Think about what would happen if Dumbledore (strong wizard, has all sorts of authority) cast Finite Incantatem on his desk, and the spell doesn’t include a “do what I mean, not what I say” security feature.
There must be thousands of spells in that general area. Even if for some reason the desk wouldn’t be disenchanted (which probably it wouldn’t, else casting Finite on someone holding a filled magic pouch or near a magic trunk would be very dangerous, and someone would have mentioned that in MoR), it still probably has dozens if not hundreds of other spells, and can thousands of magic items due to recursive space folding. Even if many of those are protected against Finite, they are so many in total that it’s very likely that a lot aren’t.
Now that I think about it, casting Finite on something you don’t know about sounds just as dangerous as casting a spell you don’t know what it does. (Basically, Finite means casting the reverse of a spell.) Very exploitable unless something automagically checks for corner cases.)
Either he used a specific counter-free-transfiguration spell, in which case it wouldn’t affect anything that was not free transfigured, or he uses Finite and only puts enough magic into it to overwhelm anything a first-year student could produce.
I suppose he could have put in just enough juice to counter one spell from a first-year but not enough to counter two, but that is relying on a second layer of Dumbledore error.
That’s even assuming that Finite or Finite Incantatem can affect artifacts, which we don’t know to be true. Have we seen any signs of such?
enough magic into it to overwhelm anything a first-year student could produce
That wouldn’t be quite enough; Harry could have got someone else to help, though indeed it is unlikely.
assuming that Finite or Finite Incantatem can affect artifacts, which we don’t know to be true
You’re quite right about this. Presumably there’s some sort of “stabilizing” element for artifacts and spells that are meant to be (semi)permanent, precisely to avoid accidental Finite. (Not necessarily brute-force resistance spells, it could be just a safety thing to make sure you really want that cancelled.)
It’s clear that in Potterverse, there are at least four inputs to a spell: wand, gesture, incantation, and state of mind of caster. Killing Curse and Patronus, for instance, are quite clearly dependent on state of mind. Transfiguration also depends on state of mind, and I don’t recall any indication that there is any modification of the gesture or incantation depending on what transfiguration one intends to perform; that is determined entirely by intent. I think that it is reasonable to assume that, just as the Transfiguration spell is a “Do the transfiguration I’m thinking of” spell, the Finite Incantum spell is a “End the spell (or class of spells) I’m thinking of” spell.
“End the spell (or class of spells) I’m thinking of” spell.
This would make the most sense, of course. But remember that this thread started from the idea “what if Dumbledore mass-Finites”, i.e. without knowing what spell he was cancelling. This might work if Finite is smart enough to identify a class like “unknown spells that entered the room together with Harry in this general area”, but that’s stretching it a bit.
Also, though that wasn’t my original point, it still has the risk of very dangerous effects. E.g., if Harry had used a 1 ton stone instead of his father’s, for some reason. Or if someone else placed a dangerous transfigured item on Harry.
By the way, I just had an idea: the reason you shouldn’t transfigure living things is that they get sick and die after turning back (presumably due to DNA damage and protein denaturation, basically approximating radiation exposure). Trolls are dangerous because they self-transfigure into themselves. Now, imagine you’re a wizard strong enough to transfigure a troll, say into a gemstone on your ring. While transfigured the troll shouldn’t be able to fix itself (since it’s a stone). It might even pass most magic wards. But when you turn it back, the troll should repair itself almost instantly, showing no signs of transfiguration sickness.
Canon is rather inconsistent, as you’d expect. In MoR chapter 23 there’s this:
He’d put everything he had into the Finite Incantatem and it still wasn’t working.
Some hexes required specific counters or you couldn’t undo them, or maybe it was just that Draco was that much stronger.
Stuff like locks would obviously be protected, but Harry’s thoughts (“some”) suggests that it’s more of an exception.
Think about what would happen if Dumbledore (strong wizard, has all sorts of authority) cast Finite Incantatem on his desk, and the spell doesn’t include a “do what I mean, not what I say” security feature.
There must be thousands of spells in that general area. Even if for some reason the desk wouldn’t be disenchanted (which probably it wouldn’t, else casting Finite on someone holding a filled magic pouch or near a magic trunk would be very dangerous, and someone would have mentioned that in MoR), it still probably has dozens if not hundreds of other spells, and can thousands of magic items due to recursive space folding. Even if many of those are protected against Finite, they are so many in total that it’s very likely that a lot aren’t.
Now that I think about it, casting Finite on something you don’t know about sounds just as dangerous as casting a spell you don’t know what it does. (Basically, Finite means casting the reverse of a spell.) Very exploitable unless something automagically checks for corner cases.)
Nothing, I would think
Either he used a specific counter-free-transfiguration spell, in which case it wouldn’t affect anything that was not free transfigured, or he uses Finite and only puts enough magic into it to overwhelm anything a first-year student could produce.
I suppose he could have put in just enough juice to counter one spell from a first-year but not enough to counter two, but that is relying on a second layer of Dumbledore error.
That’s even assuming that Finite or Finite Incantatem can affect artifacts, which we don’t know to be true. Have we seen any signs of such?
That wouldn’t be quite enough; Harry could have got someone else to help, though indeed it is unlikely.
You’re quite right about this. Presumably there’s some sort of “stabilizing” element for artifacts and spells that are meant to be (semi)permanent, precisely to avoid accidental Finite. (Not necessarily brute-force resistance spells, it could be just a safety thing to make sure you really want that cancelled.)
It’s clear that in Potterverse, there are at least four inputs to a spell: wand, gesture, incantation, and state of mind of caster. Killing Curse and Patronus, for instance, are quite clearly dependent on state of mind. Transfiguration also depends on state of mind, and I don’t recall any indication that there is any modification of the gesture or incantation depending on what transfiguration one intends to perform; that is determined entirely by intent. I think that it is reasonable to assume that, just as the Transfiguration spell is a “Do the transfiguration I’m thinking of” spell, the Finite Incantum spell is a “End the spell (or class of spells) I’m thinking of” spell.
This would make the most sense, of course. But remember that this thread started from the idea “what if Dumbledore mass-Finites”, i.e. without knowing what spell he was cancelling. This might work if Finite is smart enough to identify a class like “unknown spells that entered the room together with Harry in this general area”, but that’s stretching it a bit.
Also, though that wasn’t my original point, it still has the risk of very dangerous effects. E.g., if Harry had used a 1 ton stone instead of his father’s, for some reason. Or if someone else placed a dangerous transfigured item on Harry.
By the way, I just had an idea: the reason you shouldn’t transfigure living things is that they get sick and die after turning back (presumably due to DNA damage and protein denaturation, basically approximating radiation exposure). Trolls are dangerous because they self-transfigure into themselves. Now, imagine you’re a wizard strong enough to transfigure a troll, say into a gemstone on your ring. While transfigured the troll shouldn’t be able to fix itself (since it’s a stone). It might even pass most magic wards. But when you turn it back, the troll should repair itself almost instantly, showing no signs of transfiguration sickness.
Do we have an example of Finite being used to cancel anything other than transfigurations or first-year level spells (Somnium)?
Canon is rather inconsistent, as you’d expect. In MoR chapter 23 there’s this:
Stuff like locks would obviously be protected, but Harry’s thoughts (“some”) suggests that it’s more of an exception.