This is a reference to the classic problem, the Prisoner's Dilemma (I shrink at the thought that I am insulting my reader's intelligence here).
I have decided that my morality from now until I change my mind(I don't expect to do so) will be based on adherence to the cooperative portion of the prisoner's dilemma. It's sorta like a game theorist's answer to the golden rule. Let me explain.
Let's face it: The payoff from stealing things is high, and the chance of getting caught is low. As an economics student I can't ignore the expected value of occasional thievery as positive for the thief.
However, if I steal from anyone, I am made marginally better off, but they are likely made proportionately worse off. Moreover, if everyone steals from everyone, we will all spend all our time worrying about protecting our things and not have time to live our lives. This is unacceptable.
If I decide not to steal from anyone, they may still steal from me, but there is also the possibility of punishment for them, and more importantly, I wish to demonstrate my intention to enter into a stable equilibrium of "no one steals" and I can broadcast this by sticking to my principles in spite of being a victim of theft.
Let me say that I was not a thief before I wrote this, this is merely a way for me to logically justify continuing my (arguably economically irrational) behavior.
Let me also say that I refuse to appeal to a higher authority who refuses to show up for court (or indeed, at all) to justify moral behavior. I'm still an atheist. This system allows for atheist morality.