There seem to be two ways of taking memory out of the mind in Harry Potter

One is what Prof. Slughorn did, that is, give Harry a copy of his real memory of telling Tom Riddle about Horcruxes. It is not explained directly in the book that what Harry got was a copy and not the real piece of memory in his mind, but I think that much can be implied (since Prof. Dumbledore has a tampered copy of the same thing, and prof. Slughorn still seems to retain the original memory with him, showing that it is possible to make a copy. There is no reason for him not to give Harry just a copy as well)

Another seems to be what Professor Snape did; remove his memory of having insulted Lily into the pensieve so that if Harry accidentally breaks into his mind during legiiimency class, he won't be able to see that part of Snape's mind. Again, it isn't directly explained if what Snape removed was just a copy or the real thing, but I think it can be implied from the narrative it was the real piece of memory from his mind.

So in effect, is that memory now gone from his head?

Does this now mean Snape does not have any recollection of that event what-so-ever? If someone were to tip the contents of the pensieve away, or in some other way bottle it up somewhere else so that Snape cannot take it back, he will never know it had ever happened? Once he takes it out and puts it in the pensieve, is all that he knows now is that he has pulled out some memory from his mind and needs to put it back later?

  • Just watched Goblet of Fire, where Dumbledore told Harry it would be best to forget a dream by putting it in the Pensieve
    – user47208
    Commented Jun 21, 2015 at 0:34

2 Answers 2


I think the answer is in your own question, though frankly JKR's wording is imprecise enough that it can be parsed in different ways.

  1. First, it's clearly possible to create a copy of the memory, as Prof. Slughorn illustrated in your question's reference (as he retained the memory after giving it to Dumbledore, since he could give another copy to Harry as you noted).

  2. Second, it's possible to completely remove it, as Snape done (though it isn't 100% clear from canon that this is different from what Dumbledore did).

    He turned around. The light was coming from the Pensieve sitting on Snape's desk. The silver-white contents were ebbing and swirling within. Snape's thoughts . . . things he did not want Harry to see if he broke through Snape's defences accidentally . . . (OoTP)

    However, it's only Harry's guess (and ours) that this was what Snape was doing (completely removing the memory)... it's a good guess, but not 100% certain proof.

    NOTE: We also don't know if 100% of the memory was removed, or if a "summary" of it remained - see below. Most logically, whole memory.

  3. Third, it's seemingly possible to remove the main part of the memory while leaving the stub of it (or a summary), as Dumbledore seems to have done with many memories he showed Harry.

    'This? It is called a Pensieve,' said Dumbledore. 'I sometimes find, and I am sure you know the feeling, that I simply have too many thoughts and memories crammed into my mind.'

    'At these times,' said Dumbledore, indicating the stone basin, 'I use the Pensieve. One simply siphons the excess thoughts from one's mind, pours them into the basin, and examines them at one's leisure. It becomes easier to spot patterns and links, you understand, when they are in this form.' (GoF)

    Dumbledore seems to explicitly tells Harry that one of the purposes of storing memories in the Pensieve is to NOT have them clutter the brain ("too many", "crammed", "excess"), meaning that his method removes most of the memory (I see this option as analogous to moving a large file to offline backup storage and leaving the synopsis/summary on PC).

    However, it's possible to interpret what he said differently, based on the next statement; that is may be the thoughts aren't 100% removed, and merely copied, to be able to do pattern analysis. I find that to be less likely based on the wording, but not 100% certain to be wrong.

    NOTE: I make a conjecture that he retained at least a summary, as he KNEW what those memories were about, without re-viewing them - as when he was showing Harry specific memories of Voldemort's past in HBP. But again, this is a guess, albeit a good one.

  • Unless, of course, Dumbledore removed the memory and then watched it so that he could remember the gist of it in a smaller package...
    – FuzzyBoots
    Commented Mar 22, 2014 at 22:18
  • How would removing them for storage help? If you remove the memory, and then view the memory in the Pensieve, you would presumably remember watching it. So how is that different from just keeping the memory?
    – KSmarts
    Commented Dec 29, 2014 at 16:02
  • @KSmarts - multiple options for that. For one thing, what you view and retain is probably a significantly smaller slice of the original memory. Commented Dec 29, 2014 at 16:25
  • I might have forgotten something, but is there some indication that putting a memory into the pensieve removes it from the head? I always thought of all of them as copies, and that Slughorn just reprogrammed his a bit.
    – Misha R
    Commented Jun 21, 2015 at 1:40
  • Just based on Dumbledore’s comments from Goblet of Fire (quoted above), I’d guess it’s like taking notes at the weekly staff meeting.  At the end of the year, you’ll probably remember key points like major go/no-go decisions, policy changes, and project success/failure/problems.  But it might not be until you review your notes that you notice that, almost every time Alice spoke, Bob supported her position and Charlie criticized her. Commented Aug 7, 2015 at 22:13

How removing a memory into the pensieve works is when a person of magical ability is willing to, they will cry and in their tears is a memory.

  • If you dump a memory into a pensieve it will suck you into the memory to a mental extent as shown by Harry and Dumbledore in the Half Blood Prince.

  • It is technically possible to give a copy of a memory (as displayed by Slughorn in Half Blood Prince) and when a person is dying they could choose to give away there memory by crying as shown by Snape in Deathly Hallows.

  • Most likely people can avoid giving there memory through occlumency as happened in Half Blood Prince when Slughorn gave a modified memory to Dumbledore.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.