The economic approach to the 'greater good of humanity'

In the last post I suggested that a much more likely approach to the 'greater good of humanity' argument is to take a page from economics, and argue that people will be good as long as the benefits of good behavior outweigh the price of that behavior.

This seems to give rise to a challenge: How would a bad person reach this conclusion?  How could anyone know that you will get more out of society by behaving well? 

This is an important question, and on the surface seems difficult to answer. Instead, let us try to put ourselves inside the mind of a bad person and see how the logic might go. Let us consider the worst sort of bad person, one who is sociopathic and supremely self-interested person, who believes himself superior to everybody and cares not one whit about right and wrong.  Let us pretend that this person truly has no compunction about violating even the most basic social norms if it is in his benefit, but is also smart enough to be able to think in advance about his actions and their results.

He would observe that his crimes, if discovered, would not benefit him in the long run. Even if the threat of revenge or jail were removed, if people were aware of the threat he represented, they would avoid him, thus making it harder to achieve the pleasures or benefits that he seeks. The more the person was known to steal, the more people would hide their valuables when they saw him. The more he was known to kill, the more people would flee when he came near.  Thus, if his deeds were known, it would become increasingly difficult to continue to benefit himself at their expense, and he would face ever increasing risk of reprisal. 

Thus, purely out of self interest, the person would realize that it is easier to appear to be behaving well, to maintain easy access to the pleasures and benefits of society than to work ever harder at benefiting from badness. Thus, such a person would behave in a way that appears fully honest for their own nefarious ends, even becoming a trusted friend of the intended victims. 

However cruel the intention, the as the sociopath groomed this facade he would observe a remarkable fact. The more genuine and honest he appeared, the easier it was for him to get social benefits and pleasures. The more honest the person appeared, the less stealing would be required, as people would be more willing to lend him money; the less murder would be required as his enemies would find themselves punished by more of his friends and admirers;  the less rape would be required as more people began to actually pursue his affections. 

In short, In short, violation of social norms has an increasing marginal cost and decreasing marginal utility,  and following social norms would have a fixed or decreasing marginal cost but increasing marginal utility.  As long as the marginal utility increases, any rational self-interested being would seek to remain on the "good side" of the social norms most of the time. 

Thus even the most cruel person may be transformed into one who behaves in a good and honest way, as long as the benefits of participation in human society outweigh the costs of good behavior.