Thursday, September 14, 2006

String Nonsense

As I've always been skeptical of string theory for both scientific and theological reasons, I was delighted to hear of Lee Smolin's book, The Problem with Physics, which exposes string theory as pseudo-scientific nonsense (the book is well-summarized in this article on For those of you who are not aware, string theory proposes to explain the origin of the universe by positing the existence of extra dimensions (some versions use as many as 25 dimensions). It's an interesting thought experiment, but there's no evidence that such extra dimensions exist. Moreover, string theory is not experimentally testable - the sine qua non of a scientific theory. Smolin therefore argues that string theory is not science, and that it more closely resembles philosophical speculation or outright science fiction. Sadly, none of these arguments have stopped string theory from gaining widespread acceptance among the faculty in physics departments around the world.

So what's go on here? My suspicion is that physics (more specifically, cosmology) has reached something of a dead-end with regards to the existence of the universe, such that any "explanation" it can offer will likely be as speculative as those provided by philosophy or religion. Indeed, there are solid philosophical reasons for thinking that science itself could never account for the existence of our particular universe, but this won't stop scientists from trying, of course.

I've long wished that scientists would learn to work within the epistemological boundaries of their discipline, and refrain from offering up such "scientific theologies" as string theory. But having spent a fair amount of time in the scientific community, I'm quite sure that we'll be treated to more of the same in the future. This is because scientists love to engage in metaphysical speculation, although they usually make the fatal mistake of confusing such thinking with actual science (for examples of this phenomenon, please consult the writings of Carl Sagan, Francis Crick, Daniel Dennett, Sam Harris, and all the others who claim scientific proof for the non-existence of God). In their urge to destroy religion with the sword of science, these fools have ironically transformed science into a religion of its own.


CPA said...

Lubos Motl has a wierd review of the book on If you have the time, could you tell me what (if anything) you make of it?

Ben Myers said...

Hi Thomas -- good to see that your blog is back in action! You say that string theory "is not experimentally testable -- the sine qua non of a scientific theory."

I know what you mean -- but is it really as simple as that? Aren't some theories justified merely by their usefulness and their explanatory power? So that the question is not simply whether string theory can be tested, but whether it can do anything interesting.

Thomas Adams said...

CPA -- I'm not sure what to make of Motl's comments since he alludes to intramural disputes between physicists that I’m not privy to. Also, as a chemist, I’m hardly an expert on string theory, so I cannot comment on the technical points. But it appears that there’s a fair amount of bad blood between various factions in physics community, and some disputes have turned personal. Motl obviously doesn’t think much of Lee Smolin as a scientist, and he clearly believes that Smolin’s motivation for writing the book amounts to “sour grapes”. For all I know, this may be a fair assessment, as the article made it clear that Smolin has some outlandish theories of his own, and he’s been treated harshly by the establishment. Such as that may be, it doesn’t diminish the power of his critique of string theory, which, by the way, is shared by many scientists outside of the theoretical physics community (although we chemists have always accused theoretical physicists of being totally disconnected from reality, so perhaps I’m biased).

Interestingly, Motl hurls the charge of “postmodern” at Smolin, presumably because the book explores the sociological factors at work within the physics community. This is a touchy subject among scientists, since they like to pretend that social factors never influence scientific decisions. To the contrary, they insist that the brave scientist only searches for the truth, never letting matters of prestige or career advancement get in the way. Of course, that’s hogwash. Speaking from the inside, I can assure you that science is not immune to the problems of group-think and peer-pressure. Indeed, many “lay people” would be surprised to learn how inbred certain scientific fields have become. For instance, the vast majority of new professors in my field come from a very small number of graduate schools, and many of them have studied under the same professors. Thus, the system naturally breeds a great deal of scientific conformity.

Whew!! I guess this has become a diatribe of my own. Turning to Ben’s comment…

Ben, I agree that scientists often employ models that, while not providing a compete account of reality, have considerable value due to their explanatory power. And there’s no doubt that string theory is very interesting and imaginative (that’s why it has caught the attention of many scientific popularizers). The question, though, is whether an “explanation” that requires faulty premises is still an explanation. String theory isn’t merely making a few simplifications in order to arrive at a satisfying model. On the contrary, it is inventing dozens of dimensions in order to make reality “work” on paper. That’s not a model, it’s a thought experiment.

Also, as the article mentions, string theory has not displayed any predictive power. In my opinion, a truly successful theory or model must have predictive, and not just explanatory, abilities. But this gets us back to the question of testability. Does string theory predict something usual that we can then go and verify? Apparently not. Thus, there’s no “point of contact” between theory and reality.

Andy said...

String theory is interesting in as much as it seems to be supported by the mere fact that if the suggested hypothesis are correct then the math works out. Wasn't the same true of the cycles and epicycles of pre-Copernican cosmology? But on the whole I think science will take care of itself in the long run as someone comes along with a simpler mathematical explanation, as Kepler did, that's obviously better.

What troubles me is the impact of these things on the culture. We're about 100 years past the point where even reasonably informed outsider can even do the math, to say nothing of understanding how it corresponds to reality. So now the model seems to be to just accept that "scientists have proven X". Maybe that's been the model since the Enlightenment. It just annoys me when people accept popular reports and interpretations of cutting edge science as established fact.

Ben Myers said...

Thanks for your reply, Thomas, which is very helpful. You're surely right that "a truly successful theory or model must have predictive, and not just explanatory, abilities."

Anonymous said...

There is no God. Done and dusted. End of.

Sam said...

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