Stand to Reason is some sort of Christian apologetics organization that I don't know much about. They have this program for high school students where they come up to UC Berkeley and meet godless university students, presumably to "inoculate" them. They did it last year, and it was all quite civil. I didn't blog about it probably because nothing piqued my interest. They're doing it again tonight, but I probably won't blog about it. In fact I might not go at all, because I'm feeling a little sick.

But I was amused to have a glimpse of their YouTube channel. For fun...

The main problem with this video is... who the hell claims that quantum mechanics casts doubt on the laws of logic? I'm not sure if he actually met an atheist who said that, or if he misunderstood something an atheist said, or if it's made up from whole cloth. The rest of the argument is well-reasoned enough, but he kind of missed the crucial step of citing his opponent.

Also, while it is true that we shouldn't be dazzled by complicated jargon, this is only heuristic reasoning. Clearly there exist valid arguments which are difficult to understand and involve lots of jargon! One possible resolution is to ask an expert. As a physicist, I can tell you that quantum mechanics does not cast doubt on logic, and does nothing of the sort.

## Friday, March 9, 2012

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## 6 comments:

Well, all depends on which interpretation of QM you subscribe but if you adhere to the Copenhagen Interpretation you will get some stuff that are not logical. For example that a cat can be at the same time dead AND alive. Or that consequences can arise without causes (non-determinism).

The guy in the video said something similar. But that's not right at all.

Saying the cat is "dead and alive at the same time" is just the best way to explain QM to people who don't know the first thing about QM, and does not actually reflect any logical contradiction. Furthermore, this "problem" exists in the MW interpretation as well.

I am not sure if QM has uncaused consequences (since the very idea of causation is problematic on the QM level), and in any case causation is not a law of logic.

Regarding the Schroedinger Cat, it illustrate the superposition principle. And this contradict logic because you cannot be at the same time A and non-A (A bar).

To have something without cause is illogical for many people(including me).

"And this contradict logic because you cannot be at the same time A and non-A (A bar)."The cat is not "A and not-A". It is in a superposition state. It is not in a not-superposition state.

"To have something without cause is illogical for many people(including me)."It does not make sense to say something is illogical "for someone". It's illogical or it isn't. I do not believe you can logically prove that all events have causes, but if you think there is a proof, by all means present it.

A superposition state is precisely to be in two states at the same time. It's to be in the |Cat is dead> + |Cat is alive> state. Now if you set |Cat is alive>=|A> then, using the rules of QM, |Cat is dead>=|non-A>. Therefore there is a contradiction.

If there wasn't any contradiction, then Schroedinger Cat wouldn't be a paradox.

I cannot prove that all events have a causes because it's an axiom, a postulate. Axioms or postulate don't need proving.

If we take the statement "A and not-A", where A is some proposition, then it is a contradiction. But if we take the statement "The cat is in state |A>+|not-A>", that is not a contradiction, because here, A is not a proposition. A is just a quantum state.

If we take the statement "The cat is in state |A>", then this statement is simply false, and its negation is true.

"I cannot prove that all events have a causes because it's an axiom, a postulate. Axioms or postulate don't need proving."Well if we reject that particular axiom, it obviously doesn't lead to the breaking of the rest of logic, as the video has claimed.

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