The paper presents a logical treatment of actions based on dynamic logic. This approach makes it possible to reflect clearly the differences between static and dynamic elements of the world, a distinction which seems crucial to us for a representation of actions.Starting from propositional dynamic logic a formal system (DLA) is developed, the programs of which are used to model action types. Some special features of this system are: Basic aspects of time are incorporated in DLA as far as they (...) are needed for our purpose. Names for states and for instants are simulated by formulas. It is possible to express formally that a formula is satisfiable or valid. A special program is introduced to reflect developments which are not caused by an official agent but by external influences. (shrink)

This paper investigates the semantic treatment of conditional obligation, explicit permission (often called positive permission), and prohibition based on models with agents and branched time. In such models branches (rather than moments) are taken as basic, and the branching provides a way to represent the indeterminism which is normally presupposed by talk of free will, responsibility, action and ability. Careful treatment of the relation between ability and responsibility avoids many common problems with accounts of conditional obligation. Recognition of the generality (...) often involved in conditional obligations makes possible a sensitive way of expressing some kinds of general prohibitions, which in turn makes it possible to account for the special role of explicit permission. (shrink)

I offer you some theories of intellectual obligations and rights (virtue Ethics): initially, RBT (a Right to Believe Truth, if something is true it follows one has a right to believe it), and, NDSM (one has no right to believe a contradiction, i.e., No right to commit Doxastic Self-Mutilation). Evidence for both below. Anthropology, Psychology, computer software, Sociology, and the neurosciences prove things about human beliefs, and History, Economics, and comparative law can provide evidence of value about theories of rights. (...) However, insofar as we have methods within Philosophy to help us formulate precise concepts of 'belief' and 'rights', methods that also help us to prove links (or absence thereof) amongst families of concepts of rights and belief, our discipline is in and of itself capable of sound reasoning about issues as puzzling as the following. Suppose a Jane who does not believe in God yet who believes she ought to so believe: Jane is undergoing doxastic moral regret (moral regret for lack of faith). We have all known such Janes and perhaps at one time or another even been one. Paradox: given RBT and NDSM, Jane as described not only does not exist, Jane cannot exist. Thus, to enrich the ways in which Philosophy need not get all its evidence from other academic disciplines, I present a brief introduction to what I call Neutral Universal Frames (NUFs). NUFs solve hard puzzles about interactions among modal concepts of belief and rights, concepts that occur in RBT, NDSM and the description of our Janes. NUFs for theories precisely articulated via any two or more modal concepts are a powerful and immensely general set of tools enabling us to define rich theories of truth ("models on frames") to test philosophical theories for internal consistency and to prove the existence of connections (or absence thereof) amongst alternative articulations of philosophical theories. NUFs thereby add to the constructive knowledge producing way Logics intersect with Philosophy of Religion. And we will soon see why Jane, be she named 'Jane' or known simply as you: cannot exist. Read on at your own risk. (shrink)

In this paper, we give an alternative semantics to the non-normal logic of knowing how proposed by Fervari et al., based on a class of Kripke neighborhood models with both the epistemic relations and neighborhood structures. This alternative semantics is inspired by the same quantifier alternation pattern of ∃∀\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\exists \forall $$\end{document} in the semantics of the know-how modality and the neighborhood semantics for the standard modality. We show that this new semantics (...) is equivalent to the original Kripke semantics in terms of the validities. A key result is a representation theorem showing that the more abstract Kripke neighborhood models can be represented by the concrete Kripke models with action transitions modulo the valid formulas. We prove the completeness of the logic for the neighborhood semantics. The neighborhood semantics can be adapted to other variants of logics of knowing how. It provides us a powerful technical tool to study these logics while preserving the basic semantic intuition. (shrink)

The use of predicate and sentential operators to express the practical modalities -- ability, control, openness, etc. -- has given new life to a fatalistic argument against determinist theories of responsible agency. A familiar version employs the following principle: the consequences of what is unavoidable (beyond one's control) are themselves unavoidable. Accordingly, if determinism is true, whatever happens is the consequence of events in the remote past, or, of such events together with the laws of nature. But laws and the (...) remote past are not under our control and, by the principle, neither are their consequences. Therefore, none of our choices and actions, nor anything that results from them, is under our control.1 Whether refinements of the closure principle underlying this unavoidability argument are acceptable depends upon the precise sense of 'consequence' and 'unavoidable' involved. Roughly, a proposition P is a consequence of a set of propositions M iff it is impossible that P be false when each member of M is true, or, conversely, when M necessitates P. Since P is unavoidable for S when P is true and S is (was) unable to prevent P from being true, it might seem that if P is unavoidable the same should hold of what is necessitated by P. There is, in fact, 1 an easy defense of the principle which utilizes the incompatibilist condition that S is able to do action K only if it is as yet undetermined whether or not S will K. With it, there is no question but that one is unable to accomplish what is already determined by what one was unable to prevent. Of course, this reasoning is unlikely to impress the compatibilist who rejects the condition outright and, expectedly, it is not the procedure of the proponents of the unavoidability argument. The latter might rest content with appeals to intuition, but more significant are defenses of the closure principle and independent derivations of the unavoidability argument that rely upon distinct principles concerning the logic of the practical modalities, for example, closure of ability under entailment (Cross 1986, Brown 1988) or, claims about the "fixity of the past" and the "inescapability of laws" (Ginet 1990).. (shrink)

The basic bimodal systemK/K can be interpreted as an analysis of the logic of ability developed in [1]. Where in [1] we would express the claimI can bring it about that P using the formula, with its non-normal operator, we will now use the formula. Here is a normal alethic possibilitation operator.is a normal necessitation operator, but it is independent of, and not subject to an alethic interpretation. Rather, is interpreted to meanI bring it about that P. The result is (...) a simplification and clarification of a combined logic of ability and action like that in [2], but employing only normal operators.A number of extensions of the basic systemK/K are constructed, first by strengthening the two normal sublogics independently and then by linking the two sublogics via axiom schemata involving both operators. The result is a series of increasingly strong systems which more and more adequately fulfill our expectations for a satisfactory logic of action and ability. (shrink)

Normal systems of modal logic, interpreted as deontic logics, are unsuitable for a logic of conflicting obligations. By using modal operators based on a more complex semantics, however, we can provide for conflicting obligations, as in [9], which is formally similar to a fragment of the logic of ability later given in [2], Having gone that far, we may find it desirable to be able to express and consider claims about the comparative strengths, or degrees of urgency, of the conflicting (...) obligations under which we stand. This paper, building on the formalism of the logic of ability in [2], provides a complete and decidable system for such a language. (shrink)