Knowledge Of Horcruxes SPOILER

[kashlie]

I'm not sure if this is the right place, so I don't mind if it needs moving...

I am wondering about Slughorn and his knowledge of Voldemort's Horcruxes.
We know he altered his memory in the hope that no one would discover that he told Riddle about them, but this means he knows that Riddle actually made the Horcruxes and how many.
So, did he know Dumbledore was struggling to find out how many and what the pieces of soul were put in? Was he only afraid of getting in trouble for telling Riddle about the Horcruxes, or being in trouble for seemingly encouraging him to do it?
And if Slughorn knows about the Horcruxes and how many Riddle would have made, then how many other people know as well?

[mimbulus mimbletonia]

See the way I've interpreted it is that Slughorn knew DD didn't allow talk of such things, and when DD approached him (after he retrned to Hogwarts) about the memory, Sluggy felt very very bad. He guessed that Voldemort went through with making the Horcruxes and the guilt would have got to him. So I think Sluggy fobbed DD off the first time he asked, tried to alter his memory, then allowed DD access to it.

It would have been the sort of thing that he barely remembered, until DD showed an interest in it.

[Tonks]

I'm sort of with mim here. The knowledge of Horcrux information seems to be really rare, almost as if there is a taboo against discussing such information (pretty much like saying Voldemort's real name actually).. so I doubt very many people know anything about them..

Slughorn probably feels an extreme amount of guilt for providing Tom with the information that made it possible for him to become pretty darn closed to immortal. He didn't have a clue he was doing it at the time, but must have guessed that was what Voldemort had done, after learning he couldn't die and combining that with his knowledge of Horcruxes. After all, it did pretty much lead to the deaths of dozens of people - I'd supress that if I was responsible for it.. even if I never meant anything like that to happen in the first place..

I think Dumbledore knew that he had been the one to tell Tom about what Horcruxes are and the basic information about how to form them - all he wanted out of the memory was to know if Tom had given Slughorn any hint as to how many pieces Voldemort had split his soul into..

[amyleigh13]

at the end oh HBP it seems as if harrys gonna take the mission by himself, obviously he has to be the one to kill voldemort, but will he let the order of the phoenix help him find the horcruxes, and help protect him, :eek: and do the order know about the horcruxes

[Sirius Potter Fan]

I suspect that Dumbledore at least let a few of the order in on the horcruxes before his death, since he probably knew that there may have been a chance he wouldn't return from the cave, let alone what he may or may not have known about Snapes vow. so yes, I would say that at least some in the order know of the horxruxes. and no, I don't think that Sluggy really did know at the time that Riddle was going to attempt that, I think he thought it was just curiosity. And. . . didn't Sluggy say at first that he still wasn't shure which side he was on?

[Alz]

I think Slughorn thinking it was his fault that Riddle decide to take this course of action.
In essence it looks like Riddle was already curious about the Horcruxes methodology - afterall he feared death about as much as he feared Dumbledore.
I think Riddle was having issues locating the information and as such he charmed Slughorn into a position of trust - afterall we were told Riddle was quite a charmer - and then used this connection to ask for information.
Slughorn then provided more information on it.
My point here is that Riddle was the one that did the 'legwork' on this - he alone decided to get more details and then execute it on himself - the only thing Longhorn can take any guilt from is that he gave Riddle that bit more information on it.

[Fortescue]

I think Tom pretty much knew already what the Horcrux was for - it seemed his question to Slughorn was if it was feasable to make seven as seven was a much better number than one. The only thing that Tom didn't really seem to know was the spell required to make a Horcrux, and either Slughorn didn't know the answer or decided not to divulge it. Tom obviously found out this information from another source, because soon after he left Hogwarts he began making his Horcruxes.

[jburden]

It strikes me the fact that Harry and Dd are not the only ones after voldy.....

R.A.B...........


What was Dumbledore's brother name? Do we know anyone with the last name of B?

Blaise maybe? maybe not....

nevertheless....it looks like Harry and R.A.B are BOTH (if R.A.B is still alive that is) going to go after the Horcruxes.

[Snuffles]

There has been:

but this means he knows that Riddle actually made the Horcruxes and how many.

I don't think Slughorn knew Riddle was actually going to make the Horcruxes, or that he'd dare make seven of them, too. Riddle had lied so deceptively that if I were in Slughorn's shoes, I would have thought Riddle, my favorite, top-grade student, was merely asking a question out of curiousity that came to his brain while he was researching for some other project. Yes, I understand that there might be objections to this because... "Why on earth would Slughorn try to modify this memory, then? If he was only answering a student's inquistive question?

Well, as Mim have said, since Horcruxes are much of a Dark Art, telling about them to a more than capable, curious student would have been a very bad thing. Ashamed, Slughorn tried to hide this memory.

I think Tom pretty much knew already what the Horcrux was for - it seemed his question to Slughorn was if it was feasable to make seven as seven was a much better number than one.

And I completely agree with this one. Tom only asked Slughorn how it would affect the person if more than one Horcrux was made. He knew about Horcrux from the start, which is why he asked about it to Slughorn.

[Fortescue]

Something also to remember - when Dumbledore went to see Tom Riddle in the orphanage to give him his Hogwarts letter and explain things to him, Dumbledore found the box of things that Tom had stolen from the other children - they were his trophies of his conquests against the orphans.

The items in the box were enchanted as they were rustling around in the box as we saw - he had somehow enchanted those items already. Maybe the however he enchanted those items without a spell was all he needed to know to put his soul into the items he acquired later and he didn't realize it.

[Alz]

I dont think we have ever been told at what point Riddle/Voldemort became obsessed with death ... and also gave rise to him investing so much into the Horcruxes theory ...
This is telling in my world - because if we can work out at what point he became obsessed and I suppose more important what made him so 'paranoid' about mortality that he needed to invest so much into making sure he was always alive ...
I think there are many more questions to this than answers ... I wonder if we really do have all the facts to work out the answers already ...
I said all along something made Riddle obsessed with his mortality - and I dont think it was just protection for his furture planning to rule the world ...

Out there I know - but this still screams of 'time' and someone seeing forward or able to go back ... the reason for the paranoia is then simple ;)

[Fortescue]

I can only guess when Tom became obsessed over death - but it would seem it would have happened the first time he killed - probably the Riddles. At that point he probably realized how easy it was to kill someone and he also split his soul for the first time making him a bit more evil. The fact that it was easy to kill made him realize that what he did to the Riddles, someone could just as easily do to him.

[Alz]

For a more mainstream theory that works well ;)
For some reason it seems to me it was an obsession for Voldemort - it was beyond paranoia and more all out fear and panic.
I think he was made aware of his own, personal mortality and that is what fuelled his obsession to the point he was willing to desecrate his own soul in order that he wouldn't die and move further down the path of immortality than anyone else had ever been.

[Fortescue]

I guess my biggest question regarding Harry's Pensieve moment with Tom and Slughorn would be - what is the significance of the number "7"? We have not been told anything through this point in the story. There must be something that JKR has not yet disclosed to us that makes 7 a better number than 6 or 8!!

The only thing that remotely comes to mind to do with 7 is the number of Weasley children - and Harry's overhearing Trelawney talk while looking at the playing cards - she drew a 7 of spades and said it meant "an ill omen!"

Has anyone else noticed the number 7 used throughout the story? I can't think of any.

[Sirius Potter Fan]

12 has been used alot in the story, and no, I can't think of a specific meaning full use of it previously, unless that there are 7 years at Hogwarts? The thing here is that Tom thought it meaningfull. he said to Sluggy,

"Yes, Sir," said Riddle. "What I don't understand, though -- just out of curiosity -- I mean, would one Horcrux be much use? Can you only split your soul once? Wouldn't it be better, make you stronger, to have your soul in more pieces, I mean, for instance, isn't seven the most powerfully magical number, wouldn't seven --"

It could be that perhaps 7 is more magical in the dark arts than otherwise, thus we have had no need of hearing about it just yet.

[Alz]

Agreed with SPF on that one - isnt there a further quote than mentions about the power of 7 - or was it JKR ... ummm ...
But yeah - I think 7 was used a la quote above ;)
I guess he was really trying to make sure his life stood the best chance possible :D

[yarvelling]

It strikes me the fact that Harry and Dd are not the only ones after voldy.....

R.A.B...........


What was Dumbledore's brother name? Do we know anyone with the last name of B?

Blaise maybe? maybe not....

nevertheless....it looks like Harry and R.A.B are BOTH (if R.A.B is still alive that is) going to go after the Horcruxes.

Sorry if this has been discussed elsewhere....
Do we know anyone with the name beginning with 'B'? Yes, and as has been mentioned before, there's a possibility that it's Regulus Black. But another that springs to mind who is also in Slytherin house: Millicent Bullstrode.....what do we know of her family? Nothing! Her father or grandfather could be R.A.B..... knowing JKR's fancy for giving certain characters names based on stars or constellations, perhaps:
Romulus, or Rigel.....???

Hopefully we'll find out in a year or two!!

[Alz]

I'm not sure if this is the right place, so I don't mind if it needs moving...

I am wondering about Slughorn and his knowledge of Voldemort's Horcruxes.
We know he altered his memory in the hope that no one would discover that he told Riddle about them, but this means he knows that Riddle actually made the Horcruxes and how many.
So, did he know Dumbledore was struggling to find out how many and what the pieces of soul were put in? Was he only afraid of getting in trouble for telling Riddle about the Horcruxes, or being in trouble for seemingly encouraging him to do it?
And if Slughorn knows about the Horcruxes and how many Riddle would have made, then how many other people know as well?
I will try and get this one back on-track ...
As far as general knowledge - I dont think Horcruxes were that well heard of - most books would only give mention to the name but no details ...
Dumbledore of course is aware of the term and what it does - that is a no brainer ..

Slughorn knew of them - and of course lead Riddle a little further down the path - but for his part he was that distraught at what he had said - what he had done - that he took it upon himself to supress it deep down - almost blot it out of his memory ...

I suppose you could also reflect back to at what point was Riddle made even aware to the point of interest?
Sure - he could have read it in a book - but the details were never there ... ok - answered my own thing there me thinks :o

[Sirius Potter Fan]

What did Sluggy know? and Who else knew? my opinion, is that Sluggy was just so distracted with his socializing and his Slug Club, with making "connections" that he didn't realize probably for ages the significance of Riddle's questions. Sluggy knew Riddle was intelegent, and probably wanted to explore unknown areas in magic. Sluggy was hesitant to answer the questions, because he knew Dumbledore forbade them, but answered them only to stay in Riddle's good graces. I think it likely that Sluggy didn't put 2 & 2 together till Voldemort came back at the end of GoF, and had likely up to that point forgetten all about it ever having happened. Then once 2+2 came out to 4, he certainly wouldn't have told anyone that he was the one that gave Voldemort the key to immortality, and as we know even when Dumbledore wanted information Sluggy tried to change it.

I think dumbledore may have suspected a Horcrux had been used, even in the first book after Harry told him of what happened with Quirrel/Voldemort, and was sure of it at the end of CoS when the Diary was discovered and destroyed.

I don't think Voldemort ever gave the information to any of the DE's, because I think he knew that loyalty due to fear is not true loyalty, and that in entrusting that information to any of them was the same as putting his life in their hands. So how did R.A.B. know? I can only guess. I suspect that RAB followed Voldemort somehow when he was creating/hiding them s

So my answer in a nut shell. . . Sluggy didn't want to know and tried not to know, and didn't want anyone to know he knew. No one else was ever "told" but only a very few made sense of the clues available.

[Alz]

Your forgetting the famous line in GoF "they, who knew the steps I took long ago to ensure I was always around.." and then he talked about how far he had gone down the path of immortality ...

Slughorn was all about popularity - I think he took the chance to answer the Horcruxes query as a chance to show off - he was hesitant to start with - but then launched right into it ...
I think he was worried about his own life are Voldemort ressurected because it is very clear that he would become a target to Voldemort because he would ahve been sure that Riddle had employed Horcruxes in his pursuit of immortal life ...

[Sirius Potter Fan]

they, who knew the steps I took long ago to ensure I was always around..

OK, thing here is "they who knew" PAST TENSE! I assume by that usage that those who knew are no longer alive as all but three surviving DE's were there in the circle: Snape, Barty, and Karkaroff. And the last two of them are now gone. So this leaves us with Snape, who couldn't know. This is supported because, if Snape had had knowledge directly from Voldemort himself of the Horcruxes, Voldemort would not have believed Snape when he used the excuse that he "believed him dead" during the "between" years.

[Alz]

Umm - I think you should re-read the part ...
I took it to mean he was talking about them as if they werent there - because he was still pissed they didnt try and find him - look out for him ...
He was re-iterating that they should have known and realised that he wouldnt have died - they knew that he took steps - but they all chose to bleed into the background ...

It would be interesting to see how others read that me thinks - it raises some interesting questions!

[Sirius Potter Fan]

Thing is. . . Voldemort/Riddle is a smart guy, very intelegent. now. . . if it were me being a really intelegent evil dude, and if I found a way to imortality that could be destroyed, I wouldn't tell anyone! But then. . . there is the fact that he did so love to brag. . .perhaps. . . splitting your soul splits your IQ as well? :p OK say he indeed was stupid enought to spill his life saving work to other evil dudes/dudettes, who would it be? the Lestrange's and Barty went to the Longbottoms looking for info on his whereabouts. Pettigrew went looking for him after his cover was blown, so did they "know"? Only, if they did, why did Pettigrew wait so long? And why did Barty and the Lestranges need to know where to find him? Wouldn't Voldemort tell them where to find him, a pre-arranged meeting place just incase? I mean if you are going to tell someone that you have taken steps to immortality, let them know where to find you if it happens so you don't have to wait years and years for wormtail to save you!

[kashlie]

i don't think Voldemort would have told anybody. he is too pigheaded, and sure of himself to even bother. i mean, he would not have expected to be destroyed at the hands of a baby, nor did he think he could be defeated by anyone else.
i think the steps he took for immortality were purely so he could reign for ever, and not have to pass his 'crown' to another.
He used seven as a sort of goodluck charm, because perhaps he is a little superstitious.

I think he asked Slughorn about Horcruxes for the same reason Harry, Ron and Hermione went to Lockhart for the restricted book for polyjuice potion - easy to sway with the right bribes and comments.

I am not sure when Slughorn altered his memory still. Was it when Voldemort first appeared with Quirrell, or when Riddle's diary was destroyed and DD realised there were Horcruxes about?
How would he have known that Dumbledore would come looking for him? Was Slughorn so absorbed in his Slug Club and what it got for him, that DD knew he'd do anything to keep his prized students?
Did Dumbledore only suspect Slughorn because of the Slug Club? Or would he have questioned all the teachers from Riddle's school days?
I mean, the DADA teacher at the time would possibly still be alive, as it wasn't a cursed position yet, so wouldn't they be the more appropriate person to question?

[Alz]

What is the point of creating mechanisms for re-birth if the only time you need them is when you are killed ... and you forgot the vital step of actually letting anyone know that - on the off-chance you did die - they could come resurrect you.
I mean think people!
Geez - it makes no sense to create Horcrux if you don't let at least one person know that in the event of your demise - you could be bought back.
Now - Voldemort might not have directly told them where each one was - but he would have told at least one person - someone he could trust to resurrect him.
The person he told - we are yet to be given ... remember this - the Lestranges were sent to the Longbottoms because it was believed they knew where Voldemort was - I think a little mis-communication came at this point - everyone seemed to know that Voldemort was dead - I think Lestranges was going to the Longbottoms because they knew where one of the Horcrux was - and I have a darn thread on this ...

Read GoF - read the part where he is addressing the DE's in the circle - he said it himself! :rolleyes: :D

I mean come on - geez - how the heck was he ever going to use the devices if he was dead and the need to use them only came at that point :rolleyes:

[Fortescue]

What is the point of creating mechanisms for re-birth if the only time you need them is when you are killed ... and you forgot the vital step of actually letting anyone know that - on the off-chance you did die - they could come resurrect you.
I mean think people!
Geez - it makes no sense to create Horcrux if you don't let at least one person know that in the event of your demise - you could be bought back.
Now - Voldemort might not have directly told them where each one was - but he would have told at least one person - someone he could trust to resurrect him.
The person he told - we are yet to be given ... remember this - the Lestranges were sent to the Longbottoms because it was believed they knew where Voldemort was - I think a little mis-communication came at this point - everyone seemed to know that Voldemort was dead - I think Lestranges was going to the Longbottoms because they knew where one of the Horcrux was - and I have a darn thread on this ...

Read GoF - read the part where he is addressing the DE's in the circle - he said it himself! :rolleyes: :D

I mean come on - geez - how the heck was he ever going to use the devices if he was dead and the need to use them only came at that point :rolleyes:

I guess my question would be, why would Voldemort think that anyone would come to help him? After he attacked Harry, the only Death Eaters who seemed concerned with his whereabouts was Bellatrix and company. Even Lucius Malfoy made no attempt to find his master. I think since his experience with his first brush with death he realizes that if it were to happen again he'd again be on his own. There has to be another way that Voldemort can bring the Horcurxes into play without the help of others, as we know Voldemort does not trust anyone completely.

[Alz]

Arggghhh - if Voldemort could ressurect himself from the Horcruxes he created - then why the heck didnt he ...
I mean - it wasnt like he had his encounter with Harry then proceeded to go get better again - he was bodyless and helpless!
He required Wormtail & Nagini (Clue there ;) ) to get him somewhere near able to fully re-birth ... once again I urge you to re-cap GoF ... once again he goes over this ...

Logically - just think about it - what is the point of Horcruxes if you cant recover yourself and you dont want to tell anyone about it ... as much use as a chocolate fireguard :rolleyes:

[Fortescue]

Arggghhh - if Voldemort could ressurect himself from the Horcruxes he created - then why the heck didnt he ...
I mean - it wasnt like he had his encounter with Harry then proceeded to go get better again - he was bodyless and helpless!
He required Wormtail & Nagini (Clue there ;) ) to get him somewhere near able to fully re-birth ... once again I urge you to re-cap GoF ... once again he goes over this ...

Logically - just think about it - what is the point of Horcruxes if you cant recover yourself and you dont want to tell anyone about it ... as much use as a chocolate fireguard :rolleyes:

But in the case of his attack on Harry, he didn't have a body, if the spirit or whatever he had left after the attack was not his soul he would have died completely, unless there were other experiments he did that allowed him to somehow exist without his soul. I don't think that's really possible as I believe your soul and spirit as used in this instance are the same thing. That was what saved him from death. Just because he has a Horcrux with a bit of his soul in it, that would still not give him his body back. He needed Wormtail and Harry for that. If you think about it, if what he had left was not still his soul or a spare bit he had at the moment of the attack, that would mean he had no soul and no body: in other words, he would have been dead. If Nagini was a Horcrux and he used her venom to revitalize his soul before he got his body back then that means he has used one bit of the seven bits of soul he had, and thus Harry only need find three more instead of four. Since his soul was already split so finely, I doubt he could use only a part of one of his stored soul bits and still exist. He would have had to use an entire Horcrux and that would then mean only three remain. :rolleyes:

In SS/PS we saw Quirrell use unicorn blood to try and get Voldemort's body back, but all he got was a face :rolleyes: - in that instance he would have revitalized himself - he might even have gotten a new complete body had Quirrell continued to drink the blood for him. If Voldemort needed a Horcrux to gain all of his strength back he would have made Quirrell take him directly to one before he drank the unicorn blood, thus making him complete, but to our knowledge he didn't do that either.

If he was a body without a soul he'd have been a babbling useless idiot like Crouch was after the Dementor sucked out his soul. But Voldemort wasn't that way - he could think and plan he just couldn't do anything for himself because he had no body and couldn't hold a wand. So, it makes sense that whatever he was when he was but a mist - he must have still had his soul or else he would have had no sense of who he was and could not have planned his resurrection regardless of who might have known about his Horcruxes or who might have come along to help him get his body back.

[kashlie]

Isn't it obvious? Staring us in the face? There are only two know people who have found the Horcruxes - Dumbledore and RAB.
What if RAB was Voldemort's most trusted, enough to be told of the Horcruxes? He/she would have been extremely skilled at legilimens and occlumency to fool Voldemort, but we know it can be done.
As soon as RAB found out about the Horcruxes he/she took their chances and found one - this is around the same time as the prophecy was told to Voldemort, because RAB figured if he destroyed the Horcrux, then Voldemort's chances of being defeated were greater...
I guess it is possible though, not trusting anyone THAT much, Voldemort only told RAB of the one. Maybe, just maybe, he told seven DE of one each, and Voldemort, being the secret keeper of their locations, knew they could not tell anyone else - even after the mishap with the AK, because he wasn't dead...





how does that sound?

[Alz]

I'm not sure if this is the right place, so I don't mind if it needs moving...

I am wondering about Slughorn and his knowledge of Voldemort's Horcruxes.
We know he altered his memory in the hope that no one would discover that he told Riddle about them, but this means he knows that Riddle actually made the Horcruxes and how many.
So, did he know Dumbledore was struggling to find out how many and what the pieces of soul were put in? Was he only afraid of getting in trouble for telling Riddle about the Horcruxes, or being in trouble for seemingly encouraging him to do it?
And if Slughorn knows about the Horcruxes and how many Riddle would have made, then how many other people know as well?
I'm gonna go back to the original thread starter before I end up pulling what little of my hair remains :rolleyes:

Another though occured to me about Slughorn wanting to keep moving around since Voldemort came back - someone mentioned this .. you know the fact that Slughorn gave Voldemort the knowledge that perhaps Voldemort feels he should be removed so he cant tell anyone else ...
But could that be all there is to that - or perhaps the Knowledge Of Horcruxes goes a little further?

[kashlie]

Um, sorry Blaise, to go off track again, but um...he created his first Horcrux when he was 16 years old - the diary. Did Slughorn help him more than we realise? Did he give Harry the entire memory?

He had to have made that diary AFTER speaking with Slughorn. How on earth did he learn how to before his final year????
He created the diary, after his chat with Sluggy, then killed his father to make it a horcrux...

[Alz]

Yah this interested me - wasn't sure to make a thread or what ...
Where did Riddle go to finish off his learning on the Horcruxes spell?
We know he used it pretty soon after Slughorn gave him the low-down - but it was never stated exactly how the charm was done - any incantation etc etc ...
How or where did Riddle find this information?

[Fortescue]

Um, sorry Blaise, to go off track again, but um...he created his first Horcrux when he was 16 years old - the diary. Did Slughorn help him more than we realise? Did he give Harry the entire memory?

He had to have made that diary AFTER speaking with Slughorn. How on earth did he learn how to before his final year????
He created the diary, after his chat with Sluggy, then killed his father to make it a horcrux...

When Riddle asked Slughorn about Horcruxes in the memory he had already killed his father. If you remember back to Harry's view of the discussion, Riddle was already wearing Slytherin's ring he took from Morfin and it was the same night he killed his father and grandparents with Morfin's wand and then placed the false memory in his mind so that Morfin confessed.

We don't know enough about how Voldemort makes a Horcrux after he has committed murder. Does he have to make the Horcrux right away or is it something he can do months or years later with the split bits of his soul?

[ldschick]

No that wouldn't make any sense at all, Forte. How would he have already made horcruxes when he didn't know a lot about them until he asked Slughorn?

[Alz]

No that wouldn't make any sense at all, Forte. How would he have already made horcruxes when he didn't know a lot about them until he asked Slughorn?
It is possible that Riddle found about about a spell called Horcrux when he visited the Chamber of Secrets.
Thus he was armed with a powerful spell and probably wanted to try it.
Thing is he didnt know a great deal about exactly what it was - so he went looking for more details.
He was quite a smart boy and chances are he might have had a small idea what it was to be used for - but still not enought to actually use it.
Personally and IMHO - he didnt use it until he spoke to Slughorn and got the skinny - he had the knowledge of the spell and how to perform it maybe - but not exactly sure what it was to be used for.
He might have even just had the spell - bit like Harry and the HBP spells - he wanted to use it but wasnt sure exactly what it did, speaking to Slughorn gave him the missing piece of the puzzle.

[Fortescue]

It is possible that Riddle found about about a spell called Horcrux when he visited the Chamber of Secrets.
Thus he was armed with a powerful spell and probably wanted to try it.
Thing is he didnt know a great deal about exactly what it was - so he went looking for more details.
He was quite a smart boy and chances are he might have had a small idea what it was to be used for - but still not enought to actually use it.
Personally and IMHO - he didnt use it until he spoke to Slughorn and got the skinny - he had the knowledge of the spell and how to perform it maybe - but not exactly sure what it was to be used for.
He might have even just had the spell - bit like Harry and the HBP spells - he wanted to use it but wasnt sure exactly what it did, speaking to Slughorn gave him the missing piece of the puzzle.

In Slughorn's true memory, he told Tom that their was a special spell needed to make a Horcrux, but he would not tell Tom what it was even if he knew it, so that point Tom had to figure out on his own.

If Tom knew the spell in advance, that would mean he had access to a book or some other form of information and I doubt he would have had to coax any informtion from Slughorn. The only thing he seemed to learn from him was that he could split his soul more then once and I got the feeling he already knew that!

[Alz]

I was actually thinking more like in HBP where Tom came across a spell and maybe a description - but no real information on what it did.
As such he had the premise but was looking for confirmation or at least more information on what exactly a Horcrux was.
It just seems that Tom knew a little more about Horcruxes by the time he spoke to Slughorn and thus was getting the final bits of information on exactly what he had discovered.