Legal parallelism: How to understand the relationships and distinctions between law and morality, as well as their respective authorities

Extensions of contemporary insights from evolutionary psychology and game theory suggest that we employ a particular kind of psychological state---an "obligatum"---to identify and respond to obligations. This explains why law and morality share a number of deep structural parallels. Both (i) purport to provide us with reasons to act; that are (ii) exclusionary; (iii) agent-centered; (iv) have general application; and (v) are sensitive to certain standard excuses. Both (vi) are bound up with reactive attitudes; and (vii) share a special terminology that is (viii) essentially contestable and (ix) supervenes on natural facts. Our competence to respond to obligations has this deep structure, which is akin to Chomsky's deep structure of language.; The obligata that give life to our moral and legal practices are nevertheless distinct, and the dissertation develops a purely naturalistic account of the distinction. The respective obligata function to resolve different classes of social contract problems, and are coordinated via different psychosocial mechanisms, which allow for distinctive practices of moral and legal judgment. Existing accounts of these attitudes make it difficult or impossible to distinguish moral from legal judgment non-circularly and naturalistically. The proposed account makes such a distinction, thus clarifying the relationships and differences between moral and legal judgment.; Importantly, the particular evolutionary explanations offered of obligata are not debunking. They instead vindicate the view that we have special capacities of moral and legal judgment that allow us to identify and respond appropriately to certain complex natural properties of actions, which in fact have the right kind of authority to guide us practically. We are, however, also naturally inclined toward certain practical illusions in both spheres---analogues of the familiar optical illusions of ordinary perception. One is that law's authority reduces to morality's, and the dissertation argues against this view and some of its effects on leading views of Dworkin and Raz. In modern circumstances, it is urgent that we credit law's independent but parallel source of authority because our moral psychologies incline us toward certain forms of systematic error, and law is needed to require us, legitimately, to engage in more robust tolerance.