Discourse on Ethics

There are two ways for approaching the question of truth: first, by adopting an approach that is wholly objective and second, by adopting a partly subjective approach. As far as the former is concerned, we are quite familiar with the physical sciences-that is, the question "From whence does something originate or of what does it consist?" As far as the latter is concerned, the question becomes "How do we appraise something according to a certain set of standards, norms, or rules?"
Aesthetics deals with the objects, in this case perceptual or audible, that we call beautiful or ugly. Logic deals with the objects, in this case statements or arguments, that we call true or false. And ethics deals with the objects, in this case the conduct of men, that we call good or bad. What distinguishes the normative from the descriptive also concerns the validity or propriety with which we judge, instead of merely stating it, that such and such is the case. An anthropologist is someone who may record the different mores and customs that exist in different societies, but it is not the job of an anthropologist to say whether they are good or bad or to identify which ones are better and which are worse. The same goes for a botanist who classifies various plants or a psychologist who classifies various mental states.