Ethics considers the nature of human thought and action. Do good and evil exist?

If they do exist, what do those terms mean and how can we know which actions or thoughts are which?

If they don’t exist, how can ethical theories work without them, and what will prevent people from destroying themselves and the world?

My old site was dedicated to ethics, arguing that moral judgment is relative (not objective) and can best be handled as a descriptive enterprise (observing how people do feel and act) rather than a normative one (deciding how people should feel and act). Of course I do believe that given defined interests (i.e. I want to be just, or honest, or avoid cruelty) then certain actions would be pre/proscribed.

That site contains a a detailed rebuttal of the realist/consequentialist ‘Moral Landscape’ theory advanced by popular author Sam Harris. This was followed by a further rebuttal (published at Scientia Salon) of his attempted ‘clarification’ of the theory.