If you have read Smolin’s and/or Woit’s books arguing against string theory then please read Duff’s response here.
Duff’s “String and M-theory: answering the critics” is quite accessible and does a good job explaining why people are interested in string theory, both from a physics and mathematics point of view. One major point he makes is the unfair coverage of “anti-string theorists” and works that are wrong.
For example, Lisi’s theory of everything based on \(E_{8}\). This theory is mathematically wrong, it does not describe the correct matter content of the universe. Also, the use of the exceptional groups in theories of everything, including string theory pre-dates Lisi’s work. I would say that the media and the “blogosphere” was too quick to hail Lisi’s work and too slow in pointing out the errors.
Duff also points out how quickly the attacks on string theory become personal attacks on string theorists.
Is it important that the general public has a reasonable understanding of string theory and supports such reserach?
I would have to say yes.
Not that science or mathematics is a popularity contest that will be won via the general media, it will be won via peer-reviewed papers. However, the general public pays for almost all fundamental science research and thus it is vital to keep the public on board. There will always be speculation, disagreements and conflicting points of view in science at the frontiers of our knowledge, but this should not devolve into personal attacks. This only weakens the position of science in wider society.
String does have many attractive features and seems to be our best hope at understanding the Universe. The best response to the critics is come up with an alternative!
Tthat is a bit biased in reverse. String theory has done marvelous things for algebraic geometry, serving as a superb conjecture maching.
But it has failed completely to generate any new physics. No one has yet succeeded in clearly defining what string theory — as honest string theorists will admit (see for instance Briane Greene’s latest book). String theorists have done a great disservice by writing books for a general audience that greatly overstate the accomplishments of string theory and the current state of understanding. “Just plain dishonest” is a fair characterization of several, The Cosmic Landscape by Susskind being one particularly egregious example.
Yes, string theory should be pursued as a research avenue. But it should not be pursued to the exclusion of everything else. To the challenge of “come up with an alternative” I would resppond “make a testable prediction.”
I don’t know a damn thing about any of this but I like watching it unfold. It really brings into question what we define as science in my humble (and I do mean humble) opinion.
It’s also interesting that a theory can provide no useful results [yet] in the field it was originally meant to apply to but can have far flung implications elsewhere that are useful.
For example phlogiston theory was a terrible farce but mass measuring devices saw great improvement during the period when people were trying to chase down the phlogiston.
Even if string theory doesn’t turn out in any way shape or form it may not have been time wasted…
DrRocket: You make some good points. No one really knows how to define string or M-theory in a mathematically rigorous way. This is not special to strings: quantum field theory generally has no well posed definition. That is apart from very special cases like 2d conformal field theory or topological field theory. Thus, by itself this does not rule out the usefulness of string theory in physics.
What I will definitely agree with is that the popularisation of string theory has overstated what string theory has achieved today, specifically as a unification scheme. The early hopes of string theory have not been realised and one can legitimately ask if they ever will be. However, the attractive features of string theory certainly motivate further study. To date string theory (in whatever guise) is the only finite perturbative theory of quantum gravity “large enough” to contain the standard model.
String theory offers a nontrivial and very attractive generalisation of point particle theories.
Of course, strings and branes should not be the only things studied in relation to unification and quantum gravity. The claim is that to date strings seem to be the best hope. I would very much welcome another framework as ambitious as string theory.
Thank you for your input, always valued.
mississippichem: “Even if string theory doesn’t turn out in any way shape or form it may not have been time wasted…”
Very pessimistically, string theory has been a great tool in algebraic geometry and topology. String theory has motivated several constructions in geometry like Courant algebroids and generalised geometry. The small scale structure of space-time according to string theory should have a noncommutative element, this motivates NCG, though more general arguments also suggest this. Mirror symmetry and Gromov-Witten invariants all have their conception in string theory. The list goes on and I am sure will continue to grow.