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.
99% of this "profound" bullshit has been covered and recovered for hundreds of years by various philosophers and scientists. Get yourself an introduction to philosophy book of some sort and it will clearly lay out some of the most popular and lasting arguments.
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.
Well, I say we exist in the non-abstract. Or don't exist in the abstract. Or non-abstract. Or whatever. A radically different "view", and yet the implications are the same (non-existent, that is).
This isn't too far removed from arguing about whether the Holy Ghost is indeed the same entity as God the Father.
You are right that it doesn't offer any concrete predictions at the moment and perhaps it never will. But if everybody dismissed notions just because they couldn't immediately see what they could be used for we'd live in a pretty boring and backwards world.
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.
First, he just ignores ....very popular right now. Next, he seems to ignore..... many-minds because "physicists agree that there's an external reality" ... So for the sake of according with physicists' intuitions,.... doesn't accord with physicists' intuitions
You should applaud him. To discover or innovate you must "ignore" and make "no assumptions" nor "judgements" only make "observations". Only a very few people do this and sadly that is why most discoveries and breakthrough are made by accident.
Right... but you shouldn't ignore something that posits fewer entities than your theory yet has the same explanatory power. And you also shouldn't posit something for reason X and then posit something else that undercuts reason X, because that's inconsistent.
"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!! :-)
