This. There really is no evidence in canon to judge how good a Protego, or even magic in general, is against projectiles or explosives of any sort. Wizards certainly don't need to fight muggles in open battles to maintain their society, so there is not even any anthropic argument to be had either way.

But for what it's worth, I think that saying any half decent wizard can negate serious explosives with a simple Protego is about as sensible as saying Ron Weasley can lift Big Ben into the air with a Wingardium Leviosa. Just because magic can ignore the laws of physics doesn't mean it can't have any sense of scale at all.

 

Well, whether magic breaks physics or not...

I took particular issue with the notion that a Protego, which I don't think has ever been shown to be spherical or body-encompassing, could simply be applied before a fight and would not only remain active, but also follow your every movement, so that you could waltz about the battlefield concentrating on things like the proper rhyme and meter of a good limerick, instead of making sure you don't get blasted.

We've basically seen Protego as a sheet-shaped shield (for shoving sharply sheared shared shambling sheep and shoring short shady shantytown sheds, surely) which apparently can be propelled forward on command (as Hermione does from a Gringotts cart).

The notion that a simple Protego can be cast in such a way as to make it a weightless suit of tank armor that protects you from all angles as you move seems rather farfetched, to me.

In the end, even if the Protego is 'all that', the fact is that the average witch or wizard- Scratch that: Even the average Ministry worker, Aurors included, is so inept that a disposable shield hat purchased from a joke shop sounds like a good investment to them. :facepalm So a person capable of a Super-Protego would be so rare as to make the casting of such a spell to be a thing of legend.

Voldemort opted for a handheld, physical, conjured shield, that he would have had to position by hand, rather than the theoretical fire-and-forget Super-Protego.

So, either he couldn't do it, or it didn't exist. I could also point out that Dumbledore opted to employ animated statues for Harry's protection, rather than such a Protego... however, in all fairness, Harry was getting impossible-to-shield Unforgivables lobbed at him, so Protego wouldn't have helped him, in that case, anyway.

And, as has been stated before, bullets are one thing but bombs are another. That Protego would have to protect against everything it already does, the pressure wave, heat, chemical burns, noxious gasses, lack of oxygen, possibly radiation... and nuclear reactions, if you're a spectacularly unlucky wizard who unexpectedly finds himself within spitting distance of a nuclear warhead.

And, now is the part of the program where I (slightly hypocritically) point out that this particular off-topic tangent has spiraled beyond the bounds of this thread's purview.

 

As long as the author provides the reasoning behind a spell doing something unexpectedly amazing, I'm fine with it. Since JK Rowling just made the magic system up as she went along, you have to either ignore or explain away a bunch of story-breaking abilities when you're writing in the Potterverse anyway.

The girl who wrote Misconceptions (currently three stars in the Review Board) is either a freshman or sophomore in high school (14-16), depending on how current her FFnet profile is. That definitely doesn't read like something that would come from such a young kid. Unless one or both of them are lying, I suppose.

 

What Sesc said. It's perfectly possible for magic to have limits and yet those limits to have nothing to do with physics.

E.g. "Magic cannot reawaken the dead."

 

If magic doesn't follow the laws of physics, then the laws of physics are wrong. Systems have to be self-consistent.

 

I'm all in favor of declaring Muggle laws of physics wrong.
Especially since trying to combine the two can lead to Morrible things.

 

Are we talking about the internal consistency of magic within the context of a fictional world or are we talking about what will happen to science if magic is real?

If we are talking about the internal consistency of magic, a simple rule must apply when it comes to depicting it in your story. You must avoid the no limits fallacy as much as possible because it goes against the logical thinking process of your reader.

But it doesn't have to be completely wrong. The fact that muggle technology was created based on their understanding of physics shows us that the physicist in HP-verse must have gotten something right.

Rockets fly because the law of physics allowed them to do so. Just because wizards have the means to avoid the pesky issue of gravity does not meant gravity did not exist.

 

What, you want to marginalize Muggle stuff? Why the fuck would you want to do that? You're basically saying ~99.9% of every human on Earth is irrelevant and inferior to the other 0.1%... You don't have a single moral qualm about that? The hell is wrong with you?

*edit*

Also, I completely agree with what T3t wrote in the post below mine.

 

I meant that the universe has to be self-consistent. If magic exists in the universe, then it follows the rules of the universe (colloquially known as the laws of physics).

 

Uh no, personally I wouldn't have a single qualm about saying that. In a world where some people are born with the ability to break the basic laws that everything else in the universe must abide by, then they are inherently superior. That's not to say that non-magical people are meaningless or worthless, or even lacking in power of their own, but wizards are, by definition, superior to non-wizards in such a setting. Period.

 

Oh come on! It's far from obvious, and while it may be fine for you to say that magic breaks physics, it isn't to me, and it might not be to everyone else either. To me, saying that is a cop-out and boring.

As to the other, Harry Potter is about the Wizarding World, but you don't have to marginalize Muggles so much, either. After all, if HP were real, we'd be Muggles ourselves, and I personally would rather not be marginalized.

I honestly don't know how to reply to this. I want to say that you're a terrible human being, but as I typed that, I realized I couldn't properly explain my reasoning. To me, saying one group of people is superior to another reeks of fascism, and it's morally repugnant to me.

Sesc said he wants this discussion to end, so this will be my last post on the subject, at least in this thread. Y'all can do what you want.

*edit*

Taure said it very nicely below. That's what (I think) T3t was talking about, and what I've tried to talk about in the past, but haven't really gotten across.

 

ITT: arguments started over ambiguities like...

Physics A: an imperfect, incomplete and at times contradictory body of knowledge created by humans covering various phenomena, generally considered to be the lowest "level" of analysis possible (though some now assert information theory, or even mathematics itself, is more fundamental).

Physics B: the way the universe works.

Now, if you want to say that magic, as part of the (fictional) universe is part of how the universe functions and thus, by definition, part of fictional physics B... fine. But that says nothing about whether or not magic breaks physics A. Indeed, any hypothetical physics B which includes HP magical phenomena will break physics A. To assert otherwise is to say that HP magic is possible under our current understanding of physics (physics A) i.e. possible in the real world.

Speak for yourself, mudblood.

 

The only fascists in this thread are physics-fascists, who believe that physics by definition must describe everything in the universe.

Oh, and Sesc. Because he hates mudbloods.

 

Them you have a poor understanding of what science actually is. The study of magic itself can be considered a science.

After all, science is merely "a branch of knowledge or study dealing with a body of facts or truths systematically arranged and showing the operation of general laws".