The acceptance of string theory into the mainstream lexicon is curious. Its advanced mathematics precludes all but the most highly trained and talented scientists and mathematicians from understanding it. It's science that requires faith in those who tell us how the universe works. In The Trouble With Physics, Lee Smolin argues that this faith may have been misplaced.
The book opens with its most engaging sequence, 50-odd pages in which the great discoveries in the history of physics are cast as a sequence of unifications. Toward the end of this section, Smolin describes an experiment that settled the dispute between Einstein's theory of general relativity and a competing theory that unified electromagnetism with gravity by positing an extra dimension. The experiment confirmed Einstein's predictions, sending the extra-dimension theory to the dustbin. Because string theory requires an as-yet-undetermined number of extra dimensions, Smolin subtly manages to denigrate it by aligning it with an unsuccessful predecessor. In doing so, Smolin also indirectly aligns himself with the physicist whose name has become synonymous with genius.
Columbia mathematician Peter Woit argues that calling string theory a theory is exceedingly generous. The title of his new book, Not Even Wrong, was a phrase reserved by renowned physicist Wolfgang Pauli for ideas that were so incomplete that they could only aspire to someday being wrong. Indeed, being wrong is a problem for string theory the few hypotheses it has suggested are untestable, and there are so many variations of string theory that it's possible to find a version to fit virtually any experimental observations. Consequently, it fails to meet Karl Popper's criteria of falsifiability for science, leaving string theory in the murky, decidedly unscientific realm of metaphysics.
Both Smolin and Woit conclude by criticizing the hegemony of string theory in the top physics departments in the country, calling for more room in those departments for non-string theories. Of the two books, Smolin's is the more accessible to the lay reader as well as the more even-keeled. Woit's tome is in places more technical and occasionally more vitriolic, much like his frequently visited and often contentious blog of the same name. Importantly, though, both books remind readers that popularity and pervasiveness are not the criteria upon which scientific disputes should be settled.