[LINK] Forty Years of String Theory: Reflecting on the Foundations

Those of us interested in “fundamental physics” may find a few interesting tidbits in the latest issue of Springer’s Foundations of Physics. It has contributions from the prominent figures in String Theory and related fields, such as the Nobel laureate Gerard ’t Hooft, father of the anthropic landscape Leonard Susskind and one of the founders of the leading alternative to the String Theory, Loop Quantum Gravity, as well as the author of several popular books about fundamental physics Lee Smolin. Eric Verlinde, the author of the controversial Entropic gravity model, also contributed. A couple of philosophers of science added their two cents.

While Springer is not an open-access publisher, this volume is free, as are many others during December 2012.

A few quotes from the introduction, which seem relevant to the issues of truth, realism and rationality:

“He [’t Hooft] compares string theory to other theories and models which are not free of problems but we generally consider to be well-defined: celestial classical mechanics, quantum mechanics, and QCD, and concludes that string theory is not in as good shape as any of these theories.”

“Rickles develops a version of the “no-miracles argument” for scientific realism to the case of mathematically fruitful theories, thereby defending the rationality of those who pursue string theory in the absence of better alternatives, rather than making a statement about the truth of the theory.”

“Susskind argues that developments in string theory are telling us that a narrow form of reductionism is wrong: “[I]f one listens carefully, string theory is telling us that in a deep way reductionism is wrong, at least beyond some point.” The reason is that various string dualities interchange what is fundamental and what is composite, large and small lengths scales, high-dimensional objects with lower-dimensional objects, and so on. According to Susskind, “In string theory this kind of ambiguity is the rule.” “Personally, I would bet that this kind of anti-reductionist behavior is true in any consistent synthesis of quantum mechanics and gravity.””

If you were to read only one paper, make it the one by Michael Duff. Here is the abstract:

Using as a springboard a three-way debate between theoretical physicist Lee Smolin, philosopher of science Nancy Cartwright and myself, I address in layman’s terms the issues of why we need a unified theory of the fundamental interactions and why, in my opinion, string and M-theory currently offer the best hope. The focus will be on responding more generally to the various criticisms. I also describe the diverse application of string/​M-theory techniques to other branches of physics and mathematics which render the whole enterprise worthwhile whether or not “a theory of everything” is forthcoming.”