On the Semantics of the Ought-To-Do

Abstract

Deontic concepts like ought, right, obUgation, forbidden, and permissible have benefited from the philosophically exciting work in the semantics of modal concepts done by Kangerl, Hintikka 2 , Kripke 3 , Montague 4 and others. Their semantics illuminates both the topic and the contribution of the standard axiomatic approach to deontic logic: the topic is what philosophers used to call the Ought-to-be. On the other hand, the non-standard approach represented by early axiomatic deontic systems of ours deals with the Ought-to-do. Thus, rather than competing with the standard approach to deontic logic, our non-standard approach complements it. This can, however, be seen only by providing our non-standard approach with a minimum of semantical foundations. This is precisely what this essay attempts to do. We shall also provide a rationale for our non-standard semantical system by formulating some proto-philosophical data that both guide the development of the system and serve as tests of adequacy for it. In fact, our concern is primarily philo-sophieal, not technical. There are, of course, important general philosophical reasons for developing divergent systems: (i) our appreciation of standard systems is enhanced by contrasting them with non-standard ones, and (ii) our understanding of aset of concepts improves by seeing them in different lights. 1. Ought-To-Be and Ought-To-Do