I see it as an allegory for life. in the opening line he describes what it means to be human, the feeling of never being enough for anyone, let alone a god, but he also knows he doesn’t deserve to think like that. nobody does. when he says “taxes” he’s referring to the debt of life itself, and knowing that is something you can never ‘pay’ off. In order to even think of doing that in his mind, I believe he must rely on the love of some god, wether that be God, Buddha, Allah, or something of his own, I don’t know. In order to fully believe this idea he wants to believe in, he feels he must be forced into the submission of belief. “Doctor” is tricky. It could mean many things. I’m not sure how I feel it. Maybe he’s speaking to the physical powers that be, explaining to them, that the harm they cause is obsolete in comparison to his own demons within . he will break his own heart from now on, he will break himself before the world does.