"As a slave one cannot undertake obligations without the consent of one’s master. As a citizen one cannot undertake obligations unless the legal system of the State in which one holds citizenship permits one to do so. Neither a slave nor a citizen is a free person, although those who are held as slaves or citizens may well be free persons: it is just that their freedom is not respected."

“A natural right in the strict sense is that which is naturally under a person’s control, his body with its faculties of movement, feeling, thought, and speech. By extension, a natural right is what a person brings under his control without violating any other person’s natural rights.”

“An anarchist does not want to rule others and does not want others to rule him. Nothing is so despicable as half-an-anarchist.”

“I recall an incident involving the late George Stigler at a conference in Spain in the 1980s. Hearing that I had written a book on reason and natural law, Stigler started to ridicule reason, going so far as to say that there is as much reason in a monkey's antics as in any human act. At that point I asked him whether he was trying to tell me something about how he wrote his books; he gave me a blank stare and stormed out of the room.”

“There are then, at least two dialectical truths. The first is that you and I are reasonable creatures; the second that you and I ought to be reasonable. Because of the second, we can say not merely that we cannot reasonably deny the first, but also that we ought not to deny it. If these dialectical propositions are errors, they are irrefutable errors: there is no way for men qua rational creatures to find out what is wrong with them, just as there is no way for men qua rational creatures to cast doubt on their truth.”