The Sorcerer's (Philosopher's) stone was moved from Gringotts to Hogwarts because Dumbledore wanted the stone to be better protected. In Harry Potter and the Sorcerer's Stone however, Harry, Ron, and Hermione, three 11 year-olds, manage to get through seven magical obstacles designed to protect the Sorcerer's (Philosopher's) Stone.

If it was possible for three first year kids to get through the obstacles, then how was the Stone well protected at at all. Did Dumbledore really expect that the teachers' defenses would work against Voldemort?

  • 103
    Don't forget, Harry has the title character advantage on his side. Commented Jul 14, 2014 at 20:41
  • 4
    A bit like the way that people somehow always end up defending against James Bond using beautiful women, fast cars, parachuting sequences, drinking contests, fistfights, etc. That'll work, gets him right outside his comfort zone. A less perfectly capable protagonist, with less benefit of dramatic irony, wouldn't hit the sequence of X's on the stage floor that takes them smoothly through the mayhem and would be defeated. Commented Jul 14, 2014 at 23:49
  • 9
    What is this "Sorcerer's Stone" of which you speak?
    – Pharap
    Commented Jul 15, 2014 at 6:57
  • 7
    @Pharap In the EU it was called Philosopher's Stone, but AFAIK the producers thought this reference would fly over the heads of the american audience, thus they renamed the book/movie to Sorcerer's Stone.
    – zovits
    Commented Jul 15, 2014 at 9:51
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    @zovits which annoyed all of us who knew what the "Philosopher's Stone" was, but had no clue what the "Sorcerer's Stone" was.
    – rcollyer
    Commented Jul 15, 2014 at 14:55

8 Answers 8


Let's step through all the obstacles.

  1. Idiot Test

    The door was locked and required Alohomora.

  2. Fluffy

    This giant, three-headed dog fiercely guarded the trapdoor leading into the actual chamber. I suppose that it would be possible to fight your way past it, but it was such a confined space and the dog was so big that it would be nearly impossible. Even for someone like Voldemort, I suspect that it would be difficult to kill Fluffy without waking up the whole castle or alerting the staff to his presence. The gang (Harry, Ron, Hermione) was able to get past Fluffy because they knew that music would put Fluffy to sleep.

  3. Devil's Snare

    Designed to kill anyone who landed in it, the Devil's Snare was a very clever means of thwarting thieves. One can't fight their way out of it, they have to use a spell. Knowing that Devil's Snare doesn't like heat probably isn't common knowledge in the wizarding community. But due to the fact the Hermione pays attention in herbology, the group can move on.

  4. Key Room

    Filled with flying keys, this room will stop anyone from advancing that can't find the key to the door. Good thing that the group had a quidditch prodigy with them to help them catch the key.

  5. Giant Chess Set

    The only way to move on here is to checkmate the enemy king. Because Ron managed to win against the chess set, it is safe to assume that the other side was not really playing to win, but rather seeking to divide any groups that had made it this far. Or Ron is really good at chess.

  6. Troll room

    In all honesty this isn't a very good obstacle. If you already got past Fluffy then the troll shouldn't be that big of a problem. This is probably by professor Quirrell's design because he wanted to eventually steal the stone for his master. Although if it wasn't already knocked out then Harry and Hermione would've had quite a problem on their hands.

  7. Potion Room

    Containing seven unlabeled potions, this room represents one of the hardest challenges to thieves:

    "Brilliant. This isn't magic — it's logic — a puzzle. A lot of the greatest wizards haven't got an ounce of logic, they'd be stuck in here for ever." -Hermione

    So Snape's puzzle tests something that none of the others do: that you can logically work through situations. This obstacle also divides groups up because there is only enough potion to take one person through the fire (It is unknown whether Quirrell drank half the potion or it refilled itself, in either case it was still a small vial). Because Hermione was there Harry was able to go on (not that he wouldn't be able to solve it on his own, but it certainly have taken a while).

  8. The Mirror of Erised

    One of Dumbledoe's more brilliant ideas, as he puts it, is to not allow anyone who wants to use the stone to have it. The only way to get the stone is to see yourself possessing it in the mirror. This is what makes the stone very, very well protected. Anyone that wanted to use the stone for their own purposes simply couldn't have it.


The stone is in fact very well protected. The group had a very specific set of skills that allowed them to advance as far as they did, and because Harry had no selfish intentions, was granted the stone.

  • 17
    And let's not forget - Gringott's got broken into just after the stone got transferred, so at the very least Hogwarts security was that much safer.
    – Zibbobz
    Commented Jul 14, 2014 at 20:13
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    Obstacle 0: Hogwarts. To even get to the entrance, the person would need to be able to get into the corridor unnoticed.
    – Justin
    Commented Jul 14, 2014 at 21:20
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    To expand on Quincunx's answer.. Not only did they have to get to the corridor.. They have to get into Hogwarts itself, what was VERY well and subtly protected. V managed to find a sneaky way in, but getting into the school, once the staff was alerted, was a non-trivial problem.
    – K-H-W
    Commented Jul 14, 2014 at 22:17
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    Except for the last one, those all look awfully like 'security by obscurity' to me. Great for presenting the heroes of the story with a challenge that's interesting to watch and/or read about, not so much for actual security.
    – valderman
    Commented Jul 15, 2014 at 9:52
  • 5
    @trysis Only in the movie.
    – BitNinja
    Commented Jul 15, 2014 at 17:57

I think they were reasonably secure.

The Mirror of Erised alone is probably sufficient, but I think the others are also stronger than you give them credit for. Here’s my breakdown:

  1. Fluffy and the trapdoor.

    Larger creatures tend to be harder to attack. (Dragons and Blast-Ended Skrewts are a particular extreme.) Most people would probably lack the strength to stun or incapacitate Fluffy, so unless you killed him (also hard) or knew about the music, I think he’d be fairly hard to get past. He also serves as a useful deterrent to wayward students.

    Also worth noting that while Voldemort at full strength could probably kill Fluffy with ease, Dumbledore knows from Harry’s encounter in the Forest that Voldemort is severely weakened. He probably supposed as much when designing the defences. Many of these defences would crumble at the hands of Voldemort at the height of this power, but that’s not who Dumbledore is trying to defend against.

  2. Devil’s Snare.

    For this obstacle, you need to recognise the plant and know the counter-measure.

    Both Ron and Harry attended the same lessons as Hermione, but neither of them recognised the plant, nor knew the solution. When most people are faced with a dangerous situation, they panic (just like Ron does) – this is actually quite a clever defence, because panicking will just make things worse.

    Also, how much do you remember from when you were in school at 11? It’s probably not as much as you’d like to think.

  3. Flying keys.

    Even with a broom, it’s going to take a while to catch the key. Remember that in the books, the trio use a pincer movement to hone in on it:

    “We’ve got to close in on it!” Harry called, not taking his eyes off the key with the damaged wing. “Ron, you come at it from above – Hermione, stay below and stop it going down – and I’ll try and catch it. Right, NOW!”

    An individual acting alone would find it substantially harder to catch the key, and anybody who ventured down in a large group would probably be thinned by the next obstacle.

  4. Wizarding chess.

    I think this serves two purposes: to slow you down, and to divide a group of attackers. It does both quite well.

    Chess is generally not a fast game: rushing causes mistakes. If human lives are at stake, this is a poor approach. More on time in a minute (pun intended).

    If every person in your party has to replace a piece, then it’s more likely that one or more of them will be injured or killed in the course of the game. This reduces the advantage of numbers as you advance into later chambers, and may have an emotional impact on the group (witness Hermione’s distress at Ron’s injury).

  5. Mountain troll.

    Like Fluffy, this is unlikely to yield to brute strength. Unless you know about trolls in particular (or have an invisibility cloak, perhaps), I don’t see the average person getting past this easily.

  6. Logic puzzle and potions.

    As Hermione explains, this plays to a particular weakness of many powerful magicians:

    “Brilliant,” said Hermione. “This isn’t magic – it’s logic – a puzzle. A lot of the greatest wizards haven’t got an ounce of logic, they’d be stuck in here for ever.”

    Even those with some modicum of intelligence (like Hermione) will be slowed down while trying to work out the clues, and you’ll be careful because your life is at stake.

  7. The Mirror of Erised.

    This is easily the strongest obstacle (although we don’t know what was guarding the Stone before the Mirror). Despite his prodigious skill, Voldemort seems completely baffled. Had Harry not turned up, he could have taken a very long time before he got to the Stone.

    Dumbledore sounds particular proud of this invention:

    “It was one of my more brilliant ideas, and between you and me, that’s saying something. You see, only one who wanted to find the Stone – find it, but not use it – would be able to get it, otherwise they’d just see them- selves making gold or drinking Elixir of Life.”

    I think the Mirror would make him confident in the Stone’s safety.

I’d make a few other observations:

  • Even if they don’t keep an intruder out, they still slow them down.

    The keys, chess and logic puzzle would all take significant time to get past. All of this gives Dumbledore time to be notified of the intrusion, and move to engage or hinder the would-be thief.

    Even when he’s diverted to London, Dumbledore is still able to arrive in the final chamber shortly after Harry. Had Harry not tried to reach the Stone, Voldemort would still be attempting to break the Mirror. And if Dumbledore was in Hogwarts when the intrusion started, then an intruder would have no chance of getting through every chambers before Dumbledore arrived.

  • They require diversity of skill and knowledge.

    Yes, these chambers are defeated by three eleven-year-olds, but each one of them is necessary. Each chamber required a particular set of skills – skills rarely, if ever, found in the same person. Quirrell, who fought through it alone, had significant foreknowledge of the protections. I think a single person who went in with no knowledge of the defences would really struggle.

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    Your observations at the end really made me think: the biggest flaw in the design of the defenses was that it gave no notification on any break-in attempt. They are really useful in slowing down intruders, I guess Querrelmort needed quite some time to arrive to the last room. By that time, Dumbledore should already be waiting for him, maybe with a group of Aurors. It's strange to believe that there was no monitoring of any of the rooms. Or was it? Dumbledore finds Harry quite quickly after the events, so he might have been monitoring him the whole time. In this case, why didn't he intervene?
    – vsz
    Commented Jul 15, 2014 at 6:16
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    @vsz If Dumbledore had a back way in, in order to be waiting for the intruder, then the intruder could have just gotten in that way while Dumbledore was out somewhere and avoided all the traps. Not a good plan.
    – Izkata
    Commented Jul 15, 2014 at 23:16
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    @Izkata : unless, for example, no one can apparate inside the building except the headmaster.
    – vsz
    Commented Jul 16, 2014 at 3:02
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    So Dumbledore's comment from Prince chapter 26 applies: ‘The protection was … after all … well designed, […] One alone could not have done it … you did well, very well, Harry …’
    – b_jonas
    Commented Jul 17, 2014 at 5:40
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    I 1+ because of logic and canon, but the security was lacking if a bunch of misfit 11 yr olds can break in, ie. you have no security. I don't care if it took if it 100 of them, if some kids in their first year can break through then upgrade complexity. The security was not advanced, they used simple spells and logic. So my answer is that the security sucked.
    – Pobrecita
    Commented Jul 17, 2014 at 9:43

The challenges are fairly solid if you approach them in the way they're designed, but I don't think they're resistant to cheating.

Fluffy: This one's pretty good overall. Hard to bypass unless you know the secret, makes a good early warning for nosy students.

Devil's Snare: If the attacker can levitate and shoot fire (and what self-respecting wizard can't?), this one's not much of a hazard. However, it provides a soft landing for nosy students who jump down a trap door blindly.

Flying keys: Seems pretty difficult, unless they're a nosy student who happens to be an ace Seeker. However, a more powerful wizard could easily cheat this: "Accio Silver Key."

Wizard's Chess: Seems like a good obstacle. As powerful as wizards are, getting bludgeoned by a giant stone statue will hurt. Takes an unusual skill to bypass that an attacker may not have. Giant stone statues seem resistant to brute force.

Troll: Seems a little redundant after Fluffy, but unlike Fluffy, there's no easy way for a nosy student to bypass this. Quirrel just knocked it out with brute force.

Logic Puzzle: Three words: Flame-Freezing Charm. But if Hermione is right about wizards not having much logic, I suppose this is a good trap.

Mirror of Erised: This is the big one. A thief, by their very nature, can't bypass this. There doesn't seem to be an obvious brute-force solution, either. You need a nosy student (stopped by the troll earlier), or I guess Dumbledore himself.

So basically, we've got five obstacles that can be bypassed by nosy students or brute-forced by a stronger wizard, one obstacle which can't be passed by nosy students, and one that's totally bulletproof. So my theory is the first traps are designed to be a good adventure for a group of nosy students, while the troll keeps nosy students out of the real security system. The final challenge can actually stop thieves.

  • We actually have obstacles they are made to slow down but they always give you a way in.
    – Sulthan
    Commented Jan 19, 2015 at 23:13
  • I doubt Accio would work on the key. I'd rather think Quirrel used some stronger (potentially darker?) retrieval spell. Same for the logic puzzle. That's magical fire, Flame-Freezing won't work on it. I do think Quirrel bypassed this though, potentially again with dark magic. Maybe turned it into Fiendfire, gained control over it and told it to step aside or something.
    – Egor Hans
    Commented Jul 29, 2019 at 6:37

Most of the security was not based on the protection from the teachers. It was based on Hogwarts Castle being secure.

Hogwarts security is mentioned multiple times in the book - you can't apparate there, you can't even reach it on a broom (in the end of book 6, Dumbledore has to remove protecting spells to reach the tower). The Death Eaters couldn't get there without the vanishing cabinet.

The protection from the teachers was just an additional level of security and it was there because of the plot.

The security was silly to begin with:

  1. Fluffy - an animal, probably possible to be killed by magic. If not, it has to sleep sometimes. Using an invisibility cloak or some other magic could probably enable any wizard to pass it unnoticed. If not, evil wizard have lots of options, for example, taking someone else there and using them to lure the beast to the other side of the room. Also, someone has to feed Fluffy. Listening at the door how that one is dealing with Fluffy when bringing the food is the most simple way to learn about that music stuff. Another option would be to study books about handling this kind of animals.

  2. Devil Snare - something that everybody learns in school in their first year, so probably something pretty basic. The chance a potential attacker will know it is great. If not, fire is probably the first thing they would try. Or, they would be cautious enough not to jump blindly into nothingness - they could fly down creating light with their wand, for example. This would work much better by removing the Devil Snare - killing buglars instantly by the long fall and hitting the floor.

  3. Flying Keys - some powerful magic could probably attract the key or just break the door. Note that Dumbledore was able to get past this pretty quickly, so he had to have another key or he just used a more powerful magic. Why having the keys there at all? Why not just wear the key in your pocket instead? This is just making it easy for the buglers.

  4. Chess - why Chess? Why not an army of Chess pieces attacking anybody entering the room? Why the chess pieces were not a bit more clever? If a 14 years old boy could defeat them, what's the point? Again, Dumbledore was able to get past this room quickly, so he either smashed the pieces by magic (in the beginning of book 6 Voldemort can apparently destroy whole bridges), or he had some kind of backdoor. Allowing a burglar to pass through this room just by winning a chess game is a huge security breach.

  5. Troll - worse than Fluffy. Can be knocked out easily so also killable by magic easily. A very difficult security measure because it has to be fed. That means that someone has to go there every day and feed it (note that food cannot be created by magic). The interesting idea is whether they made the troll to learn Dumbledore's smell or whether they just knocked out the troll everytime they went to check on the stone.

  6. A very simple logic puzzle. Again, the question is why giving hints at all. Why not just keep the correct vial in you pocket and remove everything else from this room, keeping only the fires.

  7. Mirror of Erised - a psychological protection. Harry found the stone because he wanted to find it. Quirrell didn't find it because he wanted to give it to Voldemort. Frankly, this is more based on a play with words than on psychology. I don't think this is a good protection and there are too many questions involved. For example: would breaking the mirror destroy the stone? Where was the stone actually stored?

On a side note, a more direct approach would be to find Nicolas Flamel and beat the hell out of him to get a vial of the Elixir.

  • This always bugged me too.... it seems like the protection was not for the stone per se, but rather to provide decent plot line for us to enjoy
    – Abhinav
    Commented Nov 26, 2015 at 6:32
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    Hey, Magnus Carlsen became a grandmaster in Chess at age 13. Who is to say a magical 11-year-old prodigy couldn't also be good enough to beat a Chess game set up by a regular shmuck? Remember, McGonagall is not really known for her Chess prowess (though it's implied a few times she is a decent tactician/strategist); the transfigured Chess set was meant more as a logic puzzle with impressively tough transfiguration as a guard. Remember Harry tried to just pass through and the pawns drew their swords. So you either fight 16 giant magical statues or play Chess.
    – TylerH
    Commented Jul 4, 2018 at 14:25
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    "It was based on Hogwarts Castle being secure." This is IMHO main argument in this whole discussion.
    – TGar
    Commented Dec 18, 2018 at 11:29

The points the others are making are quite valid. The stone was very well protected once it was in the mirror. But no, there was a lot of risk to the stone before that point. Hagrid had the thing wrapped in paper and put in his pocket. He is not exactly the least absent minded person in the wizarding world but even if he was much more aware of his surroundings transport of an object such as this one should not have been left to just Hagrid.

These 11 year olds also managed to break into Gringotts in later movies through skill more than a lucky mixture of skill sets. This shows that the stone did have to be moved. The method of that transport was not the most secure and well thought out. A port-key waiting at the entrance of Gringotts might have been a better plan. Speed, low profile, no undo risk.

So, in conclusion, there is a lot of evidence suggesting that the security of the stone was not supposed to be unbreakable. I think Dumbledore had an ulterior motive. Perhaps to draw out the bad characters.

  • Making Hagrid the courier made sense as 'security through obscurity'. No one would expect a Hogwarts flunk-out to be transporting something so valuable. Plus he was escorting the Boy Who Lived around a bunch of school shops... anyone spying on them would think he was just protecting/chaperoning Harry in preparation for school, not carrying the most valuable substance known to wizards. He is also supremely trusted by Dumbledore; he was entrusted with transporting baby Harry once before, to the Dursleys on the night Harry's parents were killed (though with some assistance from Sirius Black).
    – TylerH
    Commented Jul 4, 2018 at 14:29
  • Agree with @TylerH on why Hagrid was tasked, plus I don't think the portkey would've been a good idea either. I doubt there isn't a rather easy way for a wizard to detect a portkey without activating it. Probably easy enough to check on a regular base. And once found, they could easily figure what the portkey is for, and manipulate it to bring the Philosopher's Stone right to their hands.
    – Egor Hans
    Commented Jul 29, 2019 at 6:51
  • Also, minor point of contention after being brought back by Egor's comment ping -- "11 year olds [...] in later movies" If the break-ins were shown in later movies (assuming you're talking about the Death Hallows movie(s)), then Harry, Hermione, and Ron were each 17 years old, not 11 years old (not to mention they were each fairly top students with perhaps some of the best direct tutelage from teachers and practicing adults throughout their formal education years).
    – TylerH
    Commented Jul 29, 2019 at 20:13

The stone was mostly not well protected.

Except for the mirror, the other so called protections are merely obstacles. Three first year students were able to get through these obstacles. So if a few first years get through, Voldemort should have no problem.

In the book Voldemort wasn't able to learn about the Cerberus, but there have to be some books that describe a Cerberus. Maybe Dumbledore removed them from the Hogwarts library, but there are other sources for books. There is the legend of Orpheus and Eurydice, where Orpheus managed to get past the Cerberus, and as many legends in the Harry Potter Universe are considered to be based on wizarding events (Flamel, Merlin, Circe, ...) the wizarding world should know more and not less than this legend.

The only real protection was the mirror.

Men have wasted away before it [the mirror], entranced by what they have seen, or been driven mad...

So Quirrell might have waited before the mirror until Dumbledore comes back, or he might have realized that it is futile and leave, but he would not have been able to get the stone.

It is interesting to note that Harry, in his misguided attempt to save the stone, overcame the only real protection and almost presented the stone to Quirrel/Voldemort. It is strange that Harry thinks that it is his task to protect the stone, and even stranger that he thinks he can stop an adult wizard. Whether the adult trying to steal the stone is Snape or Quirrell is irrelevant. The stone offers life and gold, and Harry knows that Voldemort wants the stone. So with one year magical education Harry won't be able to keep an adult from the stone by force, and someone working for Voldemort would not be stopped by the thought of hurting or killing Harry, on the contrary it might be considered a bonus. So with Harry's help, Quirrell gets around the protection of the stone.

Another problem with the protection is that the mirror is the only real protection for the stone, but we know that the mirror was inside the castle during Christmas, because Harry found it and saw his parents in the mirror. Therefor at Christmas either the stone was in the mirror without the other obstacles, or the stone was unprotected behind the other obstacles. The books don't answer this question, but either way the protection is worse than it could be.

There are some obvious improvements for the protections described in the book:

  • Don't place the key in front of the door locked by that key. Don't place brooms in front of the door to aid in catching the key. Bring the key when you want to go the the stone.
  • Don't include a riddle to explain the potions. Do not keep the potion there at all. Bring the potion when you want to go the the stone.

The conclusion is that the protection could have been better.

In reply to @TylerH "being in a locked room in Hogwarts which was not publicized by anyone"

“And finally, I must tell you that this year, the third-floor corridor on the right-hand side is out of bounds to everyone who does not wish to die a very painful death.”

This is not exactly subtle. This wasn't announced in later years, so it probably wasn't a regular occurrence before, so it draws attention. If Quirrell didn't know where to look before that announcement, now he did. Of course, he already knew because he placed the troll there.

As Fred and George have been in the Forbidden Forest before, they probably checked on the forbidden corridor within the first week, just because they were not supposed to do it.

“First years should note that the forest on the grounds is forbidden to all pupils. And a few of our older students would do well to remember that as well.”

Regarding the other part, first entering Horwarts, Quirrell already managed that part. Something was killing unicorns in the forest, the Centaurs knew that Voldemort was in the castle. So Dumbledore probably also knew, and therefor the "entering Hogwarts" part is no longer a problem for Voldemort.

Note that I didn't claim that the mirror was a perfect protection, just the only real protection compared to the others.

In my opinion a better protection would have been to keep the stone in his office, or in his bedroom in his drawer of socks.

  • Overall this is a good answer and I agree with most of it especially your obvious improvements of "don't provide solutions to your security problems to intruders", but it does gloss over the general protection of "being in a locked room in Hogwarts which was not publicized by anyone". This is like saying the cages holding gold at Fort Knox are not really that secure because it just takes someone with a little jailbreaking/lockpicking/hacking experience. But first you have to sneak into Fort Knox undetected. Also, given time, Quirrell would probably just take the mirror with him and run.
    – TylerH
    Commented Jul 4, 2018 at 14:36

The real protection was not the protection set-up by the Hogwarts Professors. I don't think Dumbledore really cared about other's defenses. He did care about securing the stone, thus he only counted on his own defense. The others must have been there for a different reason. Dumbledore knew that something was not right with Quirrell. Yet he let him protect the philosopher's stone.

The real protection was the presence of Dumbledore himself, which proved to be a great obstacle for Quirrell, so he had to be sent away. Voldemort didn't have his powers and Quirrell seemed too weak, and was no match for Dumbledore. From his conversation with Harry Potter in the end, it was quite revealing that a part of his intention was to watch Harry Potter's behavior. Let's remind ourselves that Dumbledore didn't always know about the magic at play. He needed data to study. He wanted to monitor Quirrell as long as possible to learn as much as possible from him before he was gone.

Let's be honest. Muggles like us, living in the technological age, know for sure that a powerful password protection always does the trick. The best way to have protected the stone (but not necessarily the fun way) was to have created a strong password and used all the dark-magic in their arsenal at who ever fails to provide the right password within 15 attempts, and ensuring that was no other way through. But 6 lines of defenses, three eleven year old kids can get through sounds too pathetic (even if it involved skills). But seen from a different view, it was not there to prevent everyone from getting the stone. It was only present to prevent certain people from getting their hands on it. Yes, I certainly believe that this was also a test for the students, who dared to enter the third floor- or specifically for harry potter and his friends: maybe Dumbledore also wanted to test if the Prophesy was true, and if the protection on Harry Potter given by his mother really worked.


As has been pointed out, Dumbledore's technique to require someone who doesn't want the stone, is very good, and the other tests have a good mix of strengths. Also Dumbledore seems to have had the wisdom to have an opening for what in fact happened, to happen - a very gifted group of students could survive it, and this could be a very good thing. In this case, elaborate obstacles actually served a purpose, since it was in a wizard academy and he was aware of the great importance of especially gifted pupils to the whole scheme of things.

What strikes me as particularly lacking, however, is effective alarms and backup security, though maybe this was due to an even greater level of Dumbledore's wisdom, possibly extending to the level of knowing this was best. However from a practical point of view, assuming you think that one could deal with the worst of thieves if one could catch them, then I would think one would want an alarm component of each stage, so that one could know and respond actively to the intrusion.

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