I think the reason Sherlock wanted to be a pirate is because he wanted to have adventures; he’s a romantic. This is a bit of what deducingbbcsherlock wrote about that line:
JOHN: He’s not like that. He doesn’t feel things that way … I don’t think.
Ha, there it is. I don’t think. John’s sussing Mycroft out a little bit too. Does Sherlock feel things that way? Is that possible?
MYCROFT: My brother has the brain of a scientist or a
philosopher, yet he elects to be a detective. What might we deduce about
Once again, Mycroft flips this as a question back to John. Well, his mind is logical, but look at what he’s chosen to do with his life. What do you think that means? He studies John intently, waiting for his answer.
JOHN: I don’t know.
MYCROFT: Neither do I … but initially he wanted to be a pirate.
In my opinion, the reason this scene seems confusing is that we’re used to Mycroft asking questions he already knows the answer to. Particularly
with John, we often see him guiding the conversation in an almost
condescending way. So when I first saw this scene (and honestly, many
times after), I kept trying to figure out what Mycroft was trying to get
John to realize.
But Mycroft made all kinds of misjudgments in this episode. He’s pretty sure he’s worked out what was really going
on with Sherlock over the last 6+ months. (Lovesick? Yep. Over Irene?
Sherlock thinks logically, yes, but instead of being a chemist, like he went to school for, he’s a detective. He spends all his time helping people, saving people, and dashing about dramatically while he does it. He wants to be the hero:
SHERLOCK: A dragon slayer. Is that what you think of me?
MYCROFT: No. It’s what you think of yourself. (x)
Sherlock has tried very hard to lock down all emotions and romantic notions that he has, to just be logical. But initially, before he started to do that, Sherlock in his truest, purest form, wanted to be a pirate. He wanted to have adventures and be impressive and swash-buckle and fight bad guys and run around a lot.
So I think Mycroft looks unhappy when he remembers that because that reminds him how much colder Sherlock has tried to become, and his own hand in that.
Mycroft basically says:
Brain + Heart = Self
Sherlock’s Brain = Scientist/Logic
Sherlock’s Self = Detective, part logic, part helping people
So: Logic + Sherlock’s Heart = part logic, part helping people
What’s in Sherlock’s heart?
Well, to make that equation balance, what’s in Sherlock’s heart has to do with helping people, sentiment, romantic ideals, etc.
Anyway, I think The Other One is referred to as Redbeard for the same reason the dog would’ve been named Redbeard - Sherlock played pirates. I think The Other One played pirates with him and Redbeard was The Other one’s pirate name; perhaps they played pirates so much it became a nickname.
I also believe that The Other One’s death was what started both Sherlock and Mycroft into “Sentiment is a chemical defect found on the losing side,” at which point Sherlock would’ve stopped playing pirates because it’s too sentimental, not logical. So thinking about a time when Sherlock wanted to be a pirate is a time before all this happened, when The Other One was still alive and Sherlock was happy to be warm and softhearted and sentimental.
Here’s the Redbeard meta>>