Because String Theory hasn't delivered falsifiable predictions, yet keeps expanding to accommodate failure.

sesm 2 days ago | parent | next [-]

The word 'falsifiable' comes from Popper's criterion, which is central to scientific methodology. What it means: if theory predicts something, and later observations show that prediction doesn't hold, then the theory is incorrect.

String theory doesn't work this way, whatever was measured will be explained as an afterthought by free parameter tuning.

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ekjhgkejhgk 2 days ago | parent | prev | next [-]

What do you mean by "falsifiable"?

Do you mean that have been falsified? Of course, no standing theory delivers falsified predictions, when that happens you throw the theory in the garbage.

Do you mean that can be falsified in principle? In that case String Theory has falsifiable predictions, I gave you one. In principle, we can make experiment that would falsify special relativity. In fact, we've made such experiments in the past and those experiments have never seen special relativity being violated. The test of special relativity are the most precise tests existing in science.

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drdeca 2 days ago | parent [-]

I suspect what they mean is that there is no outcome of an experiment such that, prior to the experiment, people computed that string theory says that the experiment should have such a result, but our other theories in best standing would say something else would happen, and then upon doing the experiment, it was found that things happened the way string theory said (as far as measurements can tell).

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ekjhgkejhgk 2 days ago | parent [-]

But there are such experiments. String theory says that the result of such experiment is: Lorentz invariance not violated.

> but our other theories

This is not how scientific research is done. The way you do it is you a theory, the theory makes predictions, you make experiments, and the predictions fail, you reject that theory. The fact that you might have other theories saying other things doens't matter for that theory.

So string theories said "Lorentz invariance not violated", we've made the experiments, and the prediction wasn't wrong, so you don't reject the theory. The logic is not unlike that of p-testing. You don't prove a theory correct is the experiments agree with it. Instead you prove it false if the experiments disagree with it.

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drdeca 2 days ago | parent | next [-]

There are no such experimental results satisfying the criteria I laid out. You may be right in objecting to the criteria I laid out, but, the fact remains that it does not satisfy these (perhaps misguided) criteria.

In particular, predicting something different from our best other theories in good standing, was one of the criteria I listed.

And, I think it’s pretty clear that the criteria I described, whether good or not, were basically what the other person meant, and should have been what you interpreted them as saying, not as them complaining that it hadn’t been falsified.

Now, when we gain more evidence that Lorentz invariance is not violated, should the probability we assign to string theory being correct, increase? Yes, somewhat. But, the ratio that is the probability it is correct divided by the probability of another theory we have which also predicts Lorentz invariance, does not increase. It does not gain relative favor.

Now, you’ve mentioned a few times, youtubers giving bad arguments against string theory, and people copying those arguments. If you’re talking about Sabine, then yeah, I don’t care for her either.

However, while the “a theory is tested on its own, not in comparison to other theories” approach may be principled, I’m not sure it is really a totally accurate description of how people have evaluated theories historically.

And, I think, not entirely for bad reasons?

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ogogmad 2 days ago | parent | prev [-]

> But there are such experiments. String theory says that the result of such experiment is: Lorentz invariance not violated.

This is not a new prediction... String theory makes no new predictions, I hear. I don't understand why you need to be told this.

To your point, there exist various reformulations of physics theories, like Lagrangian mechanics and Hamiltonian mechanics, which are both reformulations of Newtonian mechanics. But these don't make new predictions. They're just better for calculating or understanding certain things. That's quite different from proposing special relativity for the first time, or thermodynamics for the first time, which do make novel predictions compared to Newton.

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ekjhgkejhgk 2 days ago | parent [-]

> there exist various reformulations of physics theories, like Lagrangian mechanics and Hamiltonian mechanics, which are both reformulations of Newtonian mechanics

You have no clue what you're talking about. Did you hear this in some youtube video and have been looking to try it on someone?

	▲	ogogmad 2 days ago \| parent [-]
		I suppose it's my bad that I've interacted with a troll that might not even be a real human being.

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drdeca 2 days ago | parent | prev [-]

It has delivered falsifiable postdictions though. Like, there are some measurable quantities which string theory says must be in a particular (though rather wide) finite range, and indeed the measured value is in that range. The value was measured to much greater precision than that range before it was shown that string theory implies the value being in that range though.

Uh, iirc . I don’t remember what value specifically. Some ratio of masses or something? Idr. And I certainly don’t know the calculation.