Situationist deontic logic (Q1368755)

Situationist deontic logic is deontic logic restricted in application to single situations and single sets of alternatives, thus taking no account of change or variation of agent's perspective, and representing no general norms. Even within this limited domain, standard deontic logic exhibits noteworthy problems. This paper offers a diagnosis of SDL's failure and suggests an alternative basis for deontic logic. In SDL prescriptive statements \(O \alpha\) are taken to be equivalent to sentences saying \(\alpha\) is the best of all alternatives \(\beta\), that for any such \(\beta\), it is not the case that \(\beta R\alpha\), where \(R\) is an appropriate relation of (weak) preference. The problem, giving rise to the well-known paradoxes as well as failures with respect to supererogation, is that the predicate `best' is positive with respect to \(R\), i.e., that if \(O\beta\) and \(aR\beta\) then \(O\alpha\). In place of positivity it is suggested that prescriptive predicates be contranegative with respect to \(R\), i.e., that if \(O\alpha\) and \((\neg \alpha) R(\neg \beta)\), then \(O\beta\). Various preference relations are then described, and the several principles of standard deontic logic are shown to correspond to particular conditions on the relation \(R\). By appropriate choice of \(R\), then, one may reject the principles that give rise to SDL's problems.