True Antecedents

In this note I discuss what seems to be a new kind of counterexample to Lewis’s account of counterfactuals. A coin is to be tossed twice. I bet on ‘Two heads’, and I win. Common sense says that (1) is false. But Lewis’s theory says that it is true. (1) If at least one head had come up, I would have won.

Closure,Defeasibility and Conclusive Reasons

It is argued, on the basis of new counterexamples, that neither knowledge nor epistemic justification (or “epistemic rationality”) can reasonably be thought to be closed under logical implication. The argument includes an attempt to reconcile the fundamental intuitions of the opposing parties in the debate.

Is Believing at Will ‘Conceptually Impossible’?

In this paper I discuss the claim that believing at will is ‘conceptually impossible’ or, to use a formulation encountered in the debate, “that nothing could be a belief and be willed directly”. I argue that such a claim is only plausible if directed against the claim that believing itself is an action-type. However, in the debate, the claim has been univocally directed against the position that forming a belief is an action-type. I argue that the many arguments offered in favor of the ‘conceptual impossibility’ of performing such actions fail without exception. If we are to argue against doxastic voluntarism we are better off by resorting to more modest means.

A Warranted-assertability Defense of a Moorean Response to Skepticism

According to a Moorean response to skepticism, the standards for knowledge are invariantly comparatively low, and we can know across contexts all that we ordinarily take ourselves to know. It is incumbent upon the Moorean to defend his position by explaining how, in contexts in which S seems to lack knowledge, S can nevertheless have knowledge. The explanation proposed here relies on a warranted-assertability maneuver: Because we are warranted in asserting that S doesn’t know that p, it can seem that S does in fact lack that piece of knowledge. Moreover, this warranted-assertability maneuver is unique and better than similar maneuvers because it makes use of H. P. Grice’s general conversational rule of Quantity—“Do not make your contribution more informative than is required”—in explaining why we are warranted in asserting that S doesn’t know that p.

Thought Structure, Belief Content, and Possession Conditions

According to Peacocke, concepts are individuated by their possession conditions, which are specified in terms of conditions in which certain propositions containing those concepts are believed. In support, Peacocke tries to explain what it is for a thought to have a structure and what it is for a belief to have a propositional content. I show that the possession condition theory cannot answer such fundamental questions. Peacocke’s theory founders because concepts are metaphysically fundamental. They individuate the propositions and thoughts containing them, which in turn individuate the propositional attitudes that are relations to those propositions or thoughts.

Baker on the Psychological Account of Personal Identity

Lynne Rudder Baker’s Constitution View of human persons has come under much recent scrutiny. Baker argues that each human person is constituted by, but not identical to, a human animal. Much of the critical discussion of Baker’s Constitution View has focused upon this aspect of her account. Less has been said about the positive diachronic account of personal identity offered by Baker. Baker argues that it is sameness of what she labels ‘first-person perspective’ that is essential to understanding personal identity over time. Baker claims that her account avoids the commitment to indeterminacy of personal identity entailed by the psychological account. Further, the psychological account, but not her account, is plagued by what Baker labels the ‘duplication problem’. In the end, I argue that neither of these considerations forces us to renounce the psychological account and adopt Baker’s favored account.

Meta-ethics and Justification

The author takes up three metaphysical conceptions of morality — realism, projectivism, constructivism — and the account of justification or reason that makes these pictures possible. It is argued that the right meta-ethical conception should be the one that entails the most plausible conception of reason-giving, rather than by any other consideration. Realism and projectivism, when understood in ways consistent with their fundamental commitments, generate unsatisfactory models of justification; constructivism alone does not. The author also argues for a particular interpretation of how “objective moral obligation” is to be understood within constructivism.

Computational Construction as a Means to Coordinate Representations of Infinity

In this paper, we describe a design experiment aimed at helping students to explore and develop concepts of infinite processes and objects. Our approach is based on the design and development of a computational microworld, which afforded students the means to construct a range of representational models (symbolic, visual and numeric) of infinity-related objects (infinite sequences, in particular). We present episodes based on four students’ activities, seeking to illustrate how the available tools mediated students’ understandings of the infinite in rich ways, allowing them to discriminate subtle process-oriented features of infinite processes. We claim that the microworld supported students in the coordination of hitherto unconnected or conflicting intuitions concerning infinity, based on a constructive articulation of different representational forms we name as ‘representational moderation’.

Can Concepts Ground Apriori Knowledge? Peacocke’s Referential Turn and its Challenges

The paper is a critical examination of Peacocke’s pioneering work on concepts as grounding the possibility of a priori knowledge. It focuses upon his more recent turn to reference and referential domain, and the two enlargements of the purely conceptual bases for apriority, namely appeal to conceptions and to direct referential sensitivity. I argue that the two are needed, but they produce more problem for the strategy as a whole than they solve. I conclude by suggesting that they point to a possible Benacerraf-like dilemma for conceptualist accounts of armchair knowledge: if concepts are akin to representational contents and/or conceptions, they certainly do not metaphysically determine anything. At best, they fallibly guide our inquiry and get corrected almost by each new important discovery about the nature of their referents. If what is meant by “concept” is a Fregean, objectively correct and metaphysically potent entity, there is little doubt in its power to determine its referent(s), but there is a huge epistemic problem of how we grasp such Platonic concepts. Peacocke’s early metaphysics of concept, which offered beginnings of an answer, is put in jeopardy by the new referential turn, and his valiant attempts to pass between the multiple horns of this dilemma seem to face a lot of difficulties.

Evolving networks for social optima in the “weakest link game”

Previous models have applied evolving networks based on node-level “copy and rewire” rules to simple two player games (e.g. the Prisoner’s Dilemma). It was found that such models tended to evolve toward socially optimal behavior. Here we apply a similar technique to a more tricky co-ordination game (the weakest link game) requiring interactions from several players (nodes) that may play several strategies. We define a variant of the game with several equilibria—each offering increasing social benefit. We found that the evolving network functions to select and spread more optimal equilibria while resisting invasion by lower ones. Hence the network acts as a kind of “social ratchet” selecting for increasing social benefit. Such networks have applications in peer-to-peer computing and may have implications for understanding social systems.

Margins for Error and Sensitivity: What Nozick Might Have Said

Timothy Williamson has provided damaging counterexamples to Robert Nozick’s sensitivity principle. The examples are based on Williamson’s anti-luminosity arguments, and they show how knowledge requires a margin for error that appears to be incompatible with sensitivity. I explain how Nozick can rescue sensitivity from Williamson’s counterexamples by appeal to a specific conception of the methods by which an agent forms a belief. I also defend the proposed conception of methods against Williamson’s criticisms.

A Critique of Armstrong’s Truthmaking Account of Possibility

In this paper I argue against Armstrong’s recent truthmaking account of possibility. I show that the truthmaking account presupposes modality in a number of different ways, and consequently that it is incapable of underwriting a genuine reduction of modality. I also argue that Armstrong’s account faces serious difficulties irrespective of the question of reduction; in particular, I argue that his Entailment and Possibility Principles are both false.

The Mathematical Pull of Temptation Revisited

In this paper, we defend and extend a (simple) mathematical model of akrasia.

If this is our mathematics, what are our stories?

This paper sets out to examine how narrative modes of thinking play a part in the claiming of mathematical territories as our own, in navigating mathematical landscapes and in conversing with the mathematical beings that inhabit them. We begin by exploring what constitutes the narrative mode, drawing principally on four characteristics identified by Bruner and considering how these characteristics manifest themselves in the activities of mathematicians. Using these characteristics, we then analyse a number of examples from our work with expressive technologies; we seek to identify the narrative in the interactions of the learners with different computational microworlds. By reflecting on the learners’ stories, we highlight how particular features, common across the microworlds—motion, colour, sound and the like—provided the basis for both the physical and psychological grounding of the behaviour of the mathematically constrained computational objects. In this way, students constructed and used narratives that involved situating mathematical activities in familiar contexts, whilst simultaneously expressing these activities in ways which—at least potentially—transcend the particularities of the story told.

Understanding the Small Object Argument

The small object argument is a transfinite construction which, starting from a set of maps in a category, generates a weak factorisation system on that category. As useful as it is, the small object argument has some problematic aspects: it possesses no universal property; it does not converge; and it does not seem to be related to other transfinite constructions occurring in categorical algebra. In this paper, we give an “algebraic” refinement of the small object argument, cast in terms of Grandis and Tholen’s natural weak factorisation systems, which rectifies each of these three deficiencies.

Some Advantages of One Form of Argument for the Maximin Principle

This paper presents a non-consequentialist defense of Rawls’s general conception of justice requiring that primary social goods be distributed so that the least share is as great as possible. It suggests that a defense of this idea can be offered within a Rossian framework of prima facie duties. The prima facie duty not to harm constrains people from supporting social institutions which do not leave their fellows with goods and resources above a certain threshold. The paper argues that societies in accord with the Rawlsian general conception come closest to meeting this requirement. This way of arguing for the conception enables the defenders of the theory to elude standard objections offered by utilitarians, libertarians, and even other egalitarians.

Conceptualism and the Problem of Illusory Experience

According to the conceptualist view in the philosophy of perception, we possess concepts for all the objects, properties, and relations which feature in our experiences. Richard Heck has recently argued that the phenomenon of illusory experience provides us with conclusive reasons to reject this view. In this paper, I examine Heck’s argument, I explain why I think that Bill Brewer’s conceptualist response to it is ineffective, and I then outline an alternative conceptualist response which I myself endorse. My argument turns on the fact that both Heck, in constructing his objection to conceptualism, and Brewer, in responding to it, miss a crucial distinction between perceptual demonstrative concepts of objects, on the one hand, and perceptual demonstrative concepts of properties, on the other.

Sperm, Eggs and Hunks: Biological Origins and Identity

In several publications Graeme Forbes has developed and defended one of the strongest arguments for essentialism about biological origins. I attempt to show that there are deep, as yet unrecognized, problems with this argument. The problems with Forbes’s argument suggest that a range of other arguments for various forms of origin essentialism are also likely to be flawed, and that we should abandon the seemingly plausible general metaphysical thesis that concrete entities that share all intrinsic properties are identical.

Transglobal Evidentialism-Reliabilism

We propose an approach to epistemic justification that incorporates elements of both reliabilism and evidentialism, while also transforming these elements in significant ways. After briefly describing and motivating the non-standard version of reliabilism that Henderson and Horgan call “transglobal” reliabilism, we harness some of Henderson and Horgan’s conceptual machinery to provide a non-reliabilist account of propositional justification (i.e., evidential support). We then invoke this account, together with the notion of a transglobally reliable belief-forming process, to give an account of doxastic justification.