First of all, this book neither touches upon the debates about falsifiability with regard to the Anthropic Principle in string theorists’ and especially Leonard Susskind’s “Cosmic Landscape” theory, nor Smolin’s alternative theory of Cosmological Natural Selection. It’s sole concern is today’s general state of physics as a science, and according to Lee Smolin, physics is in a sorry state indeed.
I admit I was shocked at his critical assessment of what has effectively been achieved, or rather not achieved, by String research. While String Theory has always and in principle been exceptionally promising, thirty years of research have actually delivered very little—far less than I’d somehow thought it had. While I was reading Leonard Susskind’s book The Cosmic Landscape, a strange feeling had crept up on me already that String Theory might have lost its grounding in reality in its attempt to cope with the cosmological constant and other recent findings. This seems indeed to be the case: according to Smolin, there is no ground to stand on. String Theory’s ever-promising developments seem to have caused a perpetuated self-delusion of the “it’s so good it just has to be true!” variety. Which makes me rather sad—I’ve always been thrilled by String Theory, and also by certain string-based developments such as Brane Theory, especially the Randall-Sundrum Model. All of which now seem to warrant a sober reassessment.
This should not be misconstrued. Smolin is not attacking String Theory because it’s String Theory, nor is he promoting (Loop) Quantum Gravity as his competing field of research: none of these and other theories have, according to Smolin, been borne out so far. His criticism against String Theory is more pronounced only because it has been the predominant academic paradigm for so long. And this is where Smolin’s criticism is aimed at: the way research has been conducted since the time of the relativity/quantum revolution. Thus, the fourth and last part of Trouble With Physics is about the philosophy of science, and Feyerabend, Kuhn, and Lakatos figure large. What Smolin proposes, in a nutshell, is that we need less peer review and more risk taking (courtesy of Feyerabend); less “normal” science and more “revolutionary” science (courtesy of Kuhn); and a return to the drawing board and the foundational problems of quantum physics. The latter not simply in order to “reconcile” quantum physics with relativity, but to develop a deeper understanding that might lead us to an underlying, “deeper” theory—a theory that is background-independent, makes sense of quantum physics beyond the Copenhagen interpretation, and unifies gravity with everything else.
This is the most sobering, most convincing, and most self-critical account from and about theoretical physics I’ve come across. (Not that there have been many such accounts, of course.) And, with regard to the history of String Theory and today’s Five Fundamental Problems of physics, one of the most readable and accessible texts to boot.