String Theory

I don’t know much about string theory except (1) it attempts to unify two of most successful theories of physics, viz. quantum mechanics and Einstein’s general theory of relativity; (2) it countenances 10 (or is it 11?) dimensions, coiled up in a very tiny portion of spacetime; and (3) asserts that “strings” are the fundamental constituents of all matter, and give rise to the four fundamental forces of nature by unique “vibrations” of those “strings”.

I also know, though, that many physicists have come out and said that String Theory is untestable. But how are we to understand this charge? Some say if it’s not testable it is as good as theological hypotheses, e.g. God exists. I am not so pessimistic. My guess is that String Theory is testable, IN PRINCIPLE, but not IN PRACTICE. That is to say, we can imagine an experiment that, if it gives us the right outcomes, string theory will be either directly or indirectly confirmed. Consider the Ekpyrotic Model in cosmology. There are imaginable experiments that would test this model against the Inflationary Model (aka the Big Bang Theory); the trick is putting it into practice, actually conducting these experiments. The author’s of this model are holding their breaths for future testing, which, if they receive their funds and experimental apparatus, the Big Bang Theory will go against a new kid on the block. The Ekpyrotic Model, interestingly enough, incorporates string theory; that is, string theory is indispensable from use of the Model. Thus, if the Model is confirmed, string theory receives indirect confirmation.

So, maybe I’m missing something. Is String Theory truly untestable in principle, such as God’s existence is argued to be?

I think that the current position of string theory is that it has made no predictions and if it were to make a prediction then the energy levels needed to observe string theory would not be tesable in current experiments.

In principle string theory could make a testable prediction. On the otherhand as it stands string theory hasn’t made any predictions so its not falsifiable atleast in its current form. String theory probably needs to be better understood before a version of string theory can be said to be falsifiable.

Personally i think string theory maybe more of a new language to describe nature rather than providing us with physical principles as such. In that case it maybe that string theory is prehaps the best suited language in which the principles of both quantum mechanics and general relativity can be expressed. This may just be my way of justifying my own work, combining QM and GR without string theory.

The String Theory is an attempt, knowlingly or not, to get away from the Big Bang.

The notion of “strings” at the Planck scale (or wherever) whose configurations correspond to particles is reasonable IMO, but what I don’t sympathise with is 30 years of mathematical castle-in-the-sky building, all done in the absence of evidence. Hundreds of people have got a stake in this monster now, and if/when the crazy results they’ve produced are disproved, there’s gonna be a storm.

Big names will scramble to save face, but I won’t be ruffled, because I never bought into the idea.