## Saturday, July 26, 2008

### Defining Theoretical Success

I'm clearly never going to understand string theory, but as it has no falsifiable results, I just don't see the point. Or rather, I'm unimpressed by elegance and consistency, because if you take a fixed set of phenomenon, people are smart enough to create an elegant, consistent set of mathematics to describe it. But only if it predicts something new, integrates (simplifies), or solves a puzzle. I don't know how many times I've read an economic paper that has 'rich' results because it can accommodate everything in some very complex way. If you think that math is good in of itself, this is really great stuff, but math has too many 'degrees of freedom'. Sure there are examples of neat math seeming irrelevant and then becoming really useful, but those are exceptions (Riemann spaces and General relativity). Neat math is not useful in itself, especially today when there are tens of thousands of theorems published every year.

Leonard Susskind, one of the founding fathers of string theory, is interviewed here. He is asked, "Can you cite any published results that support the main contentions of string theory?" He answers, "Yes! The existence of gravity, the existence of particles."

That's what I would call an 'in sample' result.

Anonymous said...

You sound like a high school student forced to study geometry.

String theory is a step towards a unified theory of physics. This is actually important to people who try to make Integrated Circuits (ICs) smaller (and therefore cell phones, laptops, etc).

Here's the issue: The channels (wires) in ICs are getting down to a few microns. It's near the theoretical limit for that stuff. There's a dual nature of light/EM radiation where it has property of both energy and matter. They haven't been really sure why, or explain it inside a unified theory. However, as they get towards the theoretical limit in these ICs, it is critical.

So, a unified theory (and hence string theory) might have an application ... just not useful for most people. Just like high school geometry.

Anonymous said...

Here's a source on light (and hence EM) duality.

http://nobelprize.org/nobel_prizes/physics/articles/ekspong/

Sometimes it's like a wave and there is interference from another wave. But sometimes, like in Xrays, where there is itnerference it scatters like particles.

Someone doing materials research to make ICs smaller/faster would love to understand why. String theory doesn't explain this (yet), but it might be a good tool to help explain it.

An alternative would

Eric Falkenstein said...

Seems like String theory is attractive because it could be useful, but isn't now. That sound like a science based on hope...kinda like religion.

Anonymous said...

It's always a challenge balancing the resources society dedicates to basic science research versus the \$\$\$ spent on engineering development. Although private companies are usually willing to provide the later, since it is more assured of a payoff.

I'm not sure how looking for a unified field theory, to fully explain the behavior of EM signals/particles is akin to religion. To me, it would seem the opposite. If our knowledge of how something in nature occurs, we have two choices: (1) try to explain it through better science or (2) call it magic/religion/God's Will.

Eric Falkenstein said...

The 'standard model' allready explains it, to some degree. String theory just tries to explain it with a more complicated, but more consistent theory. I think you can alway generate a more consistent theory if you are allowed to make it more complicated, so that isn't really interesting. If it explained more with less, something new, resolved a paradox, great, but it calls post-diction success, and I'm not that generous.