And yet, the Patronus charm was unusually difficult for Hermione to master, despite her extensive knowledge of theory. I know it rubs you wrong, but there does seem to be a matter of 'feeling' magic and getting resistance or feedback when a spell is a sustained effect. There's also the special case of Harry's 'chase away a cohort of Dementors' incident that suggests that effort and force of will and/or confidence via understanding is key to making the big magic happen.

In the case Immet mentioned which I referenced, the text is infuriatingly pronoun-vague about what was merely a mist, what was being held back and why Harry was exhausted. I would argue that concentrating to sustain the part-formed Patronus was as draining to Harry as the effect of the Boggart-Dementor's attack.

 

The Patronus charm is explicitly stated to rely on emotion. Obviously it's somewhat different in that respect to a lot of other "conventional" magic, and therein lies why Harry was so good at it (his whole "heart on the sleeve" thing) and Hermione less so.

In which case, you need to explain why Harry was not exhausted by casting the Patronus Charm on those occasions where he didn't suffer from the prolonged effects of Dementors.

 

There's almost nothing to explain -
Patronus is only draining when it is actually in use, and not just cast with no danger? And the better at casting it you get, the more efficiently it uses the energy you put into the spell?

 

This argument does pretty much nothing. We have canon examples of the Patronus being cast without danger a) when danger was perceived but didn't exist (Malfoy's stunt) b) to send messages.

Regardless, I just don't think there's any traction in the "Patronus causes exhaustion" argument at all. Given that we have at least 3 canon examples of the Patronus being cast and not causing exhaustion. To continue to assert that it causes exhaustion in the face of this is just... absurd. It's basically asserting the exact opposite of what we see happening.

 

There is something that limits spellcasting, whether it is physical exhaustion, mental exhaustion or a limited amount of magic to be used doesn't really matter. A limit exists, from there use whatever you feel like using.

 

Just to clarify- Immet asked why Harry was feeling drained when practicing the Patronus with Lupin. I suggested that he was struggling and making an effort because the spell was incomplete and being resisted, so Harry had to keep putting effort into it to maintain the effect. Later in the chapter I quoted, Harry notes that the chocolate isn't taking away the empty feeling he has.

In the later books, Harry is able to form a corporeal Patronus, alleviating the need to struggle with it.

On the point of what spellwork entails beyond words and movement, Taure suggested theoretical knowledge was the third pillar, but I was contending that Hermione's studying didn't fill the gap when it came to this spell. As Taure pointed out, Harry's lack of emotional restraint was serving him in this case, as Hermione was less capable of putting the feeling behind the technique. So, his idea of theory supporting and enhancing spellwork applies to most magic, with the Patronus (and probably the Unforgivables) as exceptions.

 

I think you guys are over-thinking this. Try this one on for size:

You're Harry. You're standing there in class trying to think of your happiest memory and nothing else for an hour (or however long it took. I got the impression it was days on end of long lessons when he got back from winter vacation).

You're thirteen. You know how obsessive thirteen years-olds can get when they really want something.

Now you're putting everything into the spell, yelling it out, concentrating on a happy memory that you know isn't quite working, trying to think of something else, having a fake dementor swoop down on you time and again freaking you out every time, and failing yet again.

It's like experiencing the world's worst case of constipation, coming out of the bathroom, defeated once again.

Hell yeah he's going to be exhausted after the lesson. Damn, I'm exhausted after thinking about it. Where's my Ex-Lax?

 

Explaining the later castings of the Patronus to not be draining is easy. The process of creating the Patronus is draining, but once you have the skill to create it quickly and properly the drain is so quick and small that it is not noticeable. As such, all spells use a tiny bit of magical power but almost always doesn't use enough to tire the caster.

Just like carrying a long light pole- if you hold it in the middle and lift it properly it is easy and not tiring, but if you try to do it the wrong way by holding it towards one end or balancing it vertically then it is extremely difficult and tiring.

Using this explanation then having lots of available magic power is useful for gaining the skill required for proper casting- you can brute force your way into doing something, and by doing so get enough of an idea as to what is going on that you can get an experiential view of how to do it properly. As opposed to learning the theory and working out the correct way to do it the first time around. Those with the brute magic would be able to half-arse their schooling like Harry does and still be competent, but will never reach the likes of McGonagall or Snape.

---

But in this case, it's probably Harry just being mentally and emotionally drained rather than magically drained.

 

This is perhaps a silly question, I want an answer anyway.
We know that things can be done to ghosts, as Nearly Headless Nick was petrified by the Basilisk.
So it means that magic affects ghosts.

So my question is: can ghosts be put under the Imperius?

 

That's an interesting query that we'll probably never get an answer to. Given that the Imperius is not a projectile curse, and wouldn't simply pass through the ghost's ectoplasm, I'm of the opinion that their quasi-physical existence could at least be touched by the spell.

But then you have to ask what effect it would have. Are the minds of the dead susceptible to the will of the living?

I'd say no.

 

I always thought that was more of a product of the basilisk's stare being SO powerful and magical that it could even affect ghosts. Not that magical things affect ghosts. If you wanted to say things could affect ghosts, I guess you'd have to go under the assumption that every effect would be muted. So the imperius would just givce the ghost a bit of an urge to do something, rather than controlling them.

There could also be spells that ONLY affect ghosts, like various exorcism type things. You could also go with the magic is mysterious route, and just have certain spells work totally, some nothing at all, and some partially.

 

Another thing is that apparently the same mandrake draught that was used on the students worked for Nick too. Which IMHO is even stranger than basilisk stare or any spell effecting ghosts.

 

NO. An Imperius wouldn't affect the ghosts. The curse is like a bullet or any projectile while basilisk gaze is like nuclear radiation.

 

This. How does a ghost drink a draught?

 

It's a plot hole. Ghosts can't interact with the physical world. :facepalm

Good one @arkkitehti. Damn, your name is hard to spell and so is waiting for an update to your story you've got going on.

 

Well, they were able to move the 'petrified' Nick to the Hospital Wing with a fan, so there are some limits to a ghost's incorporeal nature, although probably none that make a whole lot of sense. As for the draught; I dunno, maybe they just sprayed it in his general direction and hoped for the best? I honestly think COS is one of the weakest books of the series on account of just how many plot holes there are. Half the story makes no sense at all.

 

I don't think it's that simple.

1) Unlike the other Unforgivables, the Imperius curse is not a projectile. It acts more like 'Legilimens'.

2) A ghost's ectoplasm CAN interact with the physical world on a minor level. It's stated implicitly that they create disturbances in fire, water, and some other stuff, that they can be moved by wind, and that their ectoplasm is cold to human touch.

Since the basilisk stare 'petrified' the ectoplasm, the magic of the imperius would likely touch the ectoplasm as well. Would it have any effect? Probably not. While the magic is portrayed by the body, the Imperius curse acts first and foremost on the mind... and a ghost's mind doesn't exist on any physical plane.

Edit: Ghosts make a bit more sense if you think of ectoplasm as being made of magical low-density plasma (yes, that is as stupid as it sounds).

 

A good rule of thumb would be to have spells work 10 times weaker on ghosts than on humans.

 

Wasn't Nick was able to affect a cabinet or something to stop Harry from getting caught by Filch.
Also, didn't the ministry have spells or something that they used to stop Myrtle from haunting Olive Hornby.