In this chapter, I discuss Robert Alexy's dual-nature theory of law conceived as a version of legal constitutivism. Alexy argues (i) that legal acts necessarily raise a claim to correctness; (ii) that it follows from law's raising a claim to correctness that law has a dual nature; (iii) that the dual nature of law implies that legal acts that do not raise a claim to correctness, or raise one but fail to satisfy it, will lack legal character or else will be legally defective; (iv) that the dual nature of law is incompatible with the separation thesis of legal positivism; and (v) that it follows from law's dual nature that legal argumentation is a special case of general practical argumentation. Spaak argues, however, (A) that even if in some sense legal acts necessarily raise a claim to correctness, it does not follow that law has a dual nature; (B) that even if it did follow that law has a dual nature, it would not follow (i) that the separation thesis of legal positivism was false, or (ii) that legal argumentation was a special case of general practical argumentation; and (C) that this in turn suggests that constitutivists about practical reason are fighting an uphill battle.

This chapter focuses on the uses of the notion of ‘sources of law’ in continental analytical jurisprudence. It aims to illuminate the way legal theorists in the civil law world have grappled with the various aspects and meanings of this notion. In the first section, it shows that four different concepts of sources of law can be found in the literature: sources (1) as law-creating (f)acts, (2) as norms, (3) as authoritative texts or materials, and (4) as causal factors; it then goes on to show that the first concept is more fundamental than the three others and should have priority over them. In the second section, the chapter reviews the classical controversies regarding the various types of sources of law, such as the respective status of legislation, precedent, custom, legal doctrine, etc. It raises the puzzle of how various (f)acts (such as precedent) can be law-creating without being recognised as ‘formal’ sources of law and aims to explain how legal theorists can cope with it.

By the term ‘legal power’, we refer to a range of practices common to all modern legal systems in which persons are intentionally empowered by the legal system to bring about changes in it by affecting their own legal position or that of others. The fourteen essays included in this volume explore this fundamental concept through an approach to five major themes. The chapters of the first part deal with still open questions about the meaning of legal power and legal competence. The second part offers an analysis of the normativity of legal power. The third part is devoted specifically to exploring the relationship between legal power and constitutive norms. The fourth part is composed of chapters dealing with the analysis of legal offices and legal officers. Finally, the last part of this volume groups together chapters analysing various theories of legal power and legal competence.