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.     

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.

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.

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.

Concepts and Recipes

If concepts are explicated as abstract procedures, then we can easily show that each empirical concept is a not an effective procedure. Some, but not all empirical concepts are shown to be of a special kind: they cannot in principle guarantee that the object they identify satisfies the intended conditions.

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.

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.

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.

Two-dimensionalism and the “Knowing Which” Requirement

Two-dimensional semantics aims to eliminate the puzzle of necessary a posteriori and contingent a priori truths. Recently many argue that even assuming two-dimensional semantics we are left with the puzzle of necessary and a posteriori propositions. Stephen Yablo (Pacific Philosophical Quarterly, 81, 98–122, 2000) and Penelope Mackie (Analysis, 62(3), 225–236, 2002) argue that a plausible sense of “knowing which” lets us know the object of such a proposition, and yet its necessity is “hidden” and thus a posteriori. This paper answers this objection; I argue that given two-dimensional semantics you cannot know a necessary proposition without knowing that it is true.

Anomaly detection in a mobile communication network

Mobile communication networks produce massive amounts of data which may be useful in identifying the location of an emergency situation and the area it affects. We propose a one pass clustering algorithm for quickly identifying anomalous data points. We evaluate this algorithm’s ability to detect outliers in a data set and describe how such an algorithm may be used as a component of an emergency response management system.

Equality of Opportunity and Personal Identity

One of the central theses of egalitarian liberals in the domain of distributive justice is that talented individuals should not be allowed to keep their entire market-income even if it flows solely from their greater abilities. This claim is usually supported by one of several arguments or some mixture of them, but in the present paper, I want to concentrate on the version that invokes equality of opportunity as its starting point. Namely, it is claimed that every human being should enjoy an equal starting point in the life-race but that this is not secured insofar as some have greater natural talents than others. Therefore, egalitarians hold that results that arise from such an unfair situation are unjust and should be corrected by a redistributive taxation. I want to criticize this argument by hoping to show that it presupposes an untenable view about identity of persons.

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.

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.

No Lacuna and No Vicious Regress: A Reply to Le Poidevin

In his “Space, supervenience and substantivalism”, Le Poidevin proposes a substantivalism in which space is discrete, implying that there are unmediated spatial relations between neighboring primitive points. This proposition is motivated by his concern that relationism suffers from an explanatory lacuna and that substantivalism gives rise to a vicious regress. Le Poidevin implicitly requires that the relationist be committed to the “only x and y” principle regarding spatial relations. It is not obvious that the relationist is committed to this principle in such a context. An additional motivation for Le Poidevin's argument, that space should be considered to be discrete, is that he believes that substantivalists are committed to a vicious regress. I show that the regress is in fact not of the vicious variety. These two main arguments show that Le Poidevin's suggestion that we drop the density postulate for space is unnecessary.

Some Remarks on “Language-Created Entities”

Some entities, such as fictional characters, propositions, properties, events and numbers are prima facie promising candidates for owing their existence to our linguistic and conceptual practices. However, it is notoriously hard to pin down just what sets such allegedly “language-created” entities apart from ordinary entities. The present paper considers some of the features that are supposed to distinguish between entities of the two kinds and argues that, on an independently plausible account of what it takes to individuate objects, the criteria let in more than friends of the strategy might be happy with.

Conversational Implicatures and Cancellability

In this paper I argue against a criticism by Matthew Weiner to Grice’s thesis that cancellability is a necessary condition for conversational implicature. I argue that the purported counterexamples fail because the supposed failed cancellation in the cases Weiner presents is not meant as a cancellation but as a reinforcement of the implicature. I moreover point out that there are special situations in which the supposed cancellation may really work as a cancellation.

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.

The Mathematical Pull of Temptation Revisited

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

On the Coherence of Inversion

In this paper, I shall evaluate a strategy recently used to try to demonstrate the impossibility of behaviorally undetectable spectrum inversion. After showing that the impossibility proof proves too much, I shall identify where it goes wrong. In turn, I shall explain why someone attracted to functionalist and representationalist assumptions might rightly remain agnostic about the possibility of inversion.

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.