Mark Gonyea (a.k.a. MrOblivious), “String theory”
From about the tenth paragraph of this article on, physicist Sabine Hossenfelder bashes string theory mercilessly in her blog BackReaction. In fact, she employs a very interesting strategy: she effectively depicts string theory as what Imre Lakatos would call a degenerating research program — lacking in heuristic power, with mounting ad hoc elements, and generally staying most of the time behind experiment, trying to catch up with it, instead of anticipating it:
“So, you asked, why not string theory? Because it’s an approach that has been fixed over and over again to make it compatible with conflicting observations. Every time that’s been done, string theorists became more convinced of their ideas. And every time they did this, I became more convinced they are merely building a mathematical toy universe.”
I am not sure whether I concur with all the points Sabine makes against string theory throughout the text, and I guess I’m still not prepared to leave string theory outside the conceptual landscape of contemporary physics altogether; but I must admit paragraphs 10-15 of the text constitute one of the most intelligent criticisms I’ve seen of it recently.
There are some slips, however, and ones that simply wouldn’t go unnoticed by philosophers of science. One of the most conspicuous ones is when Sabine at a certain point writes:
“I don’t see what one learns from discussing which theory is “better” based on philosophical or aesthetic criteria. That’s why I decided to stay out of this and instead work on quantum gravity phenomenology. For what testability is concerned all existing approaches to quantum gravity do equally badly, and so I’m equally unconvinced by all of them.”
In fact, many of the criticisms she presents in her discussion are themselves motivated by cognitive values, and expressed by (so-called) “philosophical” or “aesthetic” criteria. (What about calling some of them “conceptual” values instead?) Even the “degenerating phase” depiction of the string program pressuposes a certain conception of rationality and certain standards that are of a philosophical nature. Even the notions of “testability” and “evidence” she’s been employing here (together with a lot of physicists) are far from being naively empiricist ones, of course — and these in turn involve taking some philosophical sides. Testability here requires scientific community to undertake quite a heavy process of construction of objectivity; on the other hand, there is a lot of experimental methodology crucially at play here that depends on quite non-trivial interpretive choices and requires critical assessment of the results.
(There are a few more technical, properly conceptual aspects as well that should be mentioned with respect to string theory: for example, string theory doesn’t need to undergo renormalization, and that should be considered as a genuine advantage.)
There are values everywhere in science, both cognitive and social, and there is no way of blocking them outside the legitimate domain of the scientific debate. In fact, most of the orthodox views and discourses about science as “objective, universal, neutral and value-free” are themselves affected by values, albeit implicitly.