Neil Tennant and Joseph Salerno have recently attempted to rigorously formalize Michael Dummett's argument for logical revision. Surprisingly, both conclude that Dummett commits elementary logical errors, and hence fails to offer an argument that is even prima facie valid. After explicating the arguments Salerno and Tennant attribute to Dummett, I show how broader attention to Dummett's writings on the theory of meaning allows one to discern, and formalize, a valid argument for logical revision. Then, after correctly providing a rigorous statement (...) of the argument, I am able to delineate four possible anti-Dummettian responses. Following recent work by Stewart Shapiro and Crispin Wright, I conclude that progress in the anti-realist's dialectic requires greater clarity about the key modal notions used in Dummett's proof. (shrink)

I discuss a problem for modal realism raised by John Divers and others. I argue that the problem is real enough but that Divers’ “advanced modalising” solution is inadquate. The problem can only be solved by 1) holding that modal realism is only contingently true, 2) embracing a kind of Meinongianism about ontological commitment, or 3) abandoning the project of “analysing modality”.

Dan Marshall and Josh Parsons note, correctly. that the property of being either a cube or accompanied by a cube is incorrectly classified as intrinsic under the definition we have given unless it turns out to be disjunctive. Whether it is disjunctive, under the definition we gave, turns on certain judgements of the relative naturalness of properties. They doubt the judgements of relative naturalness that would classify their property as disjunctive. We disagree. They also suggest that the whole (...) idea of judging relative naturalness is a dubious business. We reply that, like them or not, such judgements cannot easily be avoided. (shrink)

The following quotation, from Frank Jackson, is the beginning of a typical exposition of the debate between those metaphysicians who believe in temporal parts, and those who do not: The dispute between three-dimensionalism and four-dimensionalism, or more precisely, that part of the dispute we will be concerned with, concerns what persistence, and correllatively, what change, comes to. Three-dimensionalism holds that an object exists at a time by being wholly present at that time, and, accordingly, that it persists if it is (...) wholly present at more than one time. For short, it persists by enduring. Four-dimensionalism holds that an object exists at a time by having a temporal part at that time, and it persists if it has distinct temporal parts at more than one time. For short, it persists by perduring. In the light of these comments, some readers will perhaps find the question that forms the title of this paper a little puzzling. They may have learned to use the terms ‘fourdimensionalism’ ‘perdurantism’ and ‘belief in temporal parts’ interchangeably; or perhaps even to define one in terms of the other. Such a usage, however, is inapposite. We might imagine a Flatland-like world of two spatial dimensions and one temporal, whose philosophers are divided between a theory of persistence on which they persist by having temporal parts, and a theory on which they persist by being wholly located in each of several times. This is just the same issue we face, but at least the label ‘four-dimensionalism’ seems inapposite: the four-dimensionalist Flatlanders believe in only three dimensions! (shrink)

In his two recent books on ontology, Universals: an Opinionated Introduction, and A World of States of Affairs, David Armstrong gives a new argument against nominalism. That argument seems, on the face of it, to be similar to another argument that he used much earlier against Rylean behaviourism: the Truthmaker Argument, stemming from a certain plausible premise, the Truthmaker Principle. Other authors have traced the history of the truthmaker principle, its appearance in the work of Aristotle [10], Bradley [16], and (...) even Husserl [15]. But that is not my task — in this paper I argue that Armstrong’s new argument is not logically analogous to the old, and, in particular, that it is quite possible to be a thoroughgoing nominalist, and hold a truthmaker principle. (shrink)

ABSTRACT This paper proposes a novel answer to the Special Composition Question. In some respects it agrees with brutalism about composition; in others with universalism. The main novel feature of this answer is the insight I think it gives into what the debate over the Special Composition Question is about.

I want to join Dummett in saying that the reality of the past (and, by analogy, the reality of the future) is an issue of realism versus anti-realism: (Dummett 1969) If you affirm the reality of the past, you are a realist about the past. If you deny the reality of the past, you are an anti-realist about the past. (And likewise, in each case, for the future). It makes sense to think of these issues by analogy with realism about (...) the external world, unobservable objects, mathematical objects, universals, and so on. These are all properly described as ontological issues. (shrink)

I argue that Colin Cheyne and Charles Pigden's recent attempt to find truthmakers for negative truths fails. Though Cheyne and Pigden are correct in their treatment of some of the truths they set out to find truthmakers for (such as 'There is no hippopotamus in S223' and 'Theatetus is not flying') they over-generalize when they apply the same treatment to 'There are no unicorns'. In my view, this difficulty is ineliminable: not every truth has a truthmaker.

Cognitivism about imperatives is the thesis that sentences in the imperative mood are truth-apt: have truth values and truth conditions. This allows cognitivists to give a simple and powerful account of consequence relations between imperatives. I argue that this account of imperative consequence has counterexamples that cast doubt on cognitivism itself.

An argument is usually said to be valid iff it is truth-preserving—iff it cannot be that all its premises are true and its conclusion false. But imperatives (it is normally thought) are not truth-apt. They are not in the business of saying how the world is, and therefore cannot either succeed or fail in doing so. To solve this problem, we need to find a new criterion of validity, and I aim to propose such a criterion.

We argue that Maclaurin and Dyke's recent critique of non-naturalistic metaphysics suffers from difficulties analogous to those that caused trouble for earlier positivist critiques of metaphysics. Maclaurin and Dyke say that a theory is naturalistic iff it has observable consequences. Depending on the details of this criterion, either no theory counts as naturalistic or every theory does.

The debate between A-theory and B-theory in the philosophy of time is a persistent one. It is not always clear, however, what the terms of this debate are. A-theorists are often lumped with a miscellaneous collection of heterodox doctrines: the view that only the present exists, that time flows relentlessly, or that presentness is a property (Williams 1996); that time passes, tense is unanalysable, or that earlier than and later than are defined in terms of pastness, presentness, and futurity (Bigelow (...) 1991); or that events or facts (as opposed to language) are “tensed” (Mellor 1993). B-theorists then argue that the A-theory is incoherent, using variants on J.M.E. McTaggart’s argument for the unreality of time (McTaggart 1927, ch. 33). (shrink)

This paper presents an argument that the way we experience time is more consistent with our being instantaneous objects than with our being temporally extended throughout our entire lifetimes. By argument to the best explanation therefore, experiencing subjects persons are stages, rather than worms.

This intuition may be contrasted with the incompatible intuitions that might support, say, average utilitarianism. According to average utilitarianism we should bring about that outcome which has the highest average utility. That someone would have a higher than average level of utility is, therefore, ceteris paribus a reason to act so that that person exists. Because of this, the basic intuition is a reason for rejecting average utilitarianism.

This seems to me to be a metaphysically significant feature of CEM. If CEM is correct — if all its theorems are true, then metaphysicians have a choice to make in how we understand the mereological nature of the world. We may think of the mereological relation either as a relation of part to whole, or as a relation of overlap; for if we give a metaphysical theory about one, we thereby give a metaphysical theory about the other. We may (...) choose which we think of as more metaphysically fundamental, for the they are interdefinable. However, if CEM is not correct, then perhaps we do not have this choice. Perhaps part-whole cannot be defined in terms of overlap; in which case we must choose part-whole as the metaphysical fundamental mereological relation (if any relation is). (shrink)

In this paper, I consider whether tenses, temporal indexicals, and other indexicals are contextually dependent on the context of assessment (or a-contextual), rather than, as is usually thought, contextually dependent on the context of utterance (u-contextual). I begin by contrasting two possible linguistic norms, governing our use of context sensitive expressions, especially tenses and temporal indexicals (??2 and 3), and argue that one of these norms would make those expressions u-contextual, while the other would make them a-contextual (?4). I then (...) ask which of these two norms are followed by English speakers (?5). Finally, I argue that the existence of a-contextuality does not in any sense entail ?relativism? about truth (?6). (shrink)

ABSTRACTI offer a simple‐minded analysis of presupposition in which if a sentence has a presupposition, then both that sentence and its negation logically entail the presupposition; and in which sentence with failed presuppositions are neither true nor false. This account naturally generates an analysis of what it takes to disagree and what it takes to be at fault in a disagreement. A simple generalization gives rise to the possibility of disagreements in which no party is at fault, as is required (...) by leading theories on predicates of taste. (shrink)

Normally this is not how we think material objects work. I, for example, am a material object that is located in multiple places: this place to my left where my left arm is, and this, distinct, place to my right, where my right arm is. But I am only partially located in each place. My left arm is a part of me that fills exactly the place to my left, and my right arm is a distinct part of me that (...) fills exactly the place to my right. I am located in multiple places by virtue of having distinct parts in those places. So entension is not happening to me — I do not entend. (shrink)

This paper considers how to put together two popular ideas in the philosophy of time: detenserism and perdurantism (the view that objects persist through time by having temporal parts. On the most obvious way of doing this, certain problems arise. I argue that to deal with these problems we need a tool that is unfamiliar to most detensers and perdurantists - the distinction between sortal and non-sortal predicates.

It’s well known that one way to cure a hangover is by a “hair of the dog” — another alcoholic drink. The drawback of this method is that, so it would appear, it cannot be used to completely cure a hangover, since the cure simply induces a further hangover at a later time, which must in turn either be cured or suffered through.

If the former is the case, let us say that anti-reductionism about relational facts is true; if the latter, that reductionism about relational facts is true. Let us say that a fact is relational if it makes true some relational proposition (a proposition that asserts that a relation holds between some objects1), that it is irreducibly relational if, in addition, it does not make true any nonrelational propositions, and that it is monadic if it is not irreducibly relational (if it (...) makes true some proposition that does not assert that a relation holds between some objects). (shrink)

In my (2004), I argued that it is possible to drink any finite amount of alcohol without ever suffering a hangover by completing a certain kind of supertask. Assume that a drink causes drunkenness to ensue immediately and to last for a period proportional to the quantity of alcohol consumed; that a hangover begins immediately at the time the drunkenness ends and lasts for the same length of time as the drunkenness; and that at any time during which you are (...) drunk you do not suffer any hangover you might have at that time. Starting at a time at which you are not drunk and not hung over, drink a half pint of beer. Wait until you are just about to get a hangover (30 minutes, say), and then drink a quarter pint. Wait until you are just about to get a hangover again, and then drink an eighth, and so on.... After an hour you have drunk a pint, and you do not have a hangover. Every hangover you incurred happened within the hour you spent drinking; but you were drunk that whole time, so you didn’t suffer the hangovers. It seems that the old drunkard’s method of a “hair of the dog” can be effective in completely avoiding a hangover. (shrink)

This paper discusses “inclusionism” in the context of David Lewis’s modal realism (and in the context of parasitic accounts of modality such as John Divers’s agnosticism about possible worlds). This is the doctrine that everything is a world. I argue that this doctrine would be beneficial to Divers-style agnosticism; that it suggests a reconfiguration of the concept of actuality in modal realism; and finally that it suffers from an as-yet unsolved difficulty, the problem of the unmarried husbands. This problem also (...) shows that Stephen Yablo’s analysis of “intrinsic” is inadequate. (shrink)

Let us call “tense logic” the programme of explaining tense in natural languages by means of a model theory similar in structure to possible worlds semantics for modality. This programme would make the following claims.

Here is a puzzle from the Stoic, Chrysippus: There was once a man called Dion, who was unfortunate enough to have his foot annihilated. Thereafter, he was known as Theon. Theon is identical to what was left over after Dion’s foot was removed. That is, Theon is that part of Dion that does not include his foot. If all this is true, then Theon is a proper part of Dion. That is, he is a part of Dion, but not identical (...) to Dion. But if that’s right, then, surprisingly, Dion didn’t survive the loss of his foot. (shrink)

This paper discusses the handicapped child case and some other variants of Derek Parfit's non-identityproblem (Parfit, 1984) The case is widely held to show that there is harmless wrongdoing, and that amoral system which tries to reduce wrongdoing directly to harm (``person-affecting morality'')is inadequate.I show that the argument for this does not depend (as some have implied it does) on Kripkean necessity of origin. I distinguish the case from other variants (``wrongful life cases'') of the non-identityproblem which do not bear (...) directly on person-affecting morality as I understand it. And finally, I describe a respect in which the handicapped child case is puzzling and counter-intuitive, even on the supposition that it is a case of harmless wrongdoing. I conclude that the case is ``hard'': it will take more than the rejection of person-affecting morality to remove its puzzling character. (shrink)

Paper begins: I have two gloves, a left glove and a right glove. I can fit the left glove onto my left hand, but not the right glove. Why? Because the right glove is the wrong shape to go on my left hand. So the two gloves are different shapes….

An imperative conditional is a conditional in the imperative mood (by analogy with “indicative conditional”, “subjunctive conditional”). What, in general, is the meaning and the illocutionary effect of an imperative conditional? I survey four answers: the answer that imperative conditionals are commands to the effect that an indicative conditional be true; two versions of the answer that imperative conditionals express irreducibly conditional commands; and finally, the answer that imperative conditionals express a kind of hybrid speech act between command and assertion.

Truthmaker theorists typically claim not only that all truths have truthmakers (Truthmaker Maximalism), but also that there is some enlightening metaphysical theory to be given of the nature of those truthmakers (e.g. that they are Armstrongian states of affairs, or tropes, or concrete individuals). Call this latter thesis the "Material Theory Thesis" (it is the thesis that there is some true material theory of truthmakers). I argue that the Material Theory Thesis is inconsistent with Truthmaker Maximalism.

It’s now commonplace — since Korsgaard (1996) — in ethical theory to distinguish between two distinctions: on the one hand, the distinction between value an object has in virtue of its intrinsic properties vs. the value it has in virtue of all its properties, intrinsic or extrinsic; and on the other hand, the distinction between the value has an object as an end, vs. the value it has as a means to something else. I’ll call the former distinction the distinction (...) between intrinsic and nonintrinsic value; the latter is between value as-an-end and instrumental value. (shrink)

This paper began life as a short section of a more general paper about non-classical mereologies. In that paper I had a mereological theory that I wanted to show could be applied to all sorts of different metaphysical positions — notably, to those positions that believe in mereological vagueness in re — in “vague individuals”. To do that I felt I first had to dispatch the leading rival theory of vague individuals, which is due to Peter van Inwa-gen, and holds (...) that the part-whole relation admits of degrees. It seemed to me that this theory had a serious technical problem, or at best a serious gap. I sat down to write a paragraph or two highlighting the gap, preferably showing that it couldn’t be filled. This paper is the result. (shrink)

The problem of imperative consequence consists in the fact that theses (i) through (iii) are inconsistent; but yet all three are attractive (for the reasons sketched above). A solution to the problem consists in the denial of one of the three theses; I describe solutions as belonging to type 1, type 2, or type 3, depending on which thesis they deny. For the purposes of this paper, I would like to focus on a certain variety of type 3 solution – (...) a solution that offers a revised criterion of validity of a particular kind. (shrink)

Analytic philosophers usually think about modality in terms of possible worlds. According to the possible worlds framework, a proposition is necessary if it is true according to all possible worlds; it is possible if it is true according to some possible world. There are as many possible worlds as there are ways the actual world might be. Only one world is actual.

This logic has a standard one-dimensional possible worlds semantics with an accessibility relation (I will call this, for short, the accessibility semantics for KDDc4, contrasting with the preposcription semantics given in “Command and consequence”). In the accessibility semantics, the semantic value of a sentence is a world (rather than a pair of worlds).

Book Information Real Metaphysics. Real Metaphysics Hallvard Lillehammer and Gonzalo Rodriguez-Pereyra , eds., London : Routledge , 2003 , VIII + 248 , £65 ( cloth ), £19.99 ( paper ) Edited by Hallvard Lillehammer; and Gonzalo Rodriguez-Pereyra . Routledge. London. Pp. VIII + 248. £65 (cloth:), £19.99 (paper:).

Paper begins: Chapter 4 of Hud Hudson’s stimulating book The metaphysics of hyperspace contains an discussion of the notion of location in a container spacetime. Hudson uses this idea to define a number of what we might call modes of extension or ways of being extended. A pertended object is what most people think of as a typical extended object — it is made up of spatial parts, one part for each region the object pervades. An entended object is an (...) extended simple (or a complex object made up of extended simples). Elsewhere, I’ve argued that entended objects are conceptually possible; that nothing about the concept of “extended” rules out entention. (More about how this argument works below). Hudson thinks that I did not go far enough. Besides pertended and entended objects, he also sees conceptual room for what he calls spanners and multiply located objects. These last two ways of being extended are even more exotic than extended simples. …. (shrink)

“The truth,” Quine says, “is that you can bathe in the same river twice, but not in the same river stage. You can bathe in two river stages which are stages of the same river, and this is what constitutes bathing in the same river twice. A river is a process through time, and the river stages are its momentary parts.” (Quine 1953, p. 65) Quine’s view is four-dimensionalism, and that is what Theodore Sider’s book is about. In Sider’s usage, (...) four-dimensionalism is the view that, necessarily, anything in space and time has a distinct temporal part, or stage, corresponding to each time at which it exists (p. 59). (shrink)

This book is a survey, fortified by original material, of metaphysical theories of modality set in terms of possible worlds. Those theories include what Divers calls “genuine realism”, or “GR” — this is David Lewis’s “genuine modal realism” — and what Divers calls “actualist realism”, or “AR” — this seems to be the same as what Lewis called “ersatz modal realism”, which has also become widely know as “ersatzism”. Two important kinds of theory are not included: those that treat modality (...) by means not involving possible worlds at all (for example, modalism, various kind of non-cognitivism, and Quinean eliminativism about modality); and those that, while treating modality by talking about possible worlds, go on to deny that there are any possible worlds in one way or another (for example, Rosen’s fictionalism, and Divers’ own agnosticism about possible worlds). These get a short discussion towards the end of the introductory part of the book (sections 2.4–2.6), and Divers is planning to write a companion volume covering them. (shrink)

Dan Marshall and Josh Parsons note, correctly. that the property of being either a cube or accompanied by a cube is incorrectly classified as intrinsic under the definition we have given unless it turns out to be disjunctive. Whether it is disjunctive, under the definition we gave, turns on certain judgements of the relative naturalness of properties. They doubt the judgements of relative naturalness that would classify their property as disjunctive. We disagree. They also suggest that the whole (...) idea of judging relative naturalness is a dubious business. We reply that, like them or not, such judgements cannot easily be avoided. (shrink)

That AI will have a major impact on society is no longer in question. Current debate turns instead on how far this impact will be positive or negative, for whom, in which ways, in which places, and on what timescale. In order to frame these questions in a more substantive way, in this prolegomena we introduce what we consider the four core opportunities for society offered by the use of AI, four associated risks which could emerge from its overuse or (...) misuse, and the opportunity costs associated with its under use. We then offer a high-level view of the emerging advantages for organisations of taking an ethical approach to developing and deploying AI. Finally, we introduce a set of five principles which should guide the development and deployment of AI technologies. The development of laws, policies and best practices for seizing the opportunities and minimizing the risks posed by AI technologies would benefit from building on ethical frameworks such as the one offered here. (shrink)

Nevertheless, any competent speaker will know what it means. What explains our ability to understand sentences we have never before encountered? One natural hypothesis is that those novel sentences are built up out of familiar parts, put together in familiar ways. This hypothesis requires the backing hypothesis that English has a compositional semantic theory.

In a series of papers, Donald Davidson :3–17, 1984, The philosophical grounds of rationality, 1986, Midwest Stud Philos 16:1–12, 1991) developed a powerful argument against the claim that linguistic conventions provide any explanatory purchase on an account of linguistic meaning and communication. This argument, as I shall develop it, turns on cases of what I call lexical innovation: cases in which a speaker uses a sentence containing a novel expression-meaning pair, but nevertheless successfully communicates her intended meaning to her audience. (...) I will argue that cases of lexical innovation motivate a dynamic conception of linguistic conventions according to which background linguistic conventions may be rapidly expanded to incorporate new word meanings or shifted to revise the meanings of words already in circulation. I argue that this dynamic account of conventions both resolves the problem raised by cases of lexical innovation and that it does so in a way that is preferable to those who—like Davidson—deny important explanatory roles for linguistic conventions. (shrink)

Initiatives relying on artificial intelligence (AI) to deliver socially beneficial outcomes—AI for social good (AI4SG)—are on the rise. However, existing attempts to understand and foster AI4SG initiatives have so far been limited by the lack of normative analyses and a shortage of empirical evidence. In this Perspective, we address these limitations by providing a definition of AI4SG and by advocating the use of the United Nations’ Sustainable Development Goals (SDGs) as a benchmark for tracing the scope and spread of AI4SG. (...) We introduce a database of AI4SG projects gathered using this benchmark, and discuss several key insights, including the extent to which different SDGs are being addressed. This analysis makes possible the identification of pressing problems that, if left unaddressed, risk hampering the effectiveness of AI4SG initiatives. (shrink)