The next essay in “Battlestar Galactica and Philosophy” is “Gothic Anxiety” … no, really, it’s not an essay from “Batman and Philosophy”, but is from “Battlestar Galactica and Philosophy”. It’s essentially uncredited, and covers off a trope used frequently in, at least, Gothic Horror: the idea of double selves, specifically doubles and dopplegangers.
The relation to the reimagined “Battlestar Galactica” series should be obvious, since it seems to contain both. You have doubles specifically when it comes to the various human Cylon models, and internal dopplegangers play a large role in Gaius Baltar and Caprica Six’s story arcs. The essay does a reasonable examination of those cases, but I think doesn’t really explain why these things are commonly used as horror tropes, per Jekyll and Hyde and variations on that theme.
For doubles, the fear is, I think, fairly obvious. There’s a fear of them taking over your life, as also seen in movies like “Single White Female” … and then killing you off so that they can live it. There are concerns about an evil twin using your face to commit evil and letting you take the blame for it. There’s also the fear of having to fight someone who pretty much has exactly your skills and abilities to stop them from doing evil, to you and to those you love.
There is a bit of this in the doppleganger as well, as there is the fear that you have this personality inside you who is not you, who might be literally trying to take over your life, through taking over your body. But I think that there’s another big fear, which is the fear that the doppleganger isn’t some foreign personality that has infected you and is trying to take over, but is, in fact, really you. A part of you that you don’t like. A part of you that you repress. A part of you that might, in fact, actually be you. Maybe that personality is who you really are, and the person you are now is the facade over top of that. That fear, the fear that you aren’t who you think you are, or that you are in fact capable of the evil that that personality is committing, drives a lot of the horror of that scenario, it seems to me.
As the essay points out, Baltar and Six’s cases are not like that. They are more complementary, providing help and benefit and supplementing their own abilities. They may, in fact, reflect ignored or buried parts of their personalities — assuming, of course, that they aren’t actually angels — but those personalities are benign and helpful. They bring good aspects of their personalities forward, generally, and reveal things that they need to worry about. The competing doppleganger is not of that sort. It either competes with the main personality, or brings forward aspects of their personality that they don’t want to face, live with, or even have. Even if they are what’s necessary, they do what the main personality doesn’t want to do, at a minimum. And that is frightening on a number of levels, from losing control to understanding that that person is who you really are.