According to a new article in New Scientist entitled The Theory of Everything: Are we nearly there yet? (unfortunately not available for free on-line), “The hunt for the theory of everything is turning into a road trip from hell – and don’t even ask who’s reading the map.” The article quotes Susskind and Weinberg as believing in the existence of a multiverse, even if this means that “all we can hope for from a final theory is a huge range of possibilities”.
Witten is referred to as a “string grandee”, and quoted as saying about string theory “More work has always given more possibilities – far more than anyone wanted… I hope that current discussion of the string landscape isn’t on the right track, but I have no convincing counter-arguments.” He’s welcome to my counter-arguments if he wants them: there’s not the slightest evidence for the landscape scenario pseudo-science, it’s incredibly ugly, not based on any kind of well-defined theory, explains nothing, and holds out no reasonable hope of ever explaining anything.
The article goes on to discuss the wishful thinking surrounding “M-theory”, quoting Witten as believing that M-theory may have a unique solution that fits our universe and explains the constants of the standard model. “Hope springs eternal” he says. Somebody seems to have given the writer the idea about M-theory that “theorists can prove that it exists as a mathematical construction, but they can’t actually write down its equations and there is no clear route towards doing so”, which is only true under a peculiar interpretation of the words “prove”, “exists”, and “it”. Lisa Randall is quoted as follows about M-theory: “We probably need fundamentally new principles… it’s not hopeless, but it’s going to require some deep new insight that we don’t really have.” She promotes her own work with Mukohyama on an alternate explanation of the cosmological constant.
The only person quoted in the article as thinking that there may be any problem at all with the way particle theory has been pursued for the last twenty years is Lee Smolin, who takes the absolute lack of any experimental evidence for string theory as a sign that the field may be off on the wrong track. He notes that “If you look back over the last 200 years, every decade or two there’s a dramatic advance, people always understand something new that couples theory and experiment… I suspect there is some right question that we’re not asking.”