Stephen Hawking has argued that universes containing evaporating black holes can evolve from pure initial states to mixed final ones. Such evolution is non-unitary and so contravenes fundamental quantum principles on which Hawking's analysis was based. It disables the retrodiction of the universe's initial state from its final one, and portends the time-asymmetry of quantum gravity. Small wonder that Hawking's paradox has met with considerable resistance. Here we use a simple result for C*-algebras to offer an argument for pure-to-mixed state (...) evolution in black hole evaporation, and review responses to the Hawking paradox with respect to how effectively they rebut this argument. (shrink)

The purpose of this paper is to discuss the various types of physical universe which could exist according to modern mathematical physics. The paper begins with an introduction that approaches the question from the viewpoint of ontic structural realism. Section 2 takes the case of the `multiverse' of spatially homogeneous universes, and analyses the famous Collins-Hawking argument, which purports to show that our own universe is a very special member of this collection. Section 3 considers the multiverse of all solutions (...) to the Einstein field equations, and continues the discussion of whether the notions of special and typical can be defined within such a collection. (shrink)

In this paper I will present conceptions of state reduction and particle and/or system localization which render these subjects fully compatible with the general requirements of a relativistic, i.e. Lorentz invariant, quantum theory. The approach consists of a systematic generalization of the concepts of initial data assignment at definite times, initiation and completion of measurements at definite times, and dynamical evolution as time dependence, to the concepts of initial data assignment on arbitrary space-like hyperplanes, initiation and completion of measurements on (...) arbitrary space-like hyperplanes, and dynamical evolution as space-like hyperplane dependence, respectively. I also briefly discuss the superluminal propagation which emerges from the localization study and the manner in which causal anomalies are nevertheless avoided. (shrink)

A vast amount of ink has been spilled in both the physics and the philosophy literature on the measurement problem in quantum mechanics. Important as it is, this problem is but one aspect of the more general issue of how, if at all, classical properties can emerge from the quantum descriptions of physical systems. In this paper we will study another aspect of the more general issue-the emergence of classical chaos-which has been receiving increasing attention from physicists but which has (...) largely been neglected by philosophers of science. (shrink)

The main theme of these lectures is man's struggle to understand himself as a social being. A discussion of the major problems confronting man in his attempts to come to grips with the modern social world ends with a plea for liberalism and rationalism as the political and intellectual foundations of freedom and progress.

The long established but infrequently discussed dependence of Lorentz boost generators on the presence and nature of interactions is reviewed in this tutorial note. The last third of the note presents a discussion of the covariant transformation and evolution equations for the non-conserved partial generators of the inhomogeneous Lorentz group for interacting subsystems.

Many have interpreted symbolic material culture in the deep past as evidencing the origins sophisticated, modern cognition. Scholars from across the behavioural and cognitive sciences, including linguists, psychologists, philosophers, neuroscientists, primatologists, archaeologists, and palaeoanthropologists have used such artefacts to assess the capacities of extinct human species, and to set benchmarks, milestones, or otherwise chart the course of human cognitive evolution. To better calibrate our expectations, the present paper instead explores the material culture of three contemporary African forager groups. Results show (...) that, although these groups are unequivocally behaviourally modern, they would leave scant long-lasting evidence of symbolic behaviour. Artefact sets are typically small, perhaps as a consequence of residential mobility. When traded materials are excluded, few artefacts have components with moderate–to–strong taphonomic signatures. The present analyses show that artefact function influences preservation probability, such that utilitarian tools for the processing of materials and the preparation of food are disproportionately likely to contain archaeologically traceable components. There are substantial differences in material use among populations, which create important population-level variation in preservation probability, independent of cognitive differences. I discuss the factors – cultural, ecological, and practical – that influence material choice. In so doing, I highlight the difficulties of using past material culture as an evolutionary or cognitive yardstick. (shrink)

Contemporary debates about mechanisms in the philosophy of science raise the question about the relation between constitutive and causal relations. These discussions so far have not received Ernest Sosa’s “Varieties of Causation‘, which addresses similar questions from a metaphysical point of view. The present paper reconstructs and evaluates Sosa’s arguments from the perspective of the contemporary debates. We argue that while Sosa’s arguments are probably not suited to advance the current debate, his claim that there are different varieties of causation (...) might be an interesting idea to consider for those who assume that there are interlevel causal relations. (shrink)

Challenges current interpretations of Frege's work arguing that they anachronistically project late twentieth century concerns and categories onto the thought of a nineteenth-century mathematical logician.

The article develops an Ignatian perspective, from within which it then interprets and amplifies Bernard Lonergan's intellectual project. Exploiting recent analyses of medieval memorial culture and the rhetorical dynamicsof monastic spiritual practice, the article highlights the performative quality of key Ignatian texts, paying particular attention to the categories of ornamentation and ordering . Appreciating the vantage afforded by heightened self-presence, reflexive knowledge and intentional praxis, the article then explores Lonergan's project, employing the rubric of ornamentation and ordering to investigate the (...) interaction between cognitional activity and the matrix of desire informed by unbounded wonder, specific desires and distorting bias. Formative self-appropriation is then considered as a religious process, in which the self gathers the resources of Scripture and tradition to compose a creative faith response to the divine initiative of transforming love, a response that unfolds more fully in the co-development of personal, social and cultural activity. (shrink)

In the nineteenth century, Henry Sidgwick struggled with the apparent paradox that utilitarians might only attain their goal if they renounced utilitarianism in practice; he also noticed a parallel problem that anticipated what has been called the ‘paradox of desire’ in Buddhist ethics – the paradox that desiring desirelessness is self-defeating. In fact, he regarded only the latter as a genuine paradox. I consider three approaches that might mitigate the problematicimplications for Buddhist ethics and certain forms of consequentialism. One approach (...) draws on recent defences of moral realism that find echoes in at least one Buddhist tradition. The other two draw on what I call the ‘comparative cartography of ethical concepts’; one is due to David Webster, who compares Western andPali-based Buddhist concepts, while the other offers an extension of his approach, comparing ‘thick’ and ‘thin’ ethical concepts, again mainly in the context of ancient Indian Buddhism. I argue that these latter two approaches offer promising defences of Buddhist ethics against objections based on the so-called ‘paradox of desire’. (shrink)