ABYSS

The abyss in question is, as a couple have pointed out, a reference to a famous line by Friedrich Nietzsche that in English goes “Whoever fights monsters should see to it that in the process he does not become a monster. And if you gaze long enough into an abyss, the abyss will gaze back into you.”

As it relates here, Batman is basically telling Owlman that he is similar to himself in that they both once fought monsters. But Owlman allowed himself to become a monster. That when Owlman faced his “abyss,” he was not strong enough to fight it, which Batman finds contemptible. There’s also a bonus layer to it, because Owlman is clearly a nihilist, someone who rejects the meaning of life and morality as meaningless. Nihilism was a philosophy that was originally put forward as a thought experiment by the aforementioned Nietzsche, so in a way Batman is throwing the words of the man who founded Owlman’s philosophy back in Owlman’s face.

It is a metaphor based on a famous writing from Friedrich Nietzsche. The whole theme of the movie is based on him actually. He was very outspoken against nihilism but thanks to people misinterpreting what he was saying, they think he was a big supporter.

Owlman saying nothing matters is nihilism. It is the belief that there is no purpose and everything is meaningless. Nietzsche thought that was very destructive and not a good mindset. In one of his famous writings he makes mention of looking into the abyss and it will stare back. Essentially what he meant was that if you work against something, you risk becoming that thing. So Batman fights criminals and by doing so he is constantly tested on whether or not he will give in and do something like committing murder himself. That’s what he meant to Owlman. Owlman took a look at the flaws of the world and the evil (the abyss) but then he “blinked”. He decided to fight it by becoming it. He would kill everything to stop the evil.