And by ‘tricked’ I mean that they talked to me long enough for me to start writing essays. This is what happens when somebody exchanges more than two comments with me. I probably shouldn’t tell you that. Now everybody will know how to get me to start metaing at them. (I don’t know why you’d want that, but people seem to.)
Jim doesn’t get a lot of screen time, really, and what little he has presents us with a set of seemingly contradictory personality facets. It’s a shallow reading to simply label him ‘unbalanced’ and basically slap him with manic-depression, but it certainly is one possibility. And a lot of people go in for that kind of bad guy. It’s high-drama and certainly lives up to the ‘changeable’ moniker.
But of course, a deeper, and I think both more meaningful and more satisfactory, reading is that like Sherlock, Jim is the master of his own persona. Sherlock built himself as he wished to taken by the world: a mysterious, dramatic, aloof half-noir detective/half-piratical figure. He and John even allude to this at the end of Empty Hearse, when they talk about “being Sherlock Holmes.” They both know that, while that is certainly a part of who Sherlock is, it’s also the part of himself he has chosen to wear. (Which incidentally means there’s a side of him John knows that even we the viewers have barely seen. We don’t know what Sherlock really looks like when he’s not being Sherlock. His entire life is a performance art. But John knows.)
And Jim, whose personality runs in parallel to Sherlock’s so perfectly that even Sherlock has appointed him as his honorary dark side, can be reasonably assumed to have built himself in the same way. He’s keenly aware, after all, of ‘Moriarty’ as a brand. He has a demonstrated mastery of showmanship; that stunt with the three magnificent break-ins at the same time was nothing short of the decade’s greatest publicity stunt, and his behavior at the pool was likewise calculated to leave an impression. About the only time we can even potentially believe that Jim is just being himself is on the roof at St. Bart’s…and even then, he and Sherlock are both acting for their lives, putting on a show and trying to play each other.
So to really try to characterize Moriarty well, I think there’s no choice but to start by looking at his accomplishments: how he built himself as a brand, how he has historically worked when Sherlock wasn’t in the picture, what he has accomplished and why. And then you develop a picture of someone who belongs in the ranks of the great charismatic CEOs: your Steve Jobs, your Howard Hughes, your Coco Chanel, the brilliant, larger-than-life business people whose success came by imprinting themselves on a world hungry for something greater than themselves.
And once you have that down, then you can ask yourself questions about whether he’s mentally ill and how that might map onto the rest of him as a person.
All of which is to say, we know more about him than it seems like we do at first glance, although there is still a lot of room to maneuver. (But then, there’s still so much we don’t know about any of them.)