chickenfeet

These days it's pretty hard to find the line between theoretical physics and applied mathematics. Time was when one could relatively easily apply physical tests to theories to see whether they were promising or not. That's really no longer the case. Most of the current cutting edge theories deal with energy levels that are never going to be experimentally achievable so the only bases for deciding whether a theory has merit or not are either popularity (which is fraught of course as Kuhn and others have pointed out) or some, essentially, aesthetic judgement. Of course this doesn't bother 99% of the rampaging herd of string theorists, whether they consider themselves mathematicians or physicists, because the prevailing zeitgeist basically eschews any serious discussion of truth in the ontological sense.