"Are we human, or are we dancer" was taken from a journalist Hunter S. Thompson before he committed suicide, Flowers said this is where he got that line, and the deeper meaning behind that line is this:
In this song, dancer is used as a metaphor for an orchestrated, rehearsed act. Something without individuality. Without emotion i guess, like a hollow act. A dancer has no room for individuality when in groups(like a person in society) they have to follow an exact pattern that everyone else does. If you've ever seen a dancer screw up, it's very noticeable. so when he says are we human or we dancer, he is comparing someone who is human(not as a species, but as a quality, human means emotional and individual; able to think for oneself). Then the word dancer in this song is also used as a quality, not as a noun. Which is why there is no 's' at the end, because he wants to stress that he doesn't mean a bunch of dancers, but rather that he's asking if the world is full of the dancer quality. It's the same reason there is no 's' at the end of human, because he could've said "Are we humans, or are we dancers" but that doesn't bring about his deeper meaning, which is why he is using 'dancer' and 'human' as qualities, or adjectives.
This the explanation of The Killer's song "Human". I LOVE IT. I got this explanation from Yahoo answers from an anonymous poster.
Kudo's anonymous. xoSusan