Anyway, after Dretske rambles on about this goddam ball for a while he tells about this guy Peter Unger and how he says that not many things are really flat, on account of there's always going to be bumps or irregularities on the lousy surface. Even if something looks flat, it's not going to be if you look at it through a goddaam microscope or something. Old Unger goes on to say that since knowledge is an absolute concept like flatness, nothing is really known. Well, Dretske wasn't too crazy about that a idea on account of its skeptical conclusions and all, so he comes up with this lousy notion that while nothing can be flat if it has any crumby bumps, what counts as a bump depends on the surface being described. Like having dust in your pocket doesn't count when you say it's empty and all, for Chrissakes.

So he gets through telling that gorgeous bit, about how what counts as a bump is relative and all, and you can tell he thinks he's this really neat guy. I mean, I can see this Dretske bastard sitting there in this very sad, ratty old jacket that he was probably born in or something, giving Unger this icy look like he's just beaten the hell out of him in ping-pong or something. No kidding.

Anyway, Dretske starts telling about what he calls Channel Conditions, and how you have to distinguish between the information about a source a signal carries and the channel on which the delivery of the information depends. That killed me. He gets into this big-ass discussion about voltmeters and equivocation to prove his crumby point, and how a channel of information either generates no relevant information or generates only redundant information. That's why a signal carries information about the source only, and not the lousy channel. Very big deal.

The thing is, Dretske keeps emphasizing relevant possible alternatives; that something counts as a channel only if it lacks a "genuine" or "relevant" alternative possibility. It was getting kind of nauseating on account of he never really tells you what constitutes a relevant possibility, or when a condition has genuine alternative states. No kidding.

It's not that he doesn't try. He makes this very sad attempt and all, but the best the poor bastard can do it say that you can't count things liked Descartes' Evil Demon or supernatural intervention as being genuine possibilities, on account of every signal would be equivocal and no one would know anything, for Chrissakes. You can tell not knowing really drives old Dretske crazy. He starts telling how his lousy communication theory takes what does or doesn't happen over a long time as a guide or something for what can or can't happen. That killed me.

The thing is, you know Dretske thinks he's this witty bastard because he keeps on about how a communication channel is "innocent until proven guilty", and then gives this very sad example of some guy named Elmer and whether or not it's a real possibility for him to be hallucinating french fries on his dinner plate and all, just because some other crazy bastards might have. He was some little cheerer upper. I can just see old Dretske in a faculty meeting or something, sitting in this vomity-looking chair trying to say a lot of witty things to break the mood. I wouldn't be too crazy about being in the same room with him, if you want to know the truth.

Anyway, he really has this relevant possibility thing on the old brain, because he ends the lousy chapter still harping about it. No kidding.

That's all I'm going to tell about. I could probably tell you about analog and digital coding, or Dretske's concept of information and all, but I don't feel like it. I really don't. That stuff doesn't interest me too much right now.

I guess you're wondering what I think about all this stuff I just finished telling you about. I don't know what the hell to say. If you want to know the truth, I don't know what to think about it. Goddam theories. They always end up making you confused as hell.


With apologies to J.D. Salinger


1. Dretske, F. (1981). Knowledge and the Flow of Information. Cambridge, Massachusetts: MIT Press.

2. Salinger, J.D. (1951). The Catcher in the Rye. New York: Bantam Books.





1990-2007 JASM