I find it very amusing in the last word. Thanks for the humor, but string theoreticians are over-qualified languists in inventing new words:-)

ST doesn’t just describe “almost” any thing. It describes much much more than everything in the world adds up. That’s exactly the problem. When the complexity of a theory allows it to describe more than what this universe can hold, that’s no longer a physics theory since physics strictly limit itself to the observables within this universe only.

I keep seeing STers sing the praise how ST is rich of mathematics structures and how much beauty you can find within the theory, and they can’t believe that a mathematical frame work so rich in content could have nothing to do with the real world at the end.

What they don’t realize is it is exact the problem when you have a theory too rich and provides too much structure than what is needed to encompass the whole observable universe!!! It makes the whole thing “vacuous” when you realize just what an insignificantly small portion of that theory actually describes the universe

One could propose a theory living in 137 dimentions, it surely will provide even richer structures than the current 11-D string theory. It would also be more “vacuous”.

I think even a flat 4-D theory is alittle too bigger than what the universe can hold, as we already see. A theory of flat, infinitely extending 4 dimentional spacetime of precise coordinates provides more structures and information than what the actual universe holds. The result is we see a universe that is limited in size and has fuzzy coordinates. The richness of the universe is bounded by boundary, so it is described by the conditions of the 3-D boundary of the 4-D spacetime. That’s the holographic view.

Quantoken

-drl

Please don’t repeat the argument. I took a look again at your comment I deleted, and it still seems to me that it is about a calculation that interests you but doesn’t have anything to do with the topic of this posting (predictivity and anthropic reasoning in string theory).

I don’t think you can convincingly argue that the current superstring theory framework can’t support YM fields. The problem with the quantized superstring is not that it can’t describe interesting physical degrees of freedom, but that it can describe almost anything. It’s too ill-defined for anyone to be able to show it is inconsistent, but it is increasingly clear that it is vacuous.

I will repeat the argument if you wish.

-drl

(Sorry if I resort to bad humor sometimes. Nip nip nip.)

I think this “landscape” business is just playing with words. Finally string theory has a lot of ground states and one doesnt know which one to pick. The best thing is that _none_ of these vacua come close to describing the real world.

That’s not surprising. No one could say anthropism is wrong, since it is derived from pure logic. How could we possible living on a planet hostile to life, and the planet sits in a universe impossible to create stars and planets? So it is without question that anthropic principles are CORRECT.

The only thing that can be questioned against anthropic principles, is not whether it is correct or not, but whether it is science or not.

There are things that are absolutely correct, but is not science. Science does not necessarily have to be correct, since a theory we think is correct now may be replaced by a more accurate better theory in the future. Science have to be able to make predictions of the nature to be useful, science have to provide a mean for someone to potentially disproof itself through experiments or observations. Only when a theory makes prediction that can be verified or contradicted, and when it came out such predictions are verified instead of contradicted, will that theory be considered science.

What’s being disputed, is whether anthropic principles, although correct, does it have that predictive power at all? Some think it has, some do not. I personally think it does have predictive power, but very limited and definitely does not explain things unrelated to the condition of our existence. For example it does not explain why there’s homosexuality, which is strange from the biological point of view. I would say anthropic principle is probably some sort of semi-science.

Even the widely accepted standard of what is considered science may be subject to question itself, due to the Godel theorem. For example mathmatics, 1+2=3, that’s absolutely true, it does not even provide a potential opportunity for any one to possibly contradict itself, using experiment or whatever, so, then, is it science or not if it can never be dis-proven?

Quantoken

Hardly. I just don’t think that they care. As I said, plenty of people are perfectly content to continue working on whatever they’re working on and let the anthropic people do what they want.