The Metaphysics of Practical Rationality: Intentional and Deontic Cognition

Despite growing appreciation in recent decades of the importance of shared intentional mental states as a foundation for everything from divergences in primate evolution, to the institution of communal norms, to trends in the development of modernity as a sociopolitical phenomenon, we lack an adequate understanding of the relationship between individual and shared intentionality. At the same time, it is widely appreciated that deontic reasoning concerning what ought, may, and ought not be done is, like reasoning about our intentions, an exercise of practical rationality. Taking advantage of this fact, I use a plan-theoretic semantics for the deontic modalities as a basis for understanding individual and shared intentions. This results in a view that accords well with what we currently have reason to believe about the phylogenetic and ontogenetic development of norm psychology and shared intentionality in human beings, and where original intentionality can be understood in terms of the shared intentionality of a community.

Mīmāṃsā deontic reasoning using specificity: a proof theoretic approach

Over the course of more than two millennia the philosophical school of Mīmāṃsā has thoroughly analyzed normative statements. In this paper we approach a formalization of the deontic system which is applied but never explicitly discussed in Mīmāṃsā to resolve conflicts between deontic statements by giving preference to the more specific ones. We first extend with prohibitions and recommendations the non-normal deontic logic extracted in Ciabattoni et al. (in: TABLEAUX 2015, volume 9323 of LNCS, Springer, 2015) from Mīmāṃsā texts, obtaining a multimodal dyadic version of the deontic logic $$\mathsf {MD}$$ MD . Sequent calculus is then used to close a set of prima-facie injunctions under a restricted form of monotonicity, using specificity to avoid conflicts. We establish decidability and complexity results, and investigate the potential use of the resulting system for Mīmāṃsā philosophy and, more generally, for the formal interpretation of normative statements.

A Preference-Based Approach to Defeasible Deontic Inference

In this paper we present an approach to defeasible deontic inference. Given a set of rules R expressing conditional obligations and a formula A giving contingent information, the goal is to determine the most desirable outcome with respect to this information. Semantically, the rules R induce a partial preorder on the set of models, giving the relative desirability of each model. Then the set of minimal A models characterises the best that can be attained given that A holds. A syntactic approach is also given, in terms of maximal subsets of material counterparts of rules in R, and that yields a formula that expresses the best outcome possible given that A holds. These approaches are shown to coincide, providing an analogue to a soundness and completeness result. Complexity is not unreasonable, being at the second level of the polynomial hierarchy when the underlying logic is propositional logic. The approach yields desirable and intuitive results, including for the various “paradoxes” of deontic reasoning. The approach also highlights an interesting difference in how specificity is dealt with in nonmonotonic and deontic reasoning.

Deontic Moral Reasoning Task

Domain theory suggests that moral rules and conventions are perceived differently and elicit a different response. A special procedure was designed to test this hypothesis in a laboratory setting using a deontic reasoning task. The goal was to gain insight into the cognitive and metacognitive processes of deontic reasoning from simple deontic premises. In the 3x2x2 within-subjects design, we varied rule-content (moral, conventional, abstract), rule-type (obligation, permission) and the induced dilemma (punishment dilemma, reward dilemma). Participants (N = 78) were presented with 12 laws. After memorizing a law, eight cases were presented to participants so that they make a quick judgment. Participants were tasked with punishing rule-violators, ignoring rule-conformists, and rewarding rule-supererogation. Response times (RT) and accuracy were measured for each judgment, and final confidence was measured after a set of judgments. No differences were expected between rule-types, except for superior performance for moral content and punishment dilemmas. RT correlated negatively with confidence levels, while accuracy correlated positively. Moral reasoning was more accurate than conventional and abstract reasoning, and produced higher confidence levels. Better performance was found for punishment dilemmas than reward dilemmas, likely due to the presence of a cheater-detection module; but the differences were not found in moral reasoning. Moral reasoning was also independent of rule-type, while conventional and abstract reasoning produced superior performance in obligation-type than in permission-type rules. A large drop-off in accuracy was detected for rules that allowed undesirable behaviour, a phenomenon we termed the "deontic blind spot". However, this blind spot was not present in moral reasoning. Three lines of evidence indicate a qualitative difference between the moral and other deontic domains: (1) performance for moral content was independent of rule-type, (2) moral content produced an equal activation of violator- and altruist-detection modules, and (3) moral content produces higher levels of confidence.