Many recoil at the idea of sin because they don’t feel comfortable with someone being able to judge the value of the actions of another. This position is based on two ideas that are equal in their obvious falsehood: that all people are equally good, and all behavior is equally effective.
That value hierarchies exist in all human concepts and actions is obvious. Any who claim that one behavior is equally as good as another are lying, and they know it. Their every action is based on ranking judgment between options available.
It is no major leap to infer that the goodness of one’s ranking can be assessed by objective, rational inquiry. This, too, is an activity engaged in by every human every day, and those who claim it is not possible or appropriate are liars on the grandest scale.
The ability of honest investigation extends beyond personal experience and applies both to the goodness of the outcome sought and the efficacy of the path to obtain it, both of which are choices among many options.
It is abundantly clear that it is possible to accurately judge behavior, but this does not imply that it is easy.