Good retort to the suppostion that physics is becoming more like a religion,
Exile :tup:. I think I may print out post#5 for re-reading as the theory thumbnails are pretty good.
It does seem to me, as an interested layman, that mathematical elegance is starting to overtake predictive content as a primary yardstick for the worth of a new theory. My query lies in the old saw that if a theory admits to no way for it to be tested and disproven then, as far as my primitive (Popperian
) scientific knowledge goes, that's not science.
That's the primary point of both books. And what's interesting is that the point is not disputed even by ardent string theorists; their response instead is to make snide comments about the relevance of the Popperian yardstick (in his book, Woit cites a contemptuous remark posted on some string-theory website or other about the 'knee-jerk Popperazi', a clever way of expressing what
I think of is the abandonment of the basic scientific touchstone: knowing in explicit detail what your hypothesis commits you to and being prepared to abandon that hypothesis if you keep coming up empty). He points out that the string theorists have yet to specify just what their answer to the question
If this were wrong, how would we know? would be—what would have to happen in order for them to be willing to give it up.
Perhaps it is simply the fact that my knowledge of the background mathematics isn't deep enough?
No. That's not it. The mathematics involved are novel and frighteningly difficult (way more difficult, if I understand what I've read, than the differential tensor geometry that Einstein appropriated from a couple of late-19th century Italian mathematicians as the geometric language which he needed for general relativity, though at the time
that was regarded as being at the limits of comprehensibilty, at least so far as working physicists were concerned... how things change, eh?)
Arni can tell you a lot more about it, I'll bet, if you've got the nerve. But that's not the problem. The problem is attitude: what you are willing to give up in order to get what you want. We have exactly the same problem in syntactic theory, so I feel Woit's and Smolin's pain, and that of the other dissenters (of whom there seem to be quite a few). The problem seems to be that a lot of physicists see no other way to link quantum field theory to gravitation, and the
hope that string theory holds out of a successful unification—and that's all it is at the moment, a hope—has created in the mnds of many of the string theorists the following (and IMO deadly) premise:
String theory is too good to be false.
As Smolin points out, beautiful premises in the hard sciences often fail the test of confrontation with the data, and are discarded in normal scientific practice. What's happening in string theory is a frightening anomaly in science precisely because, when the strongest version of the theory is confronted with the facts and fails, string theorists do not go back to the drawing board. What they do is reject the relevance of the facts, in effect, in a way which changes the nature of the enterprise completely. Too many vacuum states? No way to reconcile the theory with the apparent value of the cosmological constant? No motivation for
why the eleven dimensions of space you need are compactified in such a way that only four of them—the classic four of spacetime—are measurable? Simple. 'Generate'
all the possibilities that the theory still allows—the infamous one followed by hundred zero, raised to the fifth power—and then haul in the anthropic principle so that you can say, 'well, they're all there, and we observe the values for the fundamental constants of nature that we do because those values belong the set of sets of possible values that correspond to the possibility of intelligent life. Now go away and don't bother me.' And if you say, well, isn't that a bit expensive, just to get the hope of unifying gravity with the other forces of nature, the answer will be, well no, because that's the only game in town that offers that hope.
That, however, seems to be sheer propaganda—there are other approaches out there, but they aren't being developed very fast because if you want to get a job in physics, you better not be working on loop quantum gravity or one of the other alternatives. The people hiring are all string theorists, and they don't want to hear what you have to say...
I don't really understand how something being a theoretical mathematical construct based upon certain un-testable assumptions is different in character from a group of theologians debating how many angels can dance on the head of a pin. If some of the foundations are taken as read (on 'faith' if I may call it that) then the whole model inherits that 'flaw' of lack-of-disproveability.
If those assumptions (or the model that derives from them) are testable for predictive capability then the 'faith' element goes away, otherwise the fascinating theories of the nature of the universe are mathematical poetry.
Well, speaking of poetry, remember Keat's profoundly misleading conclusion to 'Ode on a Grecian Urn':
Beauty is truth, and truth beauty,
That is all ye know, and all ye need to know.
As a guide to hypothesis formation, yes. But as the
test of the hypotheses formed, no—and the history of science is full of warning about how big a false step adopting that position is. This is the problem:
Homo sapiens, Linnaean taxonomic name notwithstanding, tends to be not very wise, even when it's being very smart...
I'm not being deliberately obtuse here by the way,
? You're not being obtuse at
all, Mark, these guys in the trade are saying exactly the same thing!
I really am that stupid {
} in that picking and chosing what assumptions you like to make the maths work out sounds dangerous close to the kind of pseudo-science jiggery-pokery we get up to in economics :lol: .
Or in my own field, or in many others as well. And it's particularly bad if it happens in physics, the hardest of the hard physical sciences, because economists and syntactitions and all the rest can say, well, if
those guys do it, why are you knocking
us for doing it?? When your gold standard starts showing signs of being iron pyrite, you're in a hell of a lot of trouble....
I think a warning should be placed on this thread:
"WARNING: DO NOT OPEN UNLESS YOU HAVE HAD SUFFICIENT AMOUNTS OF COFFEE OTHERWISE YOUR BRAIN MIGHT GO INTO SEIZURES"
All joking aside. Interesting discussion fellows. Sorry I have nothing to add. I will read it more in depth after my second or third cup.
The technical details are important, but the really important thing is that the points that Woit and Smolin make are not really disputed by string theorists; they just don't see it as relevant. Consider the following negative comment about string theory:
You don't know what you are talking about.... The state of physics today is like it was when we were mystified by radioactivity... They were missing something absolutely fundamental. You are missing perhaps something as profound as they were back then.
.
Pretty damning, eh? Now change the 'you' here to 'we' in all cases, and you have the actual comments of David Gross, one of the most active and intense
advocates of string theory, a Nobel Prize winner for work on quantum field theory, delivered at a meeting of a conference to 'celebrate the theory's progress', as Smolin (p. xv.) reports dryly. Gross is talking about his own work and his colleague's work... and this is not unusual to hear from string theorists! But they won't give it up, or even step back from it a bit and try to rethink the whole project. It's, well, too good to be false.... :uhohh:
); and at the same time, if you're a graduate student in syntax, there are maybe five major research departments in the US where you can reasonably contemplate a job opening up that you'd be eligible for—us, Stanford, UT at Austin, Chicago, maybe Michigan (if they ever decided to hire a theoretical syntactician, and it's not really a major department, come to think of it) and one or two others. All the rest of the departments in the US are secondary or tertiary branch plants of MIT, or are trying to be...
