Every Choice Function is Pro-Con Rationalizable

We present a new choice model. An agent is endowed with two sets of orderings: pro-orderings and con-orderings. For each choice set, if an alternative is the top-ranked by a pro-ordering (con-ordering), then this is a pro (con) for choosing that alternative. The alternative with more pros than cons is chosen from each choice set. Each ordering may have a weight reflecting its salience. In this case, each alternative is chosen with a probability proportional to the total weight of its pros and cons. We show that every nuance of the rich human choice behavior can be captured via this structured model. Our technique requires an extension of Ford-Fulkerson Theorem,which maybe independent interest. As an application of our results, we show that every choice rule is plurality-rationalizable