Hey, I'm not a particle physicist, but I've read a bunch of books by people who think the universe is a computer. (Three Scientists and Their Gods, A New Kind Of Science, and The Recursive Universe (this last is out of print and much better than Wolfram's newer but more turgid ANKOS.)

I don't think the universe is a computer either, but I don't think this guy understands what that would mean anyway.

From the article: "I just find it obvious that pretty much by definition, discrete objects are always less fundamental and less complete than the continuous ones. A discrete description of some object or phenomenon is always an approximation."

Now the whole thrust of the "computer-universe-ism" people's argument, if I read them correctly, is that the universe is really a discrete structure, in which case a discrete model of said structure would not be ANY kind of approximation. I.e. to what are the integers (a discrete structure) a (supposedly poor) approximation? What about the two-element set {0,1} or (say) groups? (The group theory bit is a trick for the author.)

We'd better leave these questions to be answered by empirical data---or if we need philosophers to chime in, better ones than this.