Is String Theory Really a Scientific Theory?

vk38 writes, "The New Yorker is running a story on whether String Theory is really a scientific theory or just an abstract exercise in math designed to churn out papers and Ph.Ds for the established academics. The article reviews two current books, by Lee Smolin and Peter Woit, laying out the case against string theory." From the article: "Dozens of string-theory conferences have been held, hundreds of new Ph.D.s have been minted, and thousands of papers have been written. Yet... not a single new testable prediction has been made, not a single theoretical puzzle has been solved. In fact, there is no theory so far — just a set of hunches and calculations suggesting that a theory might exist. And, even if it does, this theory will come in such a bewildering number of versions that it will be of no practical use: a Theory of Nothing... String theory has always had a few vocal skeptics... Sheldon Glashow, who won a Nobel Prize for making one of the last great advances in physics before the beginning of the string-theory era, has likened string theory to a 'new version of medieval theology,' and campaigned to keep string theorists out of his own department at Harvard. (He failed.)"

Comments

Neither Proved Nor Disproved

[eldavojohn]

String theory is a scientific theory that has neither been proved nor disproved to my knowledge.

I could speculate all day on whether or not it is fact but from what I've read, I will make a few statements. It seems that string theory was invented to satisfy some things we could not explain. This doesn't mean it's wrong or right although some people will contend that it is most probably wrong.

As the summary points out, few (if any) of String Theory's propositions can be tested or even observed. So it is simply an unknown right now. We cannot measure the proposed strings so how can we prove if they exist or they don't? We simply can't yet.

A good analogy would be Bohr's early assumptions about the atom. They were wrong but they were a step in the right direction. In hindsight, we see this now but we don't know what the future holds for String Theory. I'm just glad there are people out there thinking outside the box.

Do not fret, however, as scientists have been very resourceful at proving/disproving theories. I submit, for example, the exercise of determining the diameter of the building blocks of matter. Scientists had the idea to fill up one cubic milliletre of oil and dump it on top of a trough of water with a roller across the top. As the oil spread out, they moved the roller further down the trough. Once they started to see non-reflective parts of the water, they moved it back until they agreed the oil was completely spread out to the best of their abilities. Using this area, they determined how thick a molecule of oil could be without precision tools!

Similar ingenious tests have been devised to easily find the diameter of the earth at sunset on a beach with a yard stick or ruler.

So even though we may never be able to measure these strings, there are still some options left to explore to record properties that may prove/disprove their existence. We're merely in the very early stages of the scientific process.

Let us be excited about String Theory, even if it is wrong it sure is interesting. Nothing's wrong with a scientist who dreams, is there?

Re:Neither Proved Nor Disproved

[wirelessbuzzers]

You're right: string theory is not a scientific theory. It's a mathematical theory. That is, it's a collection of mathematical axioms and related proofs (and an extremely unpleasant one, according to a physicist friend of mine).

String theory does provide a model of physics. That is to say, if you set the parameters right, you get something that looks kind of like quantum field theory (which, by the way, is also a mathematical theory in addition to a scientific one). Unfortunately, the math is too hard to deteremine how they differ, and even once a determination is made, string theory has a lot of parameters which will have to be set before real predections are possible. Note that quantum field theories are testable, but only barely. For instance, Howard Georgi's "representations of SU(5)" theory was disproved by experiments in proton decay.

Finally, once string theory does make real predictions, they will be hard to test. In particular, they are likely to require enormous amounts of energy, and accelerator experiments can take years to run and analyze. So it will be a long time yet before string theory becomes scientific.

Re:If it's not testable it isn't science.

[Chris Pimlott]

I love it how this happens; whenever there is a discussion about whether something is or is not a theory, or isn't actually science, the Science People always piss of the Philosophy Poeple because philosophy always gets used as a dumping ground for everything that starts out with "what if..." but doesn't quality as science. "Damn it guys, we have rules too, you know. Stop sending us your trash!"