From a very early, as-of-yet uncollected short story “The Planet Trillaphon As It Stands In Relation To The Bad Thing”. He’s writing about depression (i.e. the Bad Thing), but one could almost substitute “sin” for “bad thing.” As we all know, it is easy to cling to human agency and willpower when it comes to less significant problems. But depression (or anger, or addiction for that matter) is not one of them. DFW paints a perfect and frankly rather horrifying picture of man in need of a solution outside of himself:

“Because the Bad Thing [depression] not only attacks you and makes you feel bad and puts you out of commission, it especially attacks and makes you feel bad and puts out of commission precisely those things that are necessary in order for you to fight the Bad Thing, to maybe get better, to stay alive. This is hard to understand but it’s really true. Imagine a really painful disease that, say, attacked your legs and your throat and resulted in a really bad pain and paralysis and all·around agony in these areas. The disease would be bad enough, obviously, but the disease would also be open·ended; you wouldn’t be able to do anything about it. Your legs would be all paralyzed and would hurt like hell … but you wouldn’t be able to run for help for those poor legs, just exactly because your legs would be too sick for you to run anywhere at all. Your throat would burn like crazy and you’d think it was just going to explode … but you wouldn’t be able to call out to any doctors or anyone for help, precisely because your throat would be too sick for you to do so. This is the way the Bad Thing works: it’s especially good at attacking your defense mechanisms. The way to fight against or get away from the Bad Thing is clearly just to think differently, to reason and argue with yourself. Just to change the way you’re perceiving and sensing and processing stuff. But you need your mind to do this, your brain cells with their atoms and your mental powers and all that, your self. And that’s exactly what the Bad Thing has made too sick to work right. That’s exactly what it has made sick. It’s made you sick in just such a way that you can’t get better. And you start thinking about this pretty vicious situation, and you say to yourself, ‘Boy oh boy, how the heck is the Bad Thing able to do this?’ You think about it – really hard, since it’s in your best interests to do so – and then all of a sudden it sort of dawns on you… that the Bad Thing is able to do this to you because you’re the Bad Thing yourself! The Bad Thing is you. Nothing else: no bacteriological infection or having gotten conked on the head with a board or a mallet when you were a little kid, or any other excuse; you are the sickness yourself. It is what ‘defines’ you. You realize all this, here. And that, I guess, is when if you’re all glib you realize that there is no surface to the water, or when you bonk your nose on the jar’s glass and realize you’re trapped, or when you look at the black hole and it’s wearing your face.”