Tuesday, June 30, 2009

String Theory Thread

Pardon the pun in the title. I've seen a number of explanations on TV, as well as some science place's contest for quickie explanations, but I thought I'd go ahead and have a comment thread devoted to discussion, including going back to the basics. I do know it's not well regarded among many of my fellow skeptics as it is in the media, but I figure it's worth bringing up again, in the off chance something happened in the LHC when I wasn't looking. I like hearing about the tiny little bits of stuff the universe is made of, even if I don't understand it all.

I think it's a nifty idea, but nifty does not equate to useful or even meaningful.

18 comments:

Dark Jaguar said...

What it amounts to is a lot of conjecture and complicated math. The basic goal is an explanation that ties together all the observations of both quantum and massive scale rather than using two seperate theories that don't mesh well in the in-between areas. There are also a number of mathematical consequences.

It's true though that there's no evidence supporting it. However, that's actually perfectly fine in this case. It amounts to a hypothesis that's taken decades to form and find a means to test. Even Einstein was basically working in conjecture when he was starting out on relativity. Most of his work was in an absence of evidence and that was sought out later to verify his ideas.

This seems at odds with the idea of science being all about observation, but the key here is that in both cases there was at least an initial seed of observation, something that needed to be explained, that sent them off in these hypothetical directions to come up with possible solutions. In Einstein's case it was planets being where they ought not to be according to Newton. It's rather remarkable actually how accurate his ideas were considering he came up with a huge lot of it based on his initial assumption (later verified) of light as a constant.

Part of this does tie into his weaknesses. He was quoted once as saying that he didn't really care if his ideas were verified, they were "true regardless", and that something's truth is always knowable in your own head. This sort of thinking from an otherwise brilliant mind is what led him to completely reject quantum mechanics and struggle in vain to come up with a completely relativistic approach to the realm of the small until his last days.

At any rate, the point I make is that it's not unusual for people to wander off into the realm of pure math for a while to come up with ways the universe might work before eventually wandering back to get it tested. In this case, that's what massive colliders are for. I'm not saying that string theory is right, or M theory or anything else various physics mathematicians are working on these days, I'm just saying that it's all part of an extremely long "first step" and it's not completely worthless.

Bronze Dog said...

And that pretty well covers my current perception: It's an idea that's still being roughed out and explored mathematically so that it corresponds with all the existing data and theories. They're still looking for something "unique" to predict.

In short, for laypeople like me, it's worth keeping an eye on, but it's too early to get yourself emotionally attached or anything.

Dark Jaguar said...

Well one thing's absolutely for sure, these ideas have a FAR greater chance of being accurate than any random nonsense the woos come up with. The reason is simple, they model their math around what we already know around the universe to start with! Psychic energies, time cubes and so on fail on this very basic starting point and they just model away at random.

Lifewish said...

My understanding is... that you have to be a pretty shit-hot physicist to be able to comment meaningfully on this stuff. I'd expect at least a grounding in quantum field theory (including some of the main gauge theories).

I'm fine up to Dirac formalism in classical QM, and I used to be able to calculate paths in general relativity. I'm painfully aware how far that leaves me from cutting-edge physics.

Speaking as a skeptic, it worries me that everything I know about the subject is derived from media sources and popular science books. Not a particularly firm grounding... Does anyone else have a stronger background?

Akusai said...

What bothers me the most about string theory is Michio Kaku. Fuck Michio Kaku. He takes what is, as Dark Jaguar says, a hypothesis with a solid grounding in mathematics but no empirical data (it was decades before it was clear that ST was even testable at all) and runs around talking about it as if it were absolutely positively 100% true. He gets defensive and shitty if anyone even asks about empirical testing.

Einstein, when he published his theoretical work, would explicitly urge experimental physicists to test the predictions of his theory. Whether or not he believed in his own head that his theories were true regardless is his own problem; he understood how science worked. Kaku just runs about preaching the gospel of string theory as if it's more experimentally confirmed than fucking gravity. He isn't exactly doing wonders for the public understanding of science.

Dunc said...

As I think I've said before, it doesn't actually require any new predictions - being able to derive all of current physics from a single unified theory would be a significant step forward in itself.

Jason said...

I propose a law linking the time between the creation of a hypothesis and arrival of relevant empirical evidence, to the everyday usefulness of that hypothesis.

For example, "I'll bet this lion likes being poked with a stick! ...RARWWR!"

Dont mind me, I'm just thinking out loud.

Joshua said...

What Sean Carroll said: http://blogs.discovermagazine.com/cosmicvariance/2006/06/19/the-string-theory-backlash/

There seems to be a visceral hatred of string theory all out of proportion to what it actually is. I suspect Michio Kaku, who seems to be the target of much of the ire, is just the string theory equivalent of the guy who coined the term "God particle"; i.e., not at all representative of the attitudes held by the vast majority of people in the field, but he said some stuff in public this one time, so fuck it he's the Emperor of String Theory, ruling all his theoretical physics subjects with an iron fist.

It's science, guys. We don't know what's around the corner. I thought that was the whole point. If you look at the history of it (e.g., that Cosmic Variance post I linked), string theory has a sound theoretical basis and arose from physicists' attempts to answer questions that existing theories couldn't. We can't test it yet, in the way that we plebes used to using the word "test", but so far it doesn't contradict any of our existing physics. That's a good thing in a theory.

And if you look at the history of science, that's how the big theories in physics always start. Especially atomic physics! How many years passed between the theoretical proposal of the Standard Model and the discovery of the W and Z bosons? Nearly twenty! The top quark took even longer. Does that mean the Standard Model is "not even wrong"? No, it just means that high energy physics experimental equipment takes a long time to catch up with the theories it's meant to test.

When the LHC has been running for ten years and there's still no evidence for string theory, then we can talk about it being unscientific.

Akusai said...

Michio Kaki isn't the only one. Brian Greene does more or less the same thing. Plus I never said he was emperor of anything. And I never said string theory was unscientific, just that it hasn't been tested and there is no actual empirical data backing it up yet, so it's silly to scream its truth from the rooftops.

Dunc said...

it hasn't been tested and there is no actual empirical data backing it up yet

So (potentially) explaining the whole of General Relativity and Quantum Mecahanics in one fell swoop doesn't count for anything in your book? The "empirical data backing it up" is the entire field of known physics.

Chiral said...

The fact that no subatomic particle can be brought completely to rest, but will always possess a tiny residual movement - as verified with microwave receivers, electronic circuits, even florecent bulbs, leaves me thinking that String Theory has merit.

However, I find The 1911 Planck experiment which demonstrates that empty space is constantly bursting with activity to be of greater interest. The idea that we are (at a quantum level) constantly interacting with "empty space" is an avenue - as a sci-fi writer - I'm happy to venture down.

Oh... and I'm new here. What is a Woo?????

Bronze Dog said...

SkepticWiki has that covered, just for a quick link. Might want to look at the Respectful Insolence source they use.

Chiral said...

oh... so I'm a Woo too. :-) Cool. Because I absolutely believe in romance, chivalry, honest people and great sex and having experienced none of the above and I still hold out hope - I must be a Woo too.

Bronze Dog said...

Well, plenty of people have replicated those things extensively over the years. It's not much different than believing in the Big Bang even though I haven't personally measured the cosmic microwave background radiation.

Dark Jaguar said...

I believe in friends and laughter and the joy those things may bring, I believe in second chances and I believe in yoouuu.

Ya see there's nothing unscientific about believing in those things, we know all that stuff exists.

At any rate, I do think there's value in coming up with a unifying theory combining everything, even if it's own truth is never verified as such, the fact that what it unified has plenty of evidence means it's basically just an act of simplification.

Akusai said...

Dunc:

So (potentially) explaining the whole of General Relativity and Quantum Mecahanics in one fell swoop doesn't count for anything in your book?

No, I didn't say that, and if it came out sounding like that I apologize; my last post was short not because I was trying to be dickish or anything, but because I was typing on my iPod under time constraints, so I couldn't go into a lot of detail.

Explanatory power counts for a lot, but it doesn't equate to truth (regular old tentative scientific truth, not the eternal, capital-T kind). I think I should have been more precise and said that the specific predictions of string theory have not yet been tested. It potentially explains and unifies all of physics, but it's still potentially falsifiable.

Lifewish said...

I propose a law linking the time between the creation of a hypothesis and arrival of relevant empirical evidence, to the everyday usefulness of that hypothesis.

Counterexample.

Dark Jaguar said...

On the flip side, an alternative explanation that comes along with no evidence for it's "truthiness" that explains all the same things and is used expressely for the purpose of simplifying the math can be considered just as true as what came before, with the only difference being the origin date of the ideas. If all string theory amounts to is something that has the exact same predictions as both relativity and quantum mechanics, only it combines them into one seamless set of maths, I'd say it's still perfectly valid.