A free economy, based on individual ownership, harnesses individual greed to achieve collective prosperity.
A constitutional republic balances the branches of government and the state/federal division to harness the will to power.
The genius of both is that they depend only on man's nature as it naturally occurs, and do not depend on any religous or moral awakening.
I'd say selfish, rather than evil. And I would regard such selfishness as being no more evil than fire. To be sure, it can--if left nchecked--be grossly destructive and may be used for evil ends. On the other hand, as the primary motive force behind human behavior, it is also an essential requirement for doing good.