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human
[Harry Potter] Why does the Hall of Prophecy exist?

Other than to study the phenomenon of Prophecy fulfillment, I mean. 

The Ministry had never confirmed the existence of the Hall of Prophecy until after the place was practically destroyed. Yet, the prophecies are protected in a very unusual way. 

The only people that can remove a prophecy are the people to whom the prophecy refers. No one else can touch them without going insane (at least temporarily). Presumably the Unspeakables that work there have a method of accessing the prophecies **(please see end note before refuting this), though they cannot just waltz in and grab one. 

With all that in mind, are people (secretly) invited into the Hall to hear prophecies about them? If not, why do they have the ability to collect a prophecy that regards them? 

How do prophecies get into the Hall anyway? I've heard it said that perhaps the person to whom the Prophecy is made donates a memory to the Hall to create the record, but that does not seem right. 

Firstly, the hall was secret, so it's not like there was a standing law that said people had to report any prophecies to the Hall. In addition, I highly doubt Dumbledore would have volunteered the Prophecy to the Hall as it just doesn't seem like his style. He never put much stock in divination anyway and he only regarded the Prophecy as serious because Voldemort believed it (or more likely, since Snape had heard part of it and would obviously relay it to Voldemort, Dumbledore knew that the Prophecy would put *somebody* in danger).

In addition, Dumbledore never seemed to have a great deal of faith in the ministry and I think he would have seen it as too big a risk to have a full record of the Prophecy floating around (even as protected as it would be), after all, he kept Sybil Trewlany close to prevent her from being targeted by Voldemort. 

So this tells me that the Department of Mysteries has some method of... intercepting(?) the prophecies to store them in the Hall. 

**Yes , I know that it wasn't possible for Bode to take the Prophecy, but it defies logic that the prophecies are kept there, yet the Unspeakables have no way to study them. Perhaps it's like the magical equivalent of opening a bank vault where no one person knows the full combination, but two or more people have to enter their part of the combination in order to enter. Bode could not do it alone, and perhaps after they learned this, it was too difficult or risky to try putting 3 people, including the Keeper of the Hall, under the imperius curse to have them undo the protective enchantment.
gpt
I think it exists in order for the Prophecies to be kept closed off away from the both magic and muggle worlds. Knowledge of the future, the kind that is true and accurate, is extremely dangerous. The idea that a person could learn the existence of the Hall and try to steal their own prophecy could lead to them believing that they can change their fate. Obviously this would lead to disastrous consequences and that very person will have not changed anything about their future at all.