Deontic Tense Logic With Historical Necessity, Frame Constants, and a Solution to the Epistemic Obligation Paradox (The "Knower")
2014 (English)In: Theoria, ISSN 0040-5825, E-ISSN 1755-2567, Vol. 80, no 4, 319-349 p.Article in journal (Refereed) Published
In an earlier paper by the author, angstrom qvist (1999), I presented an approach to the logic of historical necessity, or inevitability, in the sense of a two-dimensional combination of tense and modal logic for worlds, or histories, with the same time order, known as T x W logic. Distinctive features of that approach were, apart from its two-dimensionality, its being based on discrete and finite time, and its use of so-called systematic frame constants in order to enable us to indicate longitudes (x-values) and latitudes (y-values) of any points in the co-ordinate systems under consideration. This led us to study and axiomatize an infinite hierarchy HTWxy of two-dimensional modal tense logics with the characteristic operators for historical necessity and possibility added to the original basic vocabulary. The main purpose of the present paper is then twofold: (A) to extend the logics HTWxy to the interesting branch of philosophical logic constituted by deontic logic as combined with tense (or temporal) logic; and (B) to deal with a curious puzzle known as the so-called epistemic obligation paradox - a well known stumbling-block in this area of research in philosophical logic. We argue for a solution to both these problems, which appeals to a new infinite hierarchy DHTWxym of extensions of the HTWxy in the sense of logics combining dyadic deontic modalities with temporal ones such as those for historical necessity and other two-dimensional modalities.
Place, publisher, year, edition, pages
2014. Vol. 80, no 4, 319-349 p.
historical necessity, finite two-dimensional co-ordinate system, frame constants, paradoxes of deontic logic, Hansson - Bengt, Hansson - Sven Ove, Spohn - Burgess, Alchourron and Bulygin
IdentifiersURN: urn:nbn:se:uu:diva-237889DOI: 10.1111/theo.12036ISI: 000343917500003OAI: oai:DiVA.org:uu-237889DiVA: diva2:770893