Is the Universe Actually Made of Math?

From what I can tell, this is just a restatement of The Anthropic Principle, which itself is not a theory, but a trivial answer to a trivial philosophical question. He says we can make "all kinds of predictions", but I wonder if he has ever made even one.

I'm reminded of Greg Egan's "running on the dust" theory. The main idea is the same: if a simulation algorithm describes our universe, there's no need for a machine to run the simulation. We exist... in the abstract, in the same sense as numbers exist.

I haven't read this guy's work but this interview makes it sound pretty ridiculous. First, he just ignores the bohmian and GRW interpretations of QM that are very popular right now. Next, he seems to ignore interpretations like many-minds because "physicists agree that there's an external reality" which is presumably similar to what we see, and not actually in a big superposition. So for the sake of according with physicists' intuitions, he posits various hierarchies of physical worlds. And then, it turns out that these worlds are actually made out of "math," whatever that means, but which certainly doesn't accord with physicists' intuitions. So what's the point? The other theories on offer are far simpler than this bait-n-switch.

"Made of math" means more or less I think "metric" in the sense of topologies.

So fudamentally, the simplest universe you could think of would be in a set of related topologies without defined metrics.

Then going up from there you get into more complex metrics, like say, Einstein's Reimann metric, and the like.

Perhaps our world has a metric of 26 dimensions like in string theory.

Anyway, as near as I can tell, Tegmark's "made of math" idea effectively means all topologies and metrics exist eternally, we happen to live on one of these metrics, or more precisely, upon one of the metrics in which self-aware substructures like us could exist.

Anyway, makes as much sense to me for a theory of everything, as for example, positing the "Intelligent Design by the Flying Sphaghetti Monster" being shoved down the throats of children these days!! :-)