Proportionalism is an erroneous moral theory which evaluates a moral decision by the comparison of good and evil effects in a proportional way before the human act is executed. This particular theory of moral relativism holds an act can be morally acceptable when good effects proportionally outweigh the evil effects;  or, the person judges an action as more beneficial than harmful.

The crucial problem with the theory is the prominence of the subjective evaluation of a human act and in doing so minimizes objective element which is the the moral object itself.  According to this theory, the moral object can be evil and due to proportional reasons, the objective can be accepted even if it is evil.  Proportional evaluation strains to explain how an evil can be transformed into a good by the intention of the actor only.  The object of an act is either good or it is evil, but cannot be both.