John Finnis on Political Authority and Law as Requirements of Practical Reason

What justifies political authority, and specifically the authority of law? Is there a prima facie moral obligation to obey the law? John Finnis’s answers to these questions draw on the Aristotelian-Thomistic natural law tradition, and challenge both the voluntarist and positivist conceptions of political authority and law that tend to dominate contemporary political philosophy. Finnis challenges the voluntarism of social contract theorists such as John Rawls by offering an account of political authority’s justification that relies not on consent, but on the necessity of such authority for the common good, which practical reason directs us to promote. He likewise challenges legal positivists’ non-normative account of law and their related denial of a general moral obligation to obey the law, arguing that this non-normative account fails, even descriptively, to adequately capture what H.L.A. Hart calls the “internal point of view” and what Joseph Raz calls the “legal point of view” – the perspective of citizens or officials who follow the law because they believe in its validity. Ultimately, the differences between Finnis and his voluntarist and positivist counterparts are rooted in Finnis’s more robust and substantive conception of practical rationality, which enables him to recognize and articulate non-instrumental, moral reasons that justify political authority and generate a prima facie moral obligation to obey the law.