My question is pretty much summed up in the title, but I'd like to add a little more to it. If all four of them had the exact same recollection of the truth (Wormtail being revealed as the true killer) - why didn't they extract their memories and put them into a pensieve?

I mean sure, memories can be tampered with, but we have learned that even skilled wizards (such as Slughorn) are not able to modify their memories without it being apparent.

It would be very hard to believe that four people, three of whom were underage wizards, were able to modify and perfect their memories to all be the exact same recollection of the events that happened in the Shrieking Shack.

So then why did they not all add their memories to Dumbledore's pensieve for the ministry to view so that Sirius' name could be cleared?

  • See also scifi.stackexchange.com/q/104675/4918 "Wizarding Court and Veritaserum"
    – b_jonas
    Jun 23, 2016 at 16:22
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    Because memories can be tampered with.
    – Valorum
    Jun 23, 2016 at 16:22
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    Because nobody told JK Rowling about Sanderson's First Law.
    – Rand al'Thor
    Jun 23, 2016 at 16:25
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    @TabithaWilson - Well, all the evidence would suggest that Slughorn was actually pretty poor at memory modification. Gilderoy Lockhart, on the other hand was accomplished at memory charms. Presumably if he enchanted them, their (false) memories would all be identical.
    – Valorum
    Jun 23, 2016 at 17:02
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    I thought that Gilderory was only good at one specific charm, Obliterate. Does he ever mention being able to completely reconstruct memories? Jun 24, 2016 at 15:51

2 Answers 2


Two reasons jump to mind.

First - time pressure. Shortly after Harry wakes up he is told they will be performing The Kiss "any moment now". Not a lot of time to convince the adults (against the word of Snape, and without Lupin, who is off being wolfy) to hold back.

"Ah, you're awake!" she said briskly. She placed the chocolate on Harry's bedside table and began breaking it apart with a small hammer.

"How's Ron?" said Harry and Hermione together.

"He'll live, said Madam Pomfrey grimly. "As for you two you'll be staying here until I'm satisfied you're ­­ Potter, what do you think you're doing?"

Harry was sitting up, putting his glasses back on, and picking up his wand.

"I need to see the headmaster," he said.

"Potter," said Madam Pomfrey soothingly, "it's all right. They've got Black. He's locked away upstairs. The dementors will be performing the kiss any moment now ­­"

Second - memories can be modified well. Dumbledore notes that Slughorn - as capable a wizard as he is - performed the modification on himself ineptly.

"Because, I think, he is ashamed of what he remembers," said Dumbledore. "He has tried to rework the memory to show himself in a better light, obliterating those parts which he does not wish me to see. It is, as you will have noticed, very crudely done, and that is all to the good, for it shows that the true memory is still there beneath the alterations.

Presumably some forgeries are (almost) impossible to detect, as evidenced by the fact that Tom convinces Morfin that he killed the Riddles.

"We have no memories to show us this, but I think we can be fairly sure what happened. Voldemort Stupefied his uncle, took his wand, and proceeded across the valley to 'the big house over the way.' There he murdered the Muggle man who had abandoned his witch mother, and, for good measure, his Muggle grandparents, thus obliterating the last of the unworthy Riddle line and revenging himself upon the father who never wanted him. Then he returned to the Gaunt hovel, performed the complex bit of magic that would implant a false memory in his uncle's mind, laid Morfin's wand beside its unconscious owner, pocketed the ancient ring he wore, and departed."

"And Morfin never realized he hadn't done it?

"Never," said Dumbledore. "He gave, as I say, a full and boastful confession."


Within the HP Universe:

1) They didn't have enough time. Sirius was already being put to death, Ron was in the infirmary, Lupin had run off as a Werewolf and Harry and Hermione were busy going back in time. There was no way they could have gotten corroborating memories from all of them

2) Sirius Black's escape from Azkaban, which cannot be denied, he did definitely do that, resulted in a death sentence for him. Even if they proved that the crimes he was imprisoned for were not committed by him, that only exonerates him from those crimes, not the crime of escaping from prison. Even though he should never have been in prison in the first place. Law is weird.

3) The whole "Memories can be modified" thing, which is possible enough that evidence from a pensieve could never be submissable to a court of law. Thinking about it, there's also no guarantee that the memories of the 4 would match, as memories really can change naturally over time anyway, so there's no way of knowing if a memory is accurate, magic modifications aside. You, reading this right now, will have memories that you might think you remember as though they happened yesterday, but there's a good chance that some of the details are incorrect and are actually being filled in by your brain. The trouble is, there's no way of knowing if the details are correct or not.

Outside of the HP Universe:

JK hadn't really thought up the idea of the Pensieve and put it into her stories until Goblet of Fire. That's why it's the first book/movie in which we see any of it.

  • Have you got any sources to back up the statement that JK hadn't thought up the Pensieve by book 4?
    – DavidS
    Jun 23, 2016 at 16:56
  • This is a fantastic answer! Jun 23, 2016 at 16:58
  • You might want to note that this answer contains an inaccuracy. In the HP world, pensieve memories are non-subjective. That means that the viewer sees precisely what happened and can also see things that the original viewer didn't see.
    – Valorum
    Jun 23, 2016 at 17:44
  • Ok, ignoring "Magic can do whatever because magic", Non-Subjective memories are impossible, memories are subjective by nature. They're just collections of sensory data bound into a single location and loosely timestamped. "Can see things that the original viewer didn't see?" Doesn't make sense, how can a memory show you anything that isn't part of the memory itself? And even with "Magic can do anything because magic", the only way it makes sense is if the Pensieve is filling in blanks and interpreting stuff, which means there's no way in hell that would be submissable, even in Wizard court. Jun 24, 2016 at 8:57
  • Unless the Pensieve had at least partial access to objective reality, in which case you'd be able to trust the details. Jun 24, 2016 at 10:29

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