What is the purpose of the green potion?

[Jen Reese]

Eloise:
> Dumbledore tells us that Voldemort would have wanted whoever stole 
> the Horcrux to survive long enough  for him to find out how he had 
> managed the theft. Speculation amongst various posters that the 
> potion forces memories to the surface reinforces the idea of 
> interrogation, but there are a couple of problems with this, from
>  my POV.

> If Dumbledore is correct, then Voldemort needs to be aware *and 
> quickly* that the Horcrux has been taken.  If Voldemort knew that 
the 
> original was stolen (leading to RAB's death*) then either 
> a) he would have recovered  and re-hidden it or 
> b) he would be actively looking for it. 
> The latter is quite a significant thing to become aware of only in 
> the last book. 

Jen: Voldemort's arrogance is at work here, too. Dumbledore doesn't 
say "Voldemort will want to know who stole his Horcrux" 
but "Voldemort will want to know who penetrated so far into his 
defenses and why they were intent on emptying the basin." Implying 
LV is certain his Horcrux will not be stolen no matter how far 
someone penetrates, and he believes his protections are fail-safe. 

So the potion doesn't kill instantly, but either the potion or most 
likely the basin collects the intentions of the intruder, probably 
as the potion is being drunk. Voldemort assumes any person drinking 
the potion will either drink the water in the lake, maybe a fast-
acting posion, or be dragged down by the Inferi in a weakened state. 
Then Voldemort can leisurely study the basin when he next visits the 
cave.

Eloise: 
> I'm not sure I believe Dumbledore on this occasion. I believe it
> is a convenient fiction foisted on him by the dastardly author.

Jen: Hehehe-this explanation works, too.

Eloise: 
> What does the potion actually do in terms of the book?
> 1) It provides an obstacle to retrieving the Horcrux
> 2) It becomes a test for Harry's loyalty to Dumbledore
> 3) It potentially makes Harry an agent of Dumbledore's death
> 4) It produces some intriguing dialogue
> 5) It produces a Dumbledore dependent on Harry's help (and in
>    David's view thus enlightens us as to DD's greatest fear)
> 6) It complicates the issue of what exactly killed Dumbledore

Jen: There's another reason. The potion also tells us about the 
psychology of LV, his weaknesses and obsessions, as well as the ways 
he overestimates himself and underestimates the enemy. No one should 
have penetrated his defenses, no one should be willing to drink the 
unknown poison (or even figure out it needs to be drunk in the first 
place!) and no one should know about the Horcruxes. Dumbledore was 
capable of all three. Talking Harry through that potion business 
helped Harry see Voldemort isn't *only* interested in killing 
people, that he is meticulous about his protections, and that Harry 
will probably need the help of someone like a Hermione to decode the 
protections <g>.....

(The only other explanation I can come up with is that the cave was 
a trap specifically set up for Dumbledore by Voldemort. But that 
still leaves the problem of the fake Horcrux to account for. *sigh*.)

The way Dumbledore deconstructed Voldmemort's magical style in the 
cave will serve Harry in the future, I think. Hopefully JKR won't 
just drop the idea she spent so much time on in HBP, that Harry 
needs to understand where Riddle came from and how he evolved into 
Voldemort if he hopes to track down the Horcruxes. I'd find it 
disappointing if Harry *never* remembered or used what he learned in 
all the lessons with Dumbledore. 

Someone suggested on the main list maybe Dumbledore's way of seeing 
invisible magic will be something Harry realizes he can do, too. 
Maybe this skill will even be the mystery of Lily's and Harry's 
eyes? I keep thinking of that interview where JKR side-stepped the 
issue of doing magic with eyes instead of a wand:

Lizo: "Are there any special wizarding powers in your world that 
depend on the wizard using their eyes to do something? Bit like
"
JKR: "Why do you want to know this?" 
Lizo: "I just vaguely wondered."
JKR: "Why?" 
Lizo: "Well because everyone always goes on about how Harry's got 
Lilly Potter's eyes?"
JKR: "Aren't you smart? There is something, maybe, coming about 
that. I'm going to say no more. Very clever."

Eloise:
> The thing *specific* to the potion is that it evoked Dumbledore's 
> strange ramblings. ~And that Harry heard them. What Dumbledore
> says is not secondary to the use of the potion: I believe that JKR
> used the potion specifically to provide a vehicle for what he
> says. In which case the words *are* significant to future plot
> developments: they are not the memories of the Inferi, they are
> probably nothing to do with RAB (whose identity is important only
> in terms of helping Harry to find the locket). I personally doubt,
> true or not, that JKR will ever spend time exposing Puppetmaster!
> DD so his remorse over past decisions will be neither here nor
> there in terms of the plot development. Which, as all roads 
> inevitably do, leads me right back to Snape.

Jen: All that's very true. I don't like any of my roads to lead to 
Snape <g>, so here's a possible alternative.

Dumbledore's greatest fear must be important or JKR wouldn't have 
hedged about it in the interview.  I think that's what we're seeing 
while Dumbledore drinks the potion, a boggart-type experience which 
affected him severely. Wouldn't an extremely clever wizard have a 
correspondingly huge fear that something will bring down everything 
he's worked for? Something really Big. Like dying before he tells 
Harry everything he needs to know :). Maybe David's idea fits, that 
losing Harry would be his biggest fear. I'm not sure how that would 
play out in the next book with DD gone, though. Will have to think 
about this part a bit more....