The modal logician's notion of possible world and the computer scientist's notion of state of a machine provide a point of commonality which can form the foundation of a logic of action. Extending ordinary modal logic with the calculus of binary relations leads to a very natural logic for describing the behavior of computer programs.

Habermas élabore une théorie radicale de la démocratie qui entend répondre aux défis posés tant par la mondialisation économique que par la tentation de repli des « peuples » qui cherchent à retrouver une souveraineté perdue. Une telle théorie, qui prend une forme délibérative, projette la démocratie dans la constitutionnalisation du droit international, et implique une perspective cosmopolitique. Dans ce cadre, la réflexion sur la politique européenne et ses institutions est centrale, et permet de montrer que la théorie critique n’a (...) rien perdu de sa lucidité quand il s’agit de mettre en garde notamment contre un « fédéralisme postdémocratique de l’exécutif » dans lequel l’Europe risque de se perdre. (shrink)

Dynamic algebras combine the classes of Boolean (B 0) and regular (R ; *) algebras into a single finitely axiomatized variety (B R ) resembling an R-module with scalar multiplication . The basic result is that * is reflexive transitive closure, contrary to the intuition that this concept should require quantifiers for its definition. Using this result we give several examples of dynamic algebras arising naturally in connection with additive functions, binary relations, state trajectories, languages, and flowcharts. The main result (...) is that free dynamic algebras are residually finite (i.e. factor as a subdirect product of finite dynamic algebras), important because finite separable dynamic algebras are isomorphic to Kripke structures. Applications include a new completeness proof for the Segerberg axiomatization of prepositional dynamic logic, and yet another notion of regular algebra. (shrink)

Environment and Philosophy provides an accessible introduction to the radical challenges that environmentalism pose to concepts that have become almost second nature in the modern world. Written in an accessible way for those without a background in philosophy, this text examines ways of thinking about ourselves, nature and our relationship with nature.

For Leibniz, it was a requirement upon the `fundamentally real' to have a `principle of unity'. What does this mean?One general point is that Substance cannot be understood as pure extension. But there is a particular point about cohesion: a real thing had to have some means by which its parts were stuck together. But Leibniz' insistence on `unity' is also an insistence on indivisibility. Under this head there is first the point that there appears to be a contradiction between (...) extension and being incapable of being cut in two. Second, Leibniz uses the notion of `indivisibility' to mark the following distinction among things made up of parts: those which cannot be split without being destroyed; and the rest . To be `indivisible' is to be of the first type. Leibniz' insistence that the truly real must be `indivisible' is then his insistence that the truly real, if it is made up of parts, must be a thing with `integrity', i.e. not an aggregate.What does Leibniz think of as the connection between what is truly real and the possession of `integrity'? He took from Scholasticism the doctrine that action is necessarily attributed to a substance having `integrity', contructing what was in effect a theory of action with two parts: only self-subsistent substances can act; and an action is an origination of change. Leibniz thus insists that self-subsistent substances must be indivisible, in the sense that they cannot be mere aggregates. Aggregates cannot act, and self-subsistence in effect is the capacity for action. This is the most fundamental reason Leibniz had for insisting that the truly real must have a `principle of unity'.It is misleading to speak of Leibniz reintroducing the Scholastic form-and-matter conception of substance for the following reasons: the Scholastic `form' precisely lacked a `principle of action'; and during the period when it is suggested that Leibniz' conception was essentially Scholastic he was defending the view that what his `form' informed was not matter at all but what he called a `metaphysical point'. (shrink)

We give an example of a polynomial time algorithm for a particular algorithmic problem involving vagueness and visual indiscriminability, namely sock sorting.

It has been claimed that in a single line of development the science of taxonomy stretches from Aristotle to the present day and that the Aristotelian 'essence' lies at the heart of much later thought about grouping. I try to establish some basic features of Aristotle's conception of 'essence', and then consider in more detail the conception of essence that entered into 18th century thought about classification, with a view to establishing discontinuities. 18th century thought, I note, has two kinds (...) of essence, real and nominal, and I consider the view that a 'natural' classification in that context should be understood as one which is based on real essences. In place of this thesis, I advocate the view that the hidden foundation of 18th century systematics is a very restrictive articulation of the visual field which gives sense to the possibility of grouping according to the sum total of observable similarities and differences: and that it is this possibility that a 'natural' classification was conceived of as realising. (shrink)

The rationale for the common rejection of classical societal functionalism is that it entails treating a society as an intelligent purposer, capable of directing its own internal organization in furtherance of survival. But a more acceptable alternative account of the origins of a society's functional organization is conceivable: the individual unconsciously recognizes the needs of his group and directs his behaviour so that they are met. The plausibility of this explanation hangs on whether selection between groups occurs to any significant (...) extent, however, and it is therefore on this question that the plausibility of classical societal functionalism itself depends. (shrink)

Published in the year 2004, Philosophy and the Social Sciences is a valuable contribution to the field of Sociology.

An appeal to the inexplicable has always been a favourite tactic of the Supernaturalist; and even today those Supernaturalists that remain seem to derive some comfort from it. During the eighteenth and nineteenth centuries, for example, the orthodox Protestant apologetic in this country laid great stress on the ‘inexplicable’ events allegedly associated with Christ's life as anthenticating the truths of revelation. A more general thesis has been put forward as often, and even more often assumed: that the occurrence of inexplicable (...) events demonstrates the reality of a ‘spiritual’ realm. And in current literature we can find it claimed that the hegemony of science or the tenability of materialism is threatened by those inexplicabilities which are now known as the phenomena of ESP. (shrink)