One of the most important parts of Aquinas’s discussion of human law for our purposes is the account he gives of its relation to natural law in Question 95, Article 2. Think especially about the two ways of deriving human law from natural law that he describes there. It’s also worth looking back at what Aquinas says about change to natural law in Quest. 94, Art. 5. Think what Aquinas might say about the relation of natural law to such things as traffic laws—for example, a law requiring everyone to drive on the right side of the road.

A second key part of Aquinas’s discussion concerns the question what we are to say when an apparent human law is not derived from natural law. Question 9, Article 4 is the heart of Aquinas’s answer. Ask yourself both exactly what Aquinas intends to say and whether he is right. With regard to the former question, do you think he wishes to claim that nothing can count as a human law unless it is derived from natural law (roughly, unless it is just)?

The issue of whether “unjust law” is a contradiction in terms is one about which philosophers of law disagree. Another such issue is the extent to which the law consists of rules. Most of the remaining articles in Question 96 and the whole of Question 97 are related to this issue and others that arise when it is discussed. Even though Aquinas describes law as a “rule and measure of acts,” these passages suggest that he might not be prepared to say simply that law consists of rules and leave it at that. What do you think he would say?