I don't think that this is possible within the frame of the series and the fans do not want see that. I can imagine him getting violent to protect John. But he will not turn into a villian.
However, there is a pastiche in which Holmes turns out to be Jack the Ripper. I stopped reading somewhere in the middle. Too terrible an idea for me and totally out of character. 

I think in the books there is no indication either that he might become a villain. The parallels between him and Moriarty are much stronger in the the series than in the books. But the difference is, as Moriarty puts it, that Sherlock is on the side of the angels (even if he is not one of them). Even if he does not do sentiment he keeps saving lives again and again. 

Sherlock could become evil,  then we could have more sexy villians! 

It's a good question becuase it gets at the heart of the story.  

There is a lot of wonderful tension in Sherlock's character exactly becuase he could be a villain.  He's smart enough and resourceful enough.  And he is rejected by many "normal" people.  Look at the way Sally and Anderson treat him.  Why should he care about people? Sherlock's own brother tells him that "Caring is not an advantage." 

But Sherlock has a heart.  And Sherlock's heart has John in it, and Molly, and Mrs. Hudson, and maybe even a little room for Lestrade.  Sherlock is a great man and might even be a good one, somebody once said  ;-)

But the tension between what Sherlock could do and what he does do is part of what makes him so fascinating.    

sj4iy wrote:

In this series, they did a very good job of contrasting Sherlock to Moriarty.  Sherlock actually thinks he could be Moriarty, and that it's simply his choice to not be like him.  However, over the course of the 6 episodes, he finds out more and more about himself until he realizes that he could NEVER be like Moriarty.  His character arc is very definite about this.  Sherlock cares about others, especially John and Mrs. Hudson, while Moriarty only sees ordinary people as pawns in his games.

So no, I don't think that he could ever become evil, even with reason.

Oh, that was so beautifully put, I couldn't agree more with your analysis about Sherlock. 


 

Interesting topic and well put in the posts. Personally I've often wondered about Mycroft's line to John concerning Sherlock's career choice.  He could have been a scientist or philosopher but chose to be a detective.  "What might we deduce about his heart?"  Yes, good question.  If someone becomes a detective, what does that tell us about their heart?

The writers provoke the idea of Sherlock being tempted to step across the line into the darkness although I think Sherlock (like Holmes in canon) plays by his own rules and likes to decide about right and wrong himself. In canon Holmes is prepared to give his own life in case he at the same time could kill Moriarty. And in retrospect looking at TRF the fallout is telling: Moriarty is dead and Sherlock is alive. And if it is the only possible solution and the rules are wrong (meaning you can't legally convict Moriarty because of his Brook personality) the victim has to do it.

We have got the encounter with Mycroft in Scandal when the brothers talk to each other on the phone and in the morgue about law.

1. Sherlock on the phone on Christmas. Mycroft: “We’re not going to have Christmas phone calls now, are we? Have they passed a new law?” The implication is that Sherlock never does social calls on Christmas. Mycroft’s subtext is probably: You would only call me on Christmas if there were a law that said: Don’t call your sibling on Christmas. If it were not allowed Sherlock would do it. He is the one to break the rule when he wants to. He is unconventional and no-one for social niceties.

2. Mycroft offers a cigarette and Sherlock asks: Isn’t there one of these law things? And Mycroft mockingly answers: We’re in a morgue. There's only so much damage you can do. Sherlock plays the ball back as if the phone call conversation goes on about law. Why do you offer a cigarette when you always play by the rules. You are so conventional and boring. The subtext there is from Mycroft: Even you can’t destroy anything here in a morgue with your tendency to break every rule available and bring disaster upon something.