Warning: if you follow this blog, you’ve heard this many times before, so can move on to something more interesting now.
There’s a video conversation between Brian Greene and Lenny Susskind from last week here. At 44:02, Susskind has this to say:
One of the chief critics is a colleague of yours, I believe. And he is rather forcefully maintaining that string theory, until it can produce a success of the kind where you actually can produce a number and that number can be checked with experiment, that it doesn’t have any value.
The main reason for this post is just to reiterate that this is not what I think. The problem with string theory as a unified theory is not that it hasn’t made a tested prediction, but that it has made no predictions, of any kind. It’s very clear now that, as a theory of the real world it’s a speculative idea that just doesn’t work. As to whether it has “any value”, you have to first define what “string theory” is. Under some definitions there are things of value, under others not.
Susskind goes on to accurately explain that any well-defined version of string theory (which he calls “String theory”, capital S) definitely doesn’t correspond to the real world. But, he argues, maybe some new, unknown variant of String theory will work. According to him “It’s the only game in town” and “you have to see it through”.
Brian later asks him “Is there anything that you could imagine happening in the field that would convince you that this is time to put it away?” “Finding it mathematically inconsistent” comes up, but he has already said that this is about an unknown new idea that would make things work. “I don’t know the answer to that” is then his answer: nothing would convince him. About other approaches doing better: “I think both you and I probably don’t put a lot of stock in there.”
In case you haven’t seen this, something from a Kurt Vonnegut magazine piece:
A guy with the gambling sickness loses his shirt every night in a poker game. Somebody tells him that the game is crooked, rigged to send him to the poorhouse. And he says, haggardly, “I know, I know. But it’s the only game in town.”
