From what we see of canon, it does look like while he might have bought into pureblood ideology back in his student/teenage days, he's dropped them by Harry's time. At a guess, it's a combination of his massive bitterness and a much more cynical view of the Death Eaters, Voldemort, and their ideology.

I doubt book-era really believes in much of anything one way or the other, he's far too bitter, jaded, and burnt out. The only thing he has left is the hope of one day getting some sort of payback against those who he feels have wronged him, tempered by the knowledge that even if he somehow pulled it off it wouldn't make a difference or mean anything.

 

There are voices of reason in the Wizengamot(Amelia Bones and probably others). However, I believe that Dumbledore would not have let the news escape Hogwarts in the first place.
What I am trying to get across is that he never tried to atone for his mistakes committed under the guise of ideology. It was Lily Potter he tried to make amends to. So, I am guessing he does not repent anything except for when he unwittingly put Lily in danger.

I agree that this is the most likely explanation. He seemed to care more about vengeance than anything else.

In the memories Snape gave to Harry just before he died, we see the nature of relationship between Dumbledore and Snape. Dumbledore seemed to treat Snape as a victim, eerily like Harry. They also had a conversation in which it seems as though Dumbledore and Snape seemed to understand each other. I guess they both understood that Snape was too broken to hold strictly to an ideology.

Snape is said to be an orphan. Then, who was he living with when he met Lily in the muggle world?

 

He is not said to be an orphan as far as I know, his mum takes him to platform Nine and Three Quarters

 

I think it comes in the DH, just before he confronts Tom in the Forbidden Forest. He muses on Hogwarts being a home for himself, Snape and Tom, all of them being orphans. Please check this anyway, I've read too much fan fiction...

 

It wasn't a home for him because he was an orphan, but because his family life was pretty bad. See the Prince's Tale chapter in DH for details.

 

Closest I found at that time was that:

I also checked the Prince's Tale chapter, and his mother was at King's Cross on their first year, which I didn't remember. I had it in my head that she had died and he grew up with only his father, but I have no idea where it came from. Even the wiki says nothing about her death, so it was probably a fic.

Also, concerning his opinion on blood status, when he was a child and Lily asked him if her being a muggleborn made a difference, he is noted to be hesitating before saying no. And his opinion of muggles was clearly negative at that time.

 

Aahh... Thanks for correcting me.

 

Snape is too committed to the business of saving lives for him to be doing this solely for vengeance. In his own words:

Snape's moral compass is still fucked up -- but he clearly wants to save every life he possibly can. It is part of his self imposed penance, to make up to his memory of Lily. It is his tragedy that he has to kill his mentor/confessor, that he has to calmly watch his pleading colleague (among others) be killed in front of him, that he has to send the boy he spent a huge chunk of his life grudgingly protecting to a futile death (which, by extension, makes much of Snape's redemption futile in his mind.) First war Snape probably wouldn't have cared, but second war Snape does.

 

I feel the only one Snape clearly wanted to save was Lily's son.

You make a good point though, I was always confused with that conversation, sounded more like Harry speaking to Dumbledore than Snape.

Also, it is not made clear if he would even want to save those lives.

 

I believe in the end Snape saved himself. Yes, he was never a nice person, but he did learn from his mistakes and tried to atone for them. So could have Lily saved Severus? Saving as in making him go through these changes earlier? I think so, and probably she wouldn't even need to be in a relationship with him for that. I'm not sure if we were ever told Lily tried to reach out to Snape after their falling out.

 

Why would she reach to him? Snape was hanging around with Death Eaters, despite her friendship. Despite her trying to defend him from accusations. He chose his side. To change he needed a drastic wake up call, and that wake up call came, and his reaction to it wasn't enough.

 

Hey, I'm not admonishing Lily here. Just saying what happened. Maybe if she had reached out to him, she might have convinced him, she might not. It's my personal belief she could have, considering Snape did see the error of his ways on his own later. It took a lot for it to happen, but might have taken less with other circumstances.

 

The problem with that is that she had no obligation to do so. Being a good friend goes both ways. And not supporting a murderous psychopath that wants you and others like you killed is a good-friend move that is generally expected to be made.

 

I don't think her obligation to save him is what's being discussed here.

 

What would her reaching to him do? They weren't separated before the incident. If we believe what Lily says (and we don't really have a reason not to), she tried to be good friend, and that did nothing and it all accumulated until mudblood incident became the straw that broke the camel's back. If she tried to reach to him after that, he would just be validated in his actions.

 

Heh, I'm not so sure about that. The act of forgiveness (once someone realizes their mistakes) can go a long way. Would she be enabling him if she did not react in the first place? Yes, I believe so. But she did react, and Snape suffered and regretted his action for that. Snape (as far as we know) never asked her for forgiveness, but if he was sorry I don't see why she shouldn't have offered it (except for the fact she might not know he was, which was probably what happened anyway).

 

To me it all seemed a bunch of teenage drama. Instead of going into drugs or something similar, Snape just had the bad luck to have been caught by a group of Nazis. I remember Lucius Malfoy welcoming him into Slytherin after sorting. And given that JKR does seem to have built Slytherin up as a fertile ground for Death Eater recruitment, it's quite obvious to me that Snape would have gravitated towards that ideology. There probably was no other in that house. In addition, we know that he grew up with his mother, who was abused by his father, iirc. And that would have engendered in him a resentment for the father (at the very least), and was subsequently fanned into including all muggles and muggleborns.

Lily and Snape's relationship seemed to have started from a childish crush Snape had for her from the very beginning of their friendship. It wasn't able to stop Snape from bowing to peer pressure, and it didn't stop him from becoming a Death Eater. I believe that had Lily forgiven Snape, he, at most, might not have become a Death Eater, but he would have definitely been a sympathiser. I would bet that he would have become something similar to a snatcher. Opportunistic, but clearly still trying to keep up pretenses.

Snape's redemption is predicated on the horror of having betrayed Lily. After losing her friendship, he probably realised that its loss was his fault and tried to distance himself from her. He threw himself into everything else he did. He became a Death Eater and fully ingratiated himself into their circle. But the realisation that his actions would hurt Lily, of all people, who was once his best friend and whose friendship was lost because of no fault of her own, probably spurred his terror. If I remember the scene where he agrees to become a spy for Dumbledore, he does it resignedly. He doesn't want to. He probably wished to tell Dumbledore and leave, but Dumbledore just knew which buttons to push. Snape became a spy because his conscience, which had been beaten down all this while, chose to throw off its shackles when it realised that Lily was a line it would not allow being crossed. The betrayal was a foundation of all that he had become. His entire self was predicated on it. To commit something else so unimaginably horrifying on the same person shocked his guilt into overflowing.

After saying all this, do I believe that Snape would have changed had Lily forgiven him? No. There were too many other factors in play. The fact that Snape had already bowed to peer pressure, that he was a nerd probably trying to impress the cool kids, that he hated the marauders whose ideals were exactly opposite to his own, that his entire house was steeped in an ideology he as a fifteen year old was not mature enough to throw off, the list could go on. An act of forgiveness by Lily would probably have led to a resumption of the status quo. Snape being one person in front of Lily, and another in front of everyone else. Lily would have to keep making excuses for him, and if I were to take it a stretch further, once she would fall in love with James Potter, Snape would take that as a betrayal of their friendship and probably sever ties himself. And then he would truly become a full-fledged Death Eater beyond redemption.

 

I suspect that Lily might have been hoping that calling Snape out on his slide into Death Eater-ism and breaking off their friendship would've been the wakeup call he needed to change his ways. I think she might have been willing to forgive him if he actually made an effort to change his ways and cut ties with all the proto-Death Eaters while abandoning the pureblood philosophy. It seemed like she was at least trying to give him an opening to do that in their last conversation, but he didn't.

And really, after he publicly screamed racial slurs at her, I don't think it's unreasonable for her to say that he needs to make a real effort to show he's changed his ways first.

Actually, that reminds me of a bit of one of the things that always bugged me in canon; exactly how bad "Mudblood" is supposed to be seems to get treated a bit inconsistently. At times it gets treated like it's every bit as bad as the nastiest racial slurs out there, and yet Draco and the like never seem the least bit hesitant about saying it to other students right in front of the teachers. Which ... maybe it's different in British private schools, but using a racial slur in front of a teacher in any school I went to would be get a student in a lot of trouble. Admittedly in Draco's case some of the usual school discipline measures might not work since his parents would obviously approve of what he's doing, but it seems odd that there were never any consequences.