We belong together because we are the same

[azdaema]

I once saw a tumblr post what went something like this: "in my gay incest ships, they’re super different (example: thor x loki) and in my het incest ships they’re super alike (example: cesare x lucrezia)." I wish I could find that post again, and begin this essay with quoting and crediting it, because this is—in effect—an expanded version of that idea.

Within a poetic, literary context, how are incestuous and homoerotic relationships alike?

The obvious answer is that both are traditionally taboo. The majority of the population is disinterested by such things in a visceral, unchangeable way, and thus the rare individual who is interested is seen as deviant, defying nature.

Which is true, but I don't think that's really the heart of it. I think the real poetic resonance is this: We belong together because we are the same. They are alike in a way lovers are not supposed to be, yet this commonality is not merely neutral but actually good, because it means they can understand each other in a way that others don't.

But we still need there to be some space between them.

If there is a verb that comes with love, it's "to have." And if there is a verb that comes with desire, it is "to want." In love, we want to have; we want to know the beloved; we want to minimize the distance; we want to contract that gap. […] In desire, we want an Other, somebody on the other side that we can go visit, […] In desire, we want a bridge to cross. Or in other words, fire needs air. Desire needs space.

Esther Perel, "The secret to desire in a long-term relationship"

If you are to combine the likeness of same sex and the likeness of same family, you need a stark difference to balance it out. Thor/Loki and Elsa/Anna are both popular ships because the siblings are distinctly and pointedly different. They love each other, but they've had a falling out—Elsa was isolated for years; Loki started a war; Dean left and went to college. They need to reconnect. There is polarity and tension between them, which is all very USTy and exciting.

I am not interested in shipping Fred and George Weasley. They're not identical—George is quieter, Fred is more the ringleader—but they are alike enough that there's no synthesis to be had. It's inching up on selfcest. They melt into each other—not in a cool, marbled way, but in a homogeneous, blob way.

Both serve similar narrative roles, and have much in common. In this way, the two tropes' relationship to one another serves as a metaphor for each tropes themselves. And that likeness is a good thing, but if you overdose on it, the effect stops working.