This book investigates the way law can affect practical reasons. What difference can legal requirements - be they traffic rules, tax laws, work safety regulations, or others - make to normative reasons relevant to our action? Do they give reasons for action that should be weighed among all other reasons that were applicable before their enactment? Or can they, instead, exclude and take the place of some other reasons? The book critically examines some of the existing answers and puts forward an alternative account of the relation between law and practical reason.
At the outset, two competing positions are pitted against each other: first, the view taken by Joseph Raz, that when the law satisfies certain conditions that endow it with legitimate authority, it acquires pre-emptive force, namely it constitutes reasons for action that exclude and take the place of some other reasons; second, an antithetical position, according to which legal requirements cannot exclude otherwise applicable reasons, but can at most provide us with reasons that operate, and compete with opposing reasons, in terms of their weight.
These two positions are examined from several perspectives, such as justified disobedience cases, law's conduct-guiding function, and the phenomenology associated with authority. It is found that, although each of the above positions offers insight into the relation between law and practical reasons, they both suffer from significant flaws. These observations lay the basis on which, in the final part of the book, an alternative position is put forward and defended. On this position, the existence and operation of a reasonably just and well functioning legal system constitutes some reasons that are neither ordinary reasons for action nor pre-emptive ones, but rather reasons to adopt a disposition that will generally incline its possessor towards compliance with the system's requirements.