I have a serious issue with Harry Potter and the Philosopher Stone. No, I will not tell you that I find it a bad book, on the contrary it’s in my opinion a well-written book with a sensible plot. My issue is with the choices made by professor Dumbledore and Nicholas Flamel.
In PS we first encounter the philosopher stone when Hagrid collects it from Gringotts, though at that point the book the reader is unaware of its importance in the remainder of the book. Shortly before we learn from Hagrid that Gringotts is the safest place next to Hogwarts. Apparently there’s a reason to move the mysterious object from the bank to the school, and rightly as it turns out that only hours later there has been attempt to break into that particular vault.
At the end of the book will learn that it was professor Quirrell, who interestingly was employed as the defense against the dark arts teacher that year, who wanted to steal the stone for his master Lord Voldemort. After Harry defeats Quirrell, Dumbledore informs him that the stone has been destroyed – after having consulted Flamel.
We can make a few observations. First it is clear that Nicholas Flamel and his wife are at peace with the idea they will die. Secondly that the stone could be destroyed in no more than a few days. These observations raise some questions.
I do not believe that Flamel suddenly changed his mind about extending his life, just after Voldemort failed to obtain the stone. It’s, in my opinion, more likely that he and his wife had discussed the issue long before.
Given that Dumbledore and Flame decide to move the stone from Gringotts to Hogwarts, it’s clear that they are aware of Voldemort’s plans to get his hand on it. The question is then why the stone was not destroyed once Hagrid took it from the bank? After all, its owner was at peace with his death, so their was no real reason to preserve it.
If the stone had been destroyed at the beginning of the book, it would have saved Dumbledore a lot of trouble. As long as it was located at his school, Hogwarts was a target of Voldemort and his associates and hence a threat to the welfare of the students and staff. There should be no doubt that Quirrell and Voldemort were willing to use all violence necessary to get the stone.
My opinion is that Dumbledore could have easily prevented the events in PS, just by destroying the stone sooner. This unlike the events in the other books. In Chamber of Secrets, the sequence of events were set into motion by Lucius Malfoy who wanted to get rid of both Arthur Weasley and Dumbledore by making the former’s daughter to reopen the chamber of secrets. In Prisoner of Azkaban it Sirius Black was triggered to escape after learning that the Weasleys had won the lottery and Peter Pettigrew was living with them. And in Goblet of Fire no one was expecting Voldemort would use the Triwizard Tournament to get hold of Harry in order to use his blood in his rebirthing process.
In none of these books Dumbledore could have intervened beforehand. Only in the Order of the Phoenix he could have influenced the events significantly, and in OP things were not as clear as they were in PS. So a mistake was easy to make, but the evidence shows that Dumbledore was perfectly aware who wanted to steal the stone and why.
We can rule out the idea of hiding the philosopher stone in Hogwarts was just a mistake. All evidence from PS points to the idea that Dumbledore intended Harry to get involved. We know from OP that the headmaster was perfectly aware why Voldemort wanted to kill Harry at age one, namely because Trelawney had predicted Harry was the one who would defeat him.
It’s likely that Dumbledore either wanted to know whether Harry was up to the job or to train him for his ultimate job: finishing Voldemort once and for all. By allowing Quirrell to try to steal the stone and having Snape playing his part, he would trigger Harry’s interest to go after the stone himself.
The best evidence for this hypothesis is the mirror of Erised. We know that the stone was hidden in this mirror an could only be retrieved by one who wanted to find the stone but not to use it. Though the stone had been at Hogwarts since the previous summer, the mirror was outside the place guarded by Fluffy.
And Dumbledore knew Harry had found the mirror on his nightly adventures. Nevertheless he did not punish him for being out of bed at night. Instead he explained what the mirror was and urged him not to look for the mirror after it was moved to another place.
My conclusion is that the only logical explanation of the events in PS is that Dumbledore wanted Harry to get involved somehow as part of his education. Otherwise the immediate destruction of the stone would be the more sensible option.