I, too, used to believe that consistency is the most important, at least w.r.t. empirical truths. However, forcing every theory and thought to be perfectly consistent is so crippling, that the progress of useful empirical truths is overly hindered.

It reminds me of the travelling salesman problem, which, although N-P complete, can usefully be solved by Monte Carlo in polynomial time. It is only for a tiny fraction of the problem space that you really have to compute for exponential time. It’s somewhat analogous to using ’sloppy’ math, perhaps?

Two confused philosophy students get married and try to decipher the meaning of life from the voice of nature at its loudest during their honeymoon at Niagra Falls.

Far upstream, a little transistor radio has fallen into the river, and the newlyweds hear it playing the incomprehensible hit “Louie Louie” as it goes over the falls.

Life obviously has no meaning, and the newlyweds throw themselves off the catwalk onto the rocks below.

Moral: Nature speaks a zillion languages, and whatever we hear of them is the outcome of a long series of biological accidents, like a typical honeymoon at Niagra Falls.

More interesting is Max Tegmark’s contention that the Physicists’ holy grail of a Theory of Everything forces us to believe that we live inside a mathematical structure, and that it is part of a mathematical multiverse of mathematical structures.

Shut up and calculate,
1 Oct 2007.
Comments: This is the “director’s cut” version of the September 15 2007 New Scientist cover story. For references, see the “full strength” version at arXiv:0704.0646
Subjects: Popular Physics (physics.pop-ph); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Theory (hep-th); Mathematical Physics (math-ph)

I advocate an extreme “shut-up-and-calculate” approach to physics, where our external physical reality is assumed to be purely mathematical. This brief essay motivates this “it’s all just equations” assumption and discusses its implications.

QFT isn’t inconsistent, just it is not known yet if it is consistent

When physicists reason they often do so using techniques that aren’t generally valid. They may work in one particular situation but not in another, without a good explanation as to why. For example, in the absence of proper foundations to QFT, physicists use heuristic arguments about limits and infinities that really are not valid mathematics. I guess you could view this not as an inconsistent theory, but as a theory with a very complicated set of deduction rules about when you can use this and that rule. So complicated, in fact, that the rules haven’t been codified and you have to learn them by reading between the lines of your lecture notes.

This is quite different from mathematics where the moment you smell a whiff of inconsistency somewhere it’s imperative that you rush towards it as fast as you can.

Not always, and not everybody. I for example have no problems with (some level of) sloppyness and heuristic arguments, as long as at least the objects in question are more-or-less clearly defined. The problem is, when you talk with physicists, or read physics books, they are often not…

(btw, I don’t think “inconsistent” is the good word here. QFT isn’t inconsistent, just it is not known yet if it is consistent)

“Don’t knock masturbation. It’s sex with somebody I love.”