Even where it is not beneficial to their own gain, people regularly behave fairly and justly. On the other hand, opportunistic and unfair actions are not the peculiarities of a few "evil" market participants, but rather represent a completely normal alternative course of action that is frequently considered. Since the world of economics consists of both good and evil, a theory is needed that can explain both on a unified, preferably scientific basis and connect them with the results of economic actions. Friedrich Thiessen draws on evolutionary scientific insights and attempts to illuminate and explain good and evil in market economies using concepts that are recognized and widely accepted in economics.