Traditional branches are cosmology and ontology.
• Epistemology is concerned with the nature and scope of knowledge, and whether knowledge is possible. Among its central concerns has been the challenge posed by skepticism and the relationships between truth, belief, and justification.
• Ethics, or 'moral philosophy', is concerned with questions of how persons ought to act or if such questions are answerable. The main branches of ethics are meta-ethics, normative ethics, and applied ethics.