In the anime Haibane Renmei there is something called the circle of sin which is a paradox that some characters are trapped into (the theme of the anime is redemption and going to heaven):

Communicator: "To recognize one's own sin is to have no sin. So, are you a sinner?"
Rakka: "Uh! But if I think I have no sin, then I become a sinner!"
Communicator: "Perhaps this is what it means to be bound by sin. To spin in the same circle, looking for where the sin lies, and at some point losing sight of the way out."

http://www.arcadien.net/node/28

Some are deemed "sinbound" because they are "born" sinful and the more they try to find out where the sin lies the more likely they are to sin when they try to fix things (something like this).

Does this make logical sense? Where does this paradox come from?

One of the characters, Reki, behaved like a "good Haibane" to be saved (metaphor for religious hypocrisy) but this only put her deeper into the circle of sin. She is saved because she decides to trust Rakka to save her. Rakka in her turn had been saved by another person too.

Does this mean that the way out of the paradox is by getting someone else to save you? Why? Where does this idea come from?