## Friday, April 06, 2007 ... //

### Max Tegmark: The Mathematical Universe

Those of us who know Max Tegmark as a mainstream perfectionist researcher who deals with real cold cosmological data will be amused by his work

in which he tries to decide the validity of the External Reality Hypothesis, the Mathematical Universe Hypothesis, the Computable Universe Hypothesis, and whether or not we live in the Matrix. ;-)

Hep-th

On hep-th, Kallosh and Linde are testing string theory with the CMB. Green, Ooguri, and Schwarz argue that one can't decouple supergravity from string theory in dimensions higher than three and N=8 supergravity probably belongs to the swampland - very much the same arguments we explained at the end of Finiteness of SUGRA.

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Very interesting stuff.

Is this guy a former student of Seth Lloyd, the guy with "Computational Universe"?

In my opinion, we might be living in a matrix, but we will NEVER be able to determine whether our reality world is a matrix or not. The important thing to note is that our universe is finite, with a finite amount of entropy. That means it can be fully described by a finite number of digits. Those digits could be written onto a book, saved into a computer chip, or stored in a giant quantum computer. You never know.

For example, the whole universe we saw, might just be a giant TV screen some intelligent ET life set up, enclosing our whole solar system, projecting various photons our way emulating what a universe should look like according to certain theoretical model. Making every thing look so real. Such a giant TV screen would be incredibly complicated. But the complexity would be finite, not infinite. And any thing with finite complexity is conceiveable by a super intelligent being. We would not be able to tell whether such a giant TV screen exists or not until we send a spaceship actually check it out.

Of course that's quite a stretch of imagination. But mathematically you can not say it is impossible.

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I tried to leave this link to a conversation about the MUT I tried to strike up at Google groups on sci.logic.

The link was way too long, let me try this:

A MUT discussion.