David Hume’s moral philosophy

David Hume sought to build a moral philosophy from a few objectively defensible principles.
It is described in:      http://plato.stanford.edu/entries/hume/
under:
   7. Moral Philosophy
7.1 Moral Rationalism: Critical Phase in the Treatise
7.2 Sentimentalism: Constructive Phase
7.3 Self-Interest Theories: Critical Phase in the Enquiry
7.4 Justice: Constructive Phase