This book is a systematic defense of realism concerning reasons for action that challenges both expressivism and constructivism. Chapter 1 outlines the constraints that Scanlon takes to to be relevant to his project and distinguishes some of the opposing views. Constraints related to the ontology of reasons for action are addressed in Chapter 2. In this chapter, Scanlon aims to defend his view against Mackie's charge of 'queerness' concerning normative facts. The account of reasons for action developed in this chapter is premised on the idea of different domains of inquiry, domains concerning, for instance, mathematics, natural sciences, normative considerations. Scanlon argues that each domain has a certain independence from the others and that we should not confuse the world of the natural sciences with all that there is. The latter field is defined by all those entities to which we are committed to as a result of our commitment to well grounded theories in each of these domains. While this may seem to beg the question, since it is seems unlikely that all of Scanlon's opponents would accept this view of the normative domain, it also seems quite plausible to say that the reasons that we have to eat, pay taxes, or listen to enjoyable music, if they are well grounded, are largely independent of the findings of, neuroscience, for instance. In other words, if we have good reason to x, spelled out in terms of those ordinary considerations that make up our reasons for action, then we don't need to worry about external objections to these reasons. Scanlon acknowledges that domains are not impermeable but does not seek to address particular jurisdictional disputes.
Chapter 3 is one of the more interesting chapters in the book. Here Scanlon, successfully it seems, systematically challenges expressivism arguing that it is inadequate to account for our normal discourse about reasons, especially when giving advice and justifying ourselves to others. Chapter 4 addresses epistemological questions. Using an analogy with reasoning about set theory, Scanlon argues that their is nothing odd about our cognitive 'access' to reasons for action. Since we reason about reasons for action in a manner not unlike any other type of reasoning. We consider the upshot of certain facts or courses action and find certain reasons more plausible than others. We consider what principles would justify our judgments and consider the further implications of those principles. This chapter employs Rawls's notion of reflective equilibrium to spell this out. Scanlon concludes this chapter by arguing that constructivism fails as an account of reasons for action, since the Categorical Imperative is not constitutive of rational agency (a point he presupposes but does not argue in depth) and rival constructivist views are lacking. While greater consideration of the Kantian position is really needed, Scanlon's claim is not implausible. In the absence of a general constructivist procedure to derive reasons for action, our efforts must be seen to be directed toward discovering the relevant reasons for action in each varied context. The final chapter considers the varying strength of reasons for action.
In this book, Scanlon offers a powerful critique of expressivism and a defense of a realistic view of reasons for action. There is a certain quietism in Scanlon's approach, recalling McDowell and perhaps Wittgenstein, in that he ultimately provides a defense of ordinary reasoning about what one has reason to do. In defending the reasoning of ordinary persons, he does not offer some theory to explain why those reason should be treated as meaningful. Instead, he offers grounds for thinking that we don't need any additional reasons for appreciating our reasons for action.