Not Even Wrong

I've been reading a lot of books about string theory lately, or more properly books about the failure of string theory to turn into anything like a real scientific theory that makes predictions that can be tested in the real world. String theorists often refer to it as the "theory of everything", since it (supposedly) unifies quantum field theory with gravitation, but its detractors sometimes call it the "theory of anything" because one can tweak the theory by altering the constants that define the Calabi-Yau manifolds and make the theory look like anything at all. Got an inconvenient experimental finding you can't explain in string theory? Heck, just perturb the six-dimentional manifolds for a while until the theory "explains" the experimental result.

It is said that there is no single string theory as such. Instead, there is a "landscape" of a huge number of string theories - according to one estimate, 10E1500 (that's 10 followed by 1500 zeros) distinct string theories. When pressed on the point, string theorists insist that the theory is right, even if experiments and common sense argue otherwise, and what is really faulty isn't string theory, but our understanding of what a fundamental theory should do.

I think all of this is nonsense. Granted, I'm no string theorist, but it seems to me that string theory fails several common-sense real world tests. The first is that it seems to make no verifiable predictions at all. This is like me theorizing that there is an invisible demon in my garage. It isn't provable either way, so it's can't be a theory in the scientific sense. Another is that the theory depends on supersymmetry to work, and I'm sorry, but I find the whole notion of supersymmetry kind of far-fetched. One would think, one would, that if supersymmetrical partner particles existed, at least some of them would be light enough to be seen in existing particle colliders. (Why, given that the electron has a mass of, what, a few hundred KEV, would its supersymmetrical partner is much, much more massive?) But no - they're all just a little too massive to be produced by existing hardware, and when CERN's Large Hadron Collider comes on line, I suspect they'll still be a little too massive to be seen. Is it reasonable to assume that all the supersymmetry partners are above the 14 TEV or so energy LHC can generate, or is it reasonable to assume that in fact supersymmetry is an elegant mathematic formalism that has no connection with the real world? Another thing that bothers me is that string theory currently exists in five forms, and some of them predict the existence of tachyons, which seems to me to be prima facie evidence that that particular theory has a problem. (But I'm also dubious of the Higgs particle, which is predicted by quantum field theory and yet remains slightly too massive to be revealed by existing particle accelerators. So in a sense, nothing pleases me, since if I wave a magic wand and make the Higgs particle go away, nothing forces symmetry breakage in the Standard Model and the universe would have to look very different than it really does. But I'm not as dubious of the Higgs particle as I am of supersymmetrical partners - one particle being too massive to appear I can roll with ; a whole menagerie of them being too massive to appear starts to tickle my erroneous zone.)

String theory (more properly supersymmetrical string theory) could still turn out to be right. But it strikes me that the super-smart people behind string theory want me to take an awful lot on faith, including a series of conjectures that haven't been proved, as well as the entire notion of supersymmetry and the existence of Calabi-Yau manifolds that curl up the 'excess dimensions' that the theory requires to work. All of this could be true, but from where I sit, firmly in the world of engineering where theories and mathematics have strong predictive power, string theory seems a little suspect.

It's also possible I have a personal bias. I once knew a fellow who liked to joust with me on intellectual matters. I am an engineer by trade and tend to believe fundamental laws and mathematics, especially ones like Newton's Second Law of Motion. He was much more accomodating in his view of the universe and believed, among other things, that entropy can be reversed, that perpetual motion machines can be built, and that Nazi scientists had built a working anti-gravity drive. So when he told me he understood string theory, I automatically lumped string theory in with all the other junk he believed, junk that I will, for the sake of courtesy, merely call highly dubious.

I don't know what the real "theory of everything" is. I am forced to agree with Leonard Susskind to the extent that if there is a "theory of everything" we simply may not be smart enough to understand it, let alone formulate its basic mathematics. But I am also loath to abandon Einstein, who believed that we would know we had stumbled on the "theory of everything" because it would be beautiful and simple. String theory is neither beautiful nor simple, and so I remain dubious.