“So what would you do if string theory is wrong?” asks string theorist Moataz Emam of Clark University, US, in a paper posted on arXiv yesterday. It’s obvious, you might think. String theorists would briefly mourn the 40 years of misspent speculation and leave furtively through the back door, while anti-string theorists would celebrate in light of their vindication.

Not so, says Emam — string theory will continue to prosper, and might even become its own discipline independent of physics and mathematics.

Oddly, the reason Emam gives for this prediction is precisely the same reason why many physicists despise string theory. For example, in reducing the 10 dimensions of string theory to our familiar four, string theorists have to fashion a “landscape” of at least 10^{500} solutions. Emam says that such a huge number of solutions — of which only one exists for our universe — may make string theory unattractive, but in studying them physicists are gaining “deep insights into how a physical theory generally works”:

So even if someone shows that the universe cannot be based on string theory, I suspect that people will continue to work on it…The theory would be studied by physicists and mathematicians who might no longer consider themselves either. They will continue to derive beautiful mathematical formulas and feed them to the mathematicians next door. They also might, every once in a while, point out interesting and important properties concerning the nature of a physical theory which might guide the physicists exploring the actual theory of everything over in the next building.

Peter Woit, author of the string-theory polemic Not Even Wrong, notes on his blog that physicists looking to pursue string theory for its beauty should “go and work in a maths department”:

The argument Emam is making reflects in somewhat extreme form a prevalent opinion among string theorists, that the failure of hopes for the theory, even if real, is not something that requires them to change what they are doing. This attitude is all too likely to lead to disaster.

I believe when a physiscist starts to build a mathematical theory his first prerequisite is to use mathematics that is capable of capturing the physical reality. Now if you are searching for a theory of everything then the mathematical model must in theory be capable of explaining the behavior of all of the four fundamental forces, in all time frames. I think this challenge has led to string theories and M theory. I am pretty sure it was not the other way around. The question now is if string theory leads to n**500 possibilities and untestability at this present time should this research be discredited? Well, if the theory can be shown never to be testable then there is a strong case against it. I am not sure that this has been shown to be the case yet. I believe the energies required are very high for testing it and may be well beyond reach for the forseable future. As far as the possibilies are concerned (n**500), I think this is less of a objection. Would you not think that the way a master chess player (like Kasparov) is able to disregard the spurious solutions and find the optimum one is the way a great theorist could one day find the final solution (so long as the theory is qualitatively the right one)?