The ultimate rule of recognition is both law and fact.

Evidence

The case for calling the rule of recognition ‘law’ is that the rule providing criteria for the identification of other rules of the system may well be thought a defining feature of a legal system, and so itself worth calling ‘law’; the case for calling it ‘fact’ is that to assert that such a rule exists is indeed to make an external statement of an actual fact concerning the manner in which the rules of an ‘efficacious’ system are identified. — HLA Hart, The Concept of Law (Clarendon Law…, 343

Categorization

• XREF: XREF: Relates to the debate between legal positivism and natural law about ultimate validity. — connects to: Identifying valid legal criteria in any system is an empirical question of fact — HLA Hart, The Concept of Law (Clarendon Law…, 682
• corroborated: 2 independent passages support this claim — HLA Hart, The Concept of Law (Clarendon Law…, 343

Broader Connections

• Identifying valid legal criteria in any system is an empirical question of fact #expands (0.85) — HLA Hart, The Concept of Law (Clarendon Law…, 682