[QUOTE=Dominic Mulligan]
But doesn’t this seem a bit ridiculous? Why should there be so many hidden dimensions, and why is seemingly nigh on everyone in the theoretical physics community in love with string theory? Shouldn’t a theory that proposes so many extra dimensions be treated with a lot of suspicion (Ockham, and all that)?
Is there much opposition from within the theoretical physics community to string theory? Just what is it about ST that makes it so appealling and what is the evidence?
[/QUOTE]
First of all, if you want to talk of “string theory” in general, you should speak of it as “M-theory” or the specific individual theories which comprise the former. Second, why so many dimensions, and why should they be “compactified”, or “out of phase”, or othewise hidden except for the standard three spatial dimenions and the one (rather peculiar) unidirectional time dimension? The reason is the math, or more specifically, being able to fill in all of the empty spaces in the matrices of the governing equations in a way that is symmetric and elegant. Ultimately, we’d like to believe that the underlying rules of the universe extend from a uniform, consistent set of basic principles, even if the expression of these is complicated, similarly to how mechanics and electrodynamics all thrash out in a very elegant way. This is very appealing and explains the adoration of M-theory, but it is admittedly a fad that has provided little in the way of testable, falsifiable hypotheses, and indeed one can essentially tune the model via selection of hidden constants to obtain essentially any result desired in the same way that Warner Brother’s animators create their own physics involving desert fowl and the predators that stalk them.
Regarding Lord of Ockham’s shaving apparatus and reasoning therefrom, the principle there stated is that given multiple explanations for an event, the one that requires the least gyrations or leaps of logic (which is not necessarily the simplest or having the least steps) is generallhy preferred. For instance, having the world created by being spat out of the mouth of a big tobacco-chewing pandimensional redneck with a propensity toward atavistic violence and a misogyny problem is a pretty simple explanation, but also one that lacks much in the way of physical evidence and requires a lot of “faith” in that the Chosen High Priest who makes a very good living off of the 10% tithes from his flock of followers isn’t just grifting on, while more complex explanations involving nucleosynthesis of heavy elements from Population II stars, tectonic plate theory, natural selection, et cetera is a heck of a lot more compex and requires several years study of various fields of basic and more advanced sciences to truly appreciate, but ultimately gives a more pragmatically satisfying answer. Ockham’s Big Sharp Blade is a principle of discriminating between equally founded alteratives but does not offer ultimate guidance.
That being said, many people are suspicious that M-theory is not really getting us any closer to actually knowing what it’s all about, and all but its most devout advocates don’t pretend that they’ve fully grasped the nettle and are ready to give us the Ultimate Answer to Life, the Universe, and Everything. But it is, from my somewhat superficial attempts to get into it in basic mathematical depth, joyously elegant until you get to the boundary to something not well explained, and then it gets mucked up like a traffic jam on the New Jersey Turnpike.
It’s still not as bad over arguments about interpretations of quantum mechanics, though.
Stranger