Witten had a good argument in 1984 that a possibly consistent generalization of relativistic QFT was worth studying, but the problem is that decades and tens of thousands of papers later, as far as unification goes, this study has been a failure, taking the field down paths (extra dimensions, SUSY) which lead to complex theories that don’t look at all like the real world. I didn’t find it convincing then, since it seemed to me there was no reason to be so sure that a deeper understanding of relativistic QFT could not possibly lead to a consistent quantum theory with low energy limit GR. This is pretty much exactly the same argument he was making nearly forty years ago. My point of view is that string theory is the only significant idea that has emerged for any modification of the standard framework that makes any sense. The claims about consistency are either about models that don’t reproduce the real world, or about still-unrealized hopes and dreams (which Penrose characterizes as “Fantasy”) rather than anything well-defined.įor a very clear statement of his point of view from Witten, see the question and answer section of the recent colloquium talk, starting around 1:20, where he starts by emphasizing the rigidity of the framework of relativistic quantum field theory. Put simply, the problem is that there is no such thing as a well-defined string theory which successfully gives the SM and GR in four dimension. In my book and many other places, I’ve explained the many problems with this. The argument Maldacena and Witten are making is essentially the same one from the mid-eighties: string theory is the only possible consistent way to go beyond quantum field theory and get a consistent theory of quantum gravity. To get a clear look at his arguments, see a recent IAI interview In defence of string theory and his colleague Edward Witten’s recent colloquium talk What Every Physicist Should Know About String Theory. A very powerful and influential part of the physics community, which will be represented in the debate by Juan Maldacena, continues to insist on the centrality of this set of ideas. Maybe this debate will somehow lead to a substantive discussion of the main underlying problem, the nearly fifty-year dominance of a failed set (GUTs/SUSY/strings) of ideas about unification. Why promote such an atrociously bad book (see here and here) and broadcast Kaku’s absurd claims about this subject? Very odd is what leads into this debate, an interview with Michio Kaku about his new book. I noticed that the people at the Institute of Art and Ideas have put together a program for Monday that includes a debate on the topic of “Fantasy, Faith and Physics.” The framing of the debate contrasts the conventional view of science with an alternative possibility: “should we accept that some beliefs, especially in the foundations of physics, are akin to religious beliefs dressed in mathematical language to give our theories meaning?” This kind of misses the point about the current problems in fundamental physics, since I doubt any of the panelists are going to defend such an alternative. In this case, the only story that had such claims was one from Quanta Magazine, which explained that “the observations so far from NANOGrav and the other teams are consistent with what we’d expect to see from cosmic strings.” In the past, such observational results pretty reliably led to absurd claims about evidence for string theory that I could complain about, but that phenomenon seems to be dying down. Yesterday’s pulsar timing array and IceCube announcements unfortunately didn’t tell us anything about fundamental physics. No blogging here the past few weeks, partly because I was away on vacation for a little while, but more because there hasn’t been anything I’ve seen worth writing about.
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