An original editorial by Subtle Science
The motivation behind actions matters tremendously: it's the whole basis of morality. If you only choose to do the right action because someone else tells you to, or because you want to live up to his/her ideals, then you have no real sense of right and wrong and no ideals of your own. The negative flip side would be if you didn't do anything bad just because there were laws prohibiting it and punishments--you're not actually a good person; you're allowing, again, outsiders to dictate your behavior, not your own conscience. Morality comes from realizing something is the right thing to do, no matter the cost, on one's own; or realizing something is wrong and electing not to do it--especially when you know you could get away with it, without punishment.
Typing away here on MuggleNet has made me realize that the issue of morality is why I find Snape's character so fascinating. It seems that JK Rowling is building him as a person who is finding his own morality. He fell to the depths of lack of morality: not only surrendering his will and actions to another, but that person's being Voldemort, the epitome of evil. While Dumbledore's opinion now obviously matters greatly to Snape, that's not, apparently, what drove Snape to quit the Death Eaters--he chose the moral reversal himself. In the present day of the books, Dumbledore's high opinion of Snape guides and bolsters him, but it did not become a factor until after Snape left Voldemort's service.
Harry's moral development in the books is very close to Snape's--without the side journey into the Dark side, albeit with a significant poor choice on Harry's part as well. Over and over, Harry is portrayed in the books as having to weigh outside pressures against what he himself knows to be the right course. The only time he chooses wrongly is at the end of The Order of the Phoenix--but it's a harsh, humbling lesson he has to learn: he's not infallible, even though he's made an extraordinary number of right calls (particularly for an 11-, 12-, etc., year-old). Like Snape, Harry must make his own choice regarding right and wrong, and he must accept and learn from his own failing.
Rowling doesn't preach defying authority; however, she does emphasize evaluation and personal responsibility, which may lead one to defy authority. Snape defies Voldemort, having concluded that Voldemort represents immorality. Interestingly, Harry, technically, is defying Dumbledore himself throughout the books. Harry elects to break a variety of school rules established by the Headmaster, but always for valid reasons that required extensive thought and consideration, not done lightly. All ideas must be weighed by an individual who then chooses his own path to moral development.
The idea that Snape may turn out to have been evil all along is distasteful for this reason. If Snape never truly had a moral reversal, if he continues to work for Voldemort, if he betrays Dumbledore either for Voldemort or for his own agenda...what a thoroughly, appallingly immoral character Rowling has created. The whole foundation of the theme of choices and redemption collapses. It really doesn't matter what Harry does or if he continues to develop morally, since the one person in the series who best illustrates the consequences of wrong moral choices and the reward of choosing the more difficult, right path that would lead to ultimate redemption...was a phony from the start, and none of those events and choices actually occurred.
That's a worse ending than having Voldemort win; at least, if Voldemort won, the readers could still have the impression that someone, somewhere out there, would organize and lead another resistance. In that case, the triumph of evil need not be permanent; there could still be moral people in the world, choosing the right, difficult path. If Snape turns, then there really is no possibility of people's truly changing and choosing the right side; self-serving motivation triumphs over both good and evil, and amorality rules. Choices and redemption, therefore, do not exist.
Posted by: Rachael