Shtetl-Optimized, as I’ve mentioned elsewhere, is the blog of Scott Aaronson. And, as I’ve just linked to his wiki page, I don’t feel especially inclined to say much about his biography. Aaronson’s field of research is quantum computation; an exciting new field with possibilities. It lies at the intersection of mathematics, physics, computer science, and electrical engineering.

I have found Shtetl-Optimized to be well-written and informative. His latest post, dated March 22nd, is about Tegmark, his book *Our Mathematical Universe*, and Tegmark’s idea of the Mathematical Universe Hypothesis. Aaronson’s writing is lively and witty, you’ll find. He writes about both the human-ness of Tegmark’s writing, as well as his disagreement with Tegmark’s fundamental thesis, which is that the universe is not just mathematical, but *is itself* the mathematics. One of Aaronson’s reasons for finding the Mathematical Universe Hypothesis (MUH) unconvincing is that it is not impressive science – defined as when elegant mathematics lines up with facts as we have experienced them. I think this is exactly right. It does seem unlikely, as well, that anyone could ever devise experiments to test the MUH. This is my issue with all multiverse theories: while theories are definitely a part of science, and important (theories are the goal, after all!), experiment is the life-blood. A theory without experiment exists only in men’s minds, and has dubious predictive power.

Shtetl-Optimized is probably not for the layman, however, as he has no hesitation in getting “technical”. If you are interested in popular science, this blog would stretch you. Perhaps that is what you’re seeking, and if so, you’ve found a good place. It’s like classical music: you get out of this blog what you put into it.

I left a comment there which (if it passes moderation) can be seen here:

http://www.scottaaronson.com/blog/?p=1753#comment-103427

Max Tegmark is an interesting fellow. I think he is the first to admit his MUH is more “idea” than “fact”, and from the standpoint of “hard science” perhaps belongs more properly to “metaphysics” (an extremely rare use of BOTH meanings of that word here!).

Just so, there is a discipline known as “mathematical philosophy” which one does not need to be conversant in to be a working mathematician. While such a field may not have much to say in terms of “actual math”, it is sometimes good to ask ourselves: “what is it we are doing, and why are we doing it this way?”. Our activities do not occur in an intellectual vacuum, our beliefs and feelings inform the choices we make.

For example, some mathematicians exhibit a strong tendency towards “minimalism”, and write in as terse a style as possible. Thus the ease with which they communicate is drastically affected by an aesthetic consideration, or working within a system with minimal assumptions. Is logic developed through use of alternative denial “better” or “worse” than the classical connectives? I suppose it depends on your point of view, and this is a subjective, not objective, matter.

Of course, many “meta-mathematical” and/or philosophical topics deals with foundational issues. “Up here” computing Fourier coefficients, for example, the “truth” of the continuum hypothesis isn’t particularly relevant. On the other hand, one ought to be leery of “taking things on faith” in a logic-based discipline such as mathematics (such a position is absolute anathema in science, where empirical substantiation is the sine qua non), so the things we take as given ought to be examined, from time to time.