The fact–value distinction is a fundamental epistemological distinction described between:
- Statements of fact (positive or descriptive statements), which are based upon reason and observation, and examined via the empirical method.
- Statements of value (normative or prescriptive statements), such as good and bad, beauty and ugliness, encompass ethics and aesthetics, and are studied via axiology.
This barrier between fact and value, as construed in epistemology, implies it is impossible to derive ethical claims from factual arguments, or to defend the former using the latter.