1. Normative Versions of Legal Positivism H. L. A. Hart (Oxford) H. L. A. Hart (Oxford) Hans Kelsen (Vienna, UCLA) Hans Kelsen (Vienna, UCLA)

2. Problems with Natural Law Theory H. L. A. Hart argues that the command theory cannot distinguish between a legitimate government and an armed robber ("give me your money or else"). The "Gun Man" objection. H. L. A. Hart argues that the command theory cannot distinguish between a legitimate government and an armed robber ("give me your money or else"). The "Gun Man" objection. Parliamentary or constitutional law, laws governing the actions of the sovereign, do not count as law at all. Parliamentary or constitutional law, laws governing the actions of the sovereign, do not count as law at all.

3. Law as a System of Rules Laws constitute a hierarchical system of rules. Laws constitute a hierarchical system of rules. Primary rules are like Austin's commands, Primary rules are like Austin's commands, Secondary rules concern how primary rules are recognized as valid, changed, applied to particular cases, and enforced. Secondary rules concern how primary rules are recognized as valid, changed, applied to particular cases, and enforced.

4. Legal Validity A law is valid or binding if it belongs to a system of laws that is in force in a particular society. A law is valid or binding if it belongs to a system of laws that is in force in a particular society. The validity of a system depends on the validity of its most fundamental secondary rules: The validity of a system depends on the validity of its most fundamental secondary rules: –“Grundnorm” (Kelsen) –Ultimate rules of recognition (Hart)

5. Validity of Grundnorms It is generally followed, and It is generally followed, and most people accept it as valid/binding, i.e., most people accept it as valid/binding, i.e., –they follow it because they believe it is valid, and –they criticize or find fault with those who deviate.

6. The “Internal Perspective” Legal theory involves taking the "internal perspective" of one who accepts a given system as valid. Legal theory involves taking the "internal perspective" of one who accepts a given system as valid. This distinguishes law from sociology, which always takes the "external perspective" of the objective scientist. This distinguishes law from sociology, which always takes the "external perspective" of the objective scientist.

7. Some Philosophical Problems Reduces to Sociology? Reduces to Sociology? Vicious circularity in definition of validity? Vicious circularity in definition of validity? What sort of thing is a rule? What is it to “follow” or “accept” a rule? What sort of thing is a rule? What is it to “follow” or “accept” a rule?

8. Does Law Reduce to Sociology? The validity of a system of laws seems, on their acccount, to be a matter of sociological fact: which system (which Grundnorms) to most people treat as valid? The validity of a system of laws seems, on their acccount, to be a matter of sociological fact: which system (which Grundnorms) to most people treat as valid? This threatens to collapse their distinction between the disciplines of law and sociology. This threatens to collapse their distinction between the disciplines of law and sociology.

9. A Circular Definition? Validity is defined in terms of what most people believe to be valid. Validity is defined in terms of what most people believe to be valid. If we don't already understand what legal validity means, we can't understand their definition. If we don't already understand what legal validity means, we can't understand their definition.

10. What are Rules (Conventions)? It can't be a mere pattern of behavior, since that leaves no room for the possibility of someone deviating from the norm or breaking the rule. It can't be a mere pattern of behavior, since that leaves no room for the possibility of someone deviating from the norm or breaking the rule. It can't be a mere linguistic entity, like a sentence or statement, since these must be interpreted (by a linguistic or semantic rule). It can't be a mere linguistic entity, like a sentence or statement, since these must be interpreted (by a linguistic or semantic rule).