It is therefore necessary to characterize, in general terms,
those principles, rules, and standards relating to the conduct
of individuals which belong to morality and make conduct
morally obligatory. Two related difficulties confront us here.
The first is that the word 'morality' and all other associated
or nearly synonymous terms like 'ethics', have their own
considerable area of vagueness or 'open texture'. There are
certain forms of principle or rule which some would rank as
moral and which others would not. Secondly, even where
there is agreement on this point and certain rules or principles
are accepted as indisputably belonging to morality, there
may still be great philosophical disagreement as to their status
or relation to the rest of human knowledge and experience.
Are they immutable principles which constitute part of the
fabric of the Universe, not made by man, but awaiting discovery
by the human intellect? Or are they expressions of
changing human attitudes, choices, demands, or feelings?
These are crude formulations of two extremes in moral philosophy.
Between them lie many complicated and subtle variants,
which philosophers have developed in the effort to
elucidate the nature of morality.