Alan: An Action Language For Modelling Non-Markovian Domains

In this paper we present the syntax and semantics of a temporal action language named Alan, which was designed to model interactive multimedia presentations where the Markov property does not always hold. In general, Alan allows the specification of systems where the future state of the world depends not only on the current state, but also on the past states of the world. To the best of our knowledge, Alan is the first action language which incorporates causality with temporal formulas. In the process of defining the effect of actions we define the closure with respect to a path rather than to a state, and show that the non-Markovian model is an extension of the traditional Markovian model. Finally, we establish relationship between theories of Alan and logic programs.     

Admissibility of Cut in <Emphasis Type="Italic">LC</Emphasis> with Fixed Point Combinator

The fixed point combinator (Y) is an important non-proper combinator, which is defhable from a combinatorially complete base. This combinator guarantees that recursive equations have a solution. Structurally free logics (LC) turn combinators into formulas and replace structural rules by combinatory ones. This paper introduces the fixed point and the dual fixed point combinator into structurally free logics. The admissibility of (multiple) cut in the resulting calculus is not provable by a simple adaptation of the similar proof for LC with proper combinators. The novelty of our proof—beyond proving the cut for a newly extended calculus–is that we add a fourth induction to the by-and-large Gentzen-style proof. Presented by Robert Goldblatt     

Free Choice Permission is Strong Permission

Free choice permission, a crucial test case concerning the semantics/ pragmatics boundary, usually receives a pragmatic treatment. But its pragmatic features follow from its semantics. We observe that free choice inferences are defeasible, and defend a semantics of free choice permission as strong permission expressed in terms of a modal conditional in a nonmonotonic logic.     

On The Structure of Rational Acceptance: Comments on Hawthorne and Bovens

The structural view of rational acceptance is a commitment to developing a logical calculus to express rationally accepted propositions sufficient to represent valid argument forms constructed from rationally accepted formulas. This essay argues for this project by observing that a satisfactory solution to the lottery paradox and the paradox of the preface calls for a theory that both (i) offers the facilities to represent accepting less than certain propositions within an interpreted artificial language and (ii) provides a logical calculus of rationally accepted formulas that preserves rational acceptance under consequence. The essay explores the merit and scope of the structural view by observing that some limitations to a recent framework advanced James Hawthorne and Luc Bovens are traced to their framework satisfying the first of these two conditions but not the second.     

Mind,Brain, and Epistemologically Different Worlds

The reason why, since Descartes, nobody has found a solution to the mind–body problem seems to be that the problem itself is a false or pseudo-problem. The discussion has proceeded within a pre-Cartesian conceptual framework which itself is a source of the difficulty. Dualism and all its alternatives have preserved the same pre-Cartesian conceptual framework even while denying Descartes’ dualism. In order to avoid this pseudo-problem, I introduce a new perspective with three elements: the subject, the observed object, and the conditions of observation (given by the internal and external tools of observation). On this new perspective, because of the conditions of observation, the mind and the brain belong to epistemologically different worlds. An erratum to this article is available at .     

Reason and the Past: The Role of Rationality in Diachronic Self-Knowledge

Knowing one’s past thoughts and attitudes is a vital sort of self-knowledge. In the absence of memorial impressions to serve as evidence, we face a pressing question of how such self-knowledge is possible. Recently, philosophers of mind have argued that self-knowledge of past attitudes supervenes on rationality. I examine two kinds of argument for this supervenience claim, one from cognitive dynamics, and one from practical rationality, and reject both. I present an alternative account, on which knowledge of past attitudes is inferential knowledge, and depends upon contingent facts of one’s rationality and consistency. Failures of self-knowledge are better explained by the inferential account.     

Omitting Data—Ethical or Strategic Problem?

Omitting experimental data is often considered a violation of scientific integrity. If we consider experimental inquiry as a questioning process, omitting data is seen to be merely an example of tentatively rejecting (‘bracketing’) some of nature’s answers. Such bracketing is not only occasionally permissible; sometimes it is mandated by optimal interrogative strategies. When to omit data is therefore a strategic rather than ethical question. These points are illustrated by reference to Millikan’s oil drop experiment.