Alasdair Richmond introduces some famous paradoxes about time travel.

Following on from Nick Bostrom's discussion of the Doomsday argument, Alasdair Richmond considers how anthropic reasoning can lead from Doomsday to some odd conclusions about computation and our place in reality.

Modern epistemology has run into several paradoxes in its efforts to explain how knowledge acquisition can be both socially based and still able to determine objective facts about the world. In this important book, Richmond Campbell attempts to dispel some of these paradoxes, to show how they are ultimately just "illusions of paradox," by developing ideas central to two of the most promising currents in epistemology: feminist epistemology and naturalized epistemology. Campbell's aim is to construct a coherent theory of (...) knowing that is feminist and "naturalized." Illusions of Paradox will be valuable for students and scholars of epistemology and women's studies. (shrink)

1 Background for the Uninitiated RICHMOND CAMPBELL Paradoxes are intrinsically fascinating. They are also distinctively ...

We present a unified empirical and philosophical account of moral consistency reasoning, a distinctive form of moral reasoning that exposes inconsistencies among moral judgments about concrete cases. Judgments opposed in belief or in emotion and motivation are inconsistent when the cases are similar in morally relevant respects. Moral consistency reasoning, we argue, regularly shapes moral thought and feeling by coordinating two systems described in dual process models of moral cognition. Our empirical explanation of moral change fills a gap in the (...) empirical literature, making psychologically plausible a defensible new model of justified moral change and a hybrid theory of moral judgment. (shrink)

My chief aim has been to convey the thought that the application of model theoretic techniques to natural languages needn't force a distortion of intentional phenomena. I hope that at least I have succeeded in accomplishing this.

The premises that a four foot man is short and that a man one tenth of an inch taller than a short man is also short entail by universal instantiation and "modus ponens" that a seven foot man is short. The negation of the second premise seems to entail there are virtually no borderline cases of short men, While to deny the second premise and its negation conflicts with the principle of bivalence, If not excluded middle. But the paradox can (...) be dissolved without resort to degrees of truth or any non-Classical system of logic. If some true predications can be semantically uncertain in a sense suitable for defining borderline cases, The second premise can be denied without denying the vagueness of "short" or reintroducing a sorites paradox along with higher order borderline cases. (shrink)

It is more than a half-century since Nelson Goodman [1955] applied what we call the Reflective Equilibrium model of justification to the problem of justifying induction, and more than three decades since Rawls [1971] and Daniels [1979] applied celebrated extensions of this model to the problem of justifying principles of social justice. The resulting Wide Reflective Equilibrium model (WRE) is generally thought to capture an acceptable way to reconcile inconsistency between an intuitively plausible general principle and an intuitively plausible judgment (...) about a particular case. Recently a different model for reconciling moral inconsistency has emerged: Moral Consistency Reasoning [Campbell and Kumar 2012, 2013a; Kumar and Campbell 2012; Campbell 2009: 86?7; Campbell and Woodrow 2003; Wong 2002]. MCR applies when two moral judgments give opposing assessments of (what appear to be) relevantly similar particular cases. Though WRE and MCR are strikingly different, each arguably captures a rationally acceptable method for reconciling moral inconsistency. Moreover, as will be shown, they function in complementary ways. Are they parts of a more comprehensive model of moral reasoning in the face of inconsistency that would explain the attractions of each? This essay first spells out the relevant differences between the models and then formulates a more general model of moral reasoning in the face of inconsistency. ?1 reviews the emergence of Goodman's model that he offers in the spirit of epistemology naturalized, almost a decade before Quine coined the term [1969a]. ?2 analyses six salient features of WRE to be compared with six contrasting features of MCR in ?3. ?4 presents the general model. (shrink)

In Kitcher’s ‘pragmatic naturalism’ moral evolution consists in pragmatically motivated moral changes in response to practical difficulties in social life. No moral truths or facts exist that could serve as an ‘external’ measure for moral progress. We propose a psychologically realistic conception of moral objectivity consistent with this pragmatic naturalism yet alive to the familiar sense that moral progress has an objective basis that transcends convention and consensus in moral opinion, even when these are products of serious, extended and collaborative (...) reflection. (shrink)

Early attempts at combining multiple inheritance with nonmonotonic reasoning were based on straightforward extensions of tree-structured inheritance systems, and were theoretically unsound. In The Mathcmat~'cs of Inheritance Systcrns, or TMOIS, Touretzky described two problems these systems cannot handle: reasoning in the presence of true but redundant assertions, and coping with ambiguity. TMOIS provided a definition and analysis of a theoretically sound multiple inheritance system, accom-.

Moral knowledge appears to require moral judgments to be states of belief, yet they must at the same time be states of desire and feeling if they embody the motivation that we feel when we make moral judgments. How can the same judgment be a state of belief and a state of desire or feeling, simultaneously? [...] This problem may be resolved, I shall contend, by understanding moral judgments to be complex, multifunctional states that normally comprise both states of belief (...) that represent possible moral truths and states of emotion and motivation. (shrink)

Might time be multi‐dimensional? In exploring this question, this paper uses a thought‐experiment about dimensionality, H. G. Wells' ‘The Plattner Story’. Plattner has his left and right sides transposed after a trip through a fourth spatial dimension, a change with independent empirical consequences. This example is then generalised to reversals of the directions of time and entropy. Finally, this thought‐experiment is related to relativistic theories of time and the possibility of preserving causality in a temporally multi‐dimensional framework.

A familiar position regarding the evolution of ethics is that biology can explain the origin of morals but that in doing so it removes the possibility of their having objective justification. This position is set fourth in detail in the writings of Michael Ruse but it is also taken by many others, notably, Jeffrie Murphy, Andrew Oldenquist, and Allan Gibbard, I argue the contrary view that biology provides a justification of the existence of morals which is objective in the sense (...) of being independent of people's moral views and their particular desires and preferences. Ironically, my argument builds on the very premises which are supposed to undermine the objectivity of morals. But my argument stops short of claiming that biology can give us a basis for justifying some particular system of morals. Drawing on an analogy with social contract theory, I offer a general reason why this more ambitious project cannot be expected to succeed if the argument is pursued along the same lines. Finally, I give reasons why the possibility of objective justification for a particular morality cannot be ruled out in general on evolutionary grounds. (shrink)

This chapter presents an overview of the issues that arise when logic is used in helping to understand problems in intelligent reasoning and to guide the design of mechanized reasoning systems. It provides some historical and technical details concerning nonmonotonic logic and reasoning about action and change, a topic that is not only central in artificial intelligence but that is normally of considerable interest to philosophers. The remaining sections provide brief sketches of selected topics, with references to the primary literature.

In the early years of Mendelism, 1900-1910, William Bateson established a productive research group consisting of women and men studying biology at Cambridge. The empirical evidence they provided through investigating the patterns of hereditary in many different species helped confirm the validity of the Mendelian laws of heredity. What has not previously been well recognized is that owing to the lack of sufficient institutional support, the group primarily relied on domestic resources to carry out their work. Members of the group (...) formed a kind of extended family unit, centered on the Batesons' home in Grantchester and the grounds of Newnham College. This case illustrates the continuing role that domestic environments played in supporting scientific research in the early 20th century. (shrink)

For as long as there have been theories about common knowledge, they have been exposed to a certain amount of skepticism. Recent more sophisticated arguments question whether agents can acquire common attitudes and whether they are needed in social reasoning. I argue that this skepticism arises from assumptions about practical reasoning that, considered in themselves, are at worst implausible and at best controversial. A proper approach to the acquisition of attitudes and their deployment in decision making leaves room for common (...) attitudes. Postulating them is no worse off than similar idealizations that are usefully made in logic and economics. (shrink)

The interpretation of indirect discourse is one of the most persistent and pervasive themes in post-Fregean semantics. Since Frege we have managed to learn a good deal about the workings of various technical approaches to indirect discourse, but fundamental philosophical issues have remained unresolved.

This paper proposes a formalization of ability that is motivated in part by linguistic considerations and by the philosophical literature in action theory and the logic of ability, but that is also meant to match well with planning formalisms, and so to provide an account of the role of ability in practical reasoning. Some of the philosophical literature concerning ability, and in particular [Austin, 1956], suggests that some ways of talking about ability are context-dependent. I propose a way of formalizing (...) this dependency. (shrink)

In June 1909, scientists and dignitaries from 167 different countries gathered in Cambridge to celebrate the hundredth anniversary of Charles Darwin’s birth and the fiftieth anniversary of the publication of Origin of Species. The event was one of the most magnificent commemorations in the annals of science. Delegates gathered within the cloisters of Cambridge University not only to honor the “hero” of evolution but also to reassess the underpinnings of Darwinism at a critical juncture. With the mechanism of natural selection (...) increasingly under attack, evolutionary theory was in disarray. Against this backdrop, biologists weighed the impact of several new developments—the rediscovery of Mendel’s laws of heredity, de Vriesian mutation theory, and the linkage of sex‐cell division to the mechanism of heredity. The 1909 Darwin celebration thus represents a significant watershed in the history of modern biology that allows historians to assess the status of evolution prior to the advent of the chromosome theory of genetics. (shrink)

Joseph Agassi develops a humanist world view in his last single-authored book through confronting the challenges facing the humanist world view. The three challenges that Agassi confronts are: 1. how do we rationally choose ways of life, including the life of rationality? 2. is humanity worthwhile? 3. how can we improve liberal democracy in our fractured societies where extremists seek to gain control?

Despite the emergence of new forms of feminist empiricism, there continues to be resistance to the idea that feminist political commitment can be integral to hypothesis testing in science when that process adheres strictly to empiricist norms and is grounded in a realist conception of objectivity. I explore the virtues of such feminist empiricism, arguing that the resistance is, in large part, due to the lingering effects of positivism.

The psychological orientation treats semantics as a matter of idealized computation over symbolic structures, and semantic relations like denotation as relations between linguistic expressions and these structures. I argue that results similar to Gödel's incompleteness theorems and Tarski's theorem on truth create foundational difficulties for this view of semantics.