The interpretation of quantum mechanics is an area of increasing interest to many working physicists. In particular, interest has come from those involved in quantum computing and information theory, as there has always been a strong foundational element in this field. This paper introduces one interpretation of quantum mechanics, a modern ‘many-worlds’ theory, from the perspective of quantum computation. Reasons for seeking to interpret quantum mechanics are discussed, then the specific ‘neo-Everettian’ theory is introduced and its claim as the best (...) available interpretation defended. The main objections to the interpretation, including the so-called “problem of probability” are shown to fail. The local nature of the interpretation is demonstrated, and the implications of this both for the interpretation and for quantum mechanics more generally are discussed. Finally, the consequences of the theory for quantum computation are investigated, and common objections to using many worlds to describe quantum computing are answered. We find that using this particular many-worlds theory as a physical foundation for quantum computation gives several distinct advantages over other interpretations, and over not interpreting quantum theory at all. (shrink)

Is the ability to speak a language an acquired skill? Leading proponents of the generative approach to human language—notably Chomsky (2000) and Pinker (2003)—have argued that the thesis that language capacities are skills is hopelessly confused and at odds with a range of empirical evidence, which suggests that human language capacities are grounded in a biologically inherited set of language instincts or a Universal Grammar (UG). In this paper, we argue that resistance to the claim that human language capacities are (...) skills has been fostered by naïve and implausible conceptions of the nature of skilled action. Correcting these misconceptions about the nature of skilled action breathes new life into the old idea that human language competences are particular kinds of skills and does so in a way that is fully consistent with appeals to the central importance of UG, broadly construed. More generally, we argue that by taking human language capacities to be skills, we capture what is right about the generative program while at the same time avoiding its most serious pitfalls. (shrink)

There has been very little discussion of the appropriate principles to govern a modal logic of plurals. What debate there has been has accepted a principle I call (Necinc); informally if this is one of those then, necessarily: this is one of those. On this basis Williamson has criticised the Boolosian plural interpretation of monadic second-order logic. I argue against (Necinc), noting that it isn't a theorem of any logic resulting from adding modal axioms to the plural logic PFO+, and (...) showing that the most obvious formal argument in its favour is question begging. I go on to discuss the behaviour of natural language plurals, motivating a case against (Necinc) by developing a case that natural language plural terms are not de jure rigid designators. The paper concludes by developing a model theory for modal PFO-f which does not validate (Necinc). An Appendix discusses (Necinc) in relation to counterpart theory. Of course, it would be a mistake to think that the rules for "multiple pointing" follow automatically from the rules for pointing proper. Max Black—The Elusiveness of Sets In some influential articles during the 1980s George Boolos proposed an interpretation of monadic second-order logic in terms of plural quantification [4, 5]. One objection to this proposal, pressed by Williamson [22, 456-7], focuses on the modal behaviour of plural variables, arguing that the proposed interpretation yields the wrong results in respect of the modal status of atomic predications. In the present paper I will present this objection and argue against it. In the course of developing the argument, I will have cause to consider the under-investigated question of how a logic for plurals should be extended to incorporate modal operators. (shrink)

Robert Nozick's experience machine thought experiment is often considered a decisive refutation of hedonism. I argue that the conclusions we draw from Nozick's thought experiment ought to be informed by considerations concerning the operation of our intuitions about value. First, I argue that, in order to show that practical hedonistic reasons are not causing our negative reaction to the experience machine, we must not merely stipulate their irrelevance (since our intuitions are not always responsive to stipulation) but fill in the (...) concrete details that would make them irrelevant. If we do this, we may see our feelings about the experience machine becoming less negative. Second, I argue that, even if our feelings about the experience machine do not perfectly track hedonistic reasons, there are various reasons to doubt the reliability of our anti-hedonistic intuitions. And finally, I argue that, since in the actual world seeing certain things besides pleasure as ends in themselves may best serve hedonistic ends, hedonism may justify our taking these other things to be intrinsically valuable, thus again making the existence of our seemingly anti-hedonistic intuitions far from straightforward evidence for the falsity of hedonism. (shrink)

Josh Wilburn examines the relationship between Plato's views on psychology and his political philosophy. Focusing on his reflections on the spirited part of the tripartite soul, or thumos, and spirited motivation, he explores the social and political challenges that occupy Plato throughout his works.

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 her Transient Truths, Berit Brogaard defends temporalism about proposition content from the more traditional eternalist views. I argue that both temporalism and eternalism are equally capable of accommodating all the data, and thus suggest that we should adopt a neutralism that holds there is no serious or resolvable dispute. Contra Brogaard, I argue that neither disagreement patterns nor belief dynamics favor temporalism over eternalism. I also suggest that Brogaard's defense of operator over quantificational semantics for tense is unnecessary, because (...) quantificational tense semantics can be given a temporalist reading, and operator tense semantics can be given an eternalist reading. (shrink)

UK blood services, supported by the Health Protection Agency/Health Protection Scotland, carried out an exercise over the summer of 2005 to notify 110 donors whose blood was transfused to three recipients who later developed vCJD. These donors were to be informed that they were now considered 'at risk of vCJD for public health purposes'. The notification began on 20 July 2005 and was completed (barring follow-up) at the end of the first week of October 2005. Apart from two donors who (...) had died, contact was attempted with all donors, including four who were not currently registered with a GP. The lessons learnt about the conduct of such notification have been reviewed. The limited ad hoc feedback available suggests the process and content of this notification was acceptable to donors and their GPs. (shrink)

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.

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)

A diagnosis of schizophrenia is often taken to denote a state of global irrationality within the psychiatric paradigm, wherein psychotic phenomena are seen to equate with a lack of mental capacity. However, the little research that has been undertaken on mental capacity in psychiatric patients shows that people with schizophrenia are more likely to experience isolated, rather than constitutive, irrationality and are therefore not necessarily globally incapacitated. Rational suicide has not been accepted as a valid choice for people with schizophrenia (...) due in part to a belief that characteristic irrationality prevents autonomous decision-making. Since people with schizophrenia are often seen to lack insight into the nature of their disorder, both psychiatric and ethical perspectives generally presume that suicidal acts result directly from mental illness itself and not from second-order desires. In this article, I challenge notions of global irrationality conferred by a diagnosis of schizophrenia and argue that, where delusional beliefs are unifocal, schizophrenia does not necessarily lead to a state of mental incapacity. I then attempt to show that people with schizophrenia can sometimes be rational with regard to suicide, where this decision stems from a realistic appraisal of psychological suffering. (shrink)

ABSTRACT Classical and intuitionistic logic both validate Ex Contradictione Quodlibet, according to which any proposition whatsoever follows from a contradiction. Many philosophers have found ECQ counter-intuitive, but criticisms of the principle have almost universally been directed from a position of support for relevance or other orthodox paraconsistent logics, according to which some, but not necessarily all, propositions follow from a contradiction. This paper draws attention to the historically significant view that nothing whatsoever follows from a contradiction – Ex Contradictione Nihil. (...) It addresses the key arguments – model-theoretic, proof-theoretic, meaning theoretic and holist – deployed by proponents of ECQ against their standard opponents, and shows that each can be defeated from a position of support for ECN. In the course of answering these arguments, some understanding is developed of possible motivations for ECN and a solid case is built that ECN deserves further investigation. (shrink)

Robert Nozick’s oft-quoted review of Tom Regan’s The Case for Animal Rights levels a range of challenges to Regan’s philosophy. Many commentators have focussed on Nozick’s putative defence of speciesism, but this has led to them overlooking other aspects of the critique. In this paper, I draw attention to two. First is Nozick’s criticism of Regan’s political theory, which is best understood relative to Nozick’s libertarianism. Nozick’s challenge invites the possibility of a libertarian account of animal rights – which is (...) not as oxymoronic as it may first sound. Second is Nozick’s criticism of Regan’s axiological theory, which is best understood relative to Nozick’s own axiological inegalitarianism. While Nozick’s axiology has distasteful consequences, it should not be dismissed out-of-hand. Nozick’s challenges to Regan – and Nozick’s wider animal ethics – are rich and original, warranting attention from contemporary theorists for reasons beyond mere historical interest. (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.

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.

Despite its potential for radically reducing the harm inflicted on nonhuman animals in the pursuit of food, there are a number of objections grounded in animal ethics to the development of in vitro meat. In this paper, I defend the possibility against three such concerns. I suggest that worries about reinforcing ideas of flesh as food and worries about the use of nonhuman animals in the production of in vitro meat can be overcome through appropriate safeguards and a fuller understanding (...) of the interests that nonhuman animals actually possess. Worries about the technology reifying speciesist hierarchies of value are more troublesome, however. In response to this final challenge, I suggest that we should be open not just to the production of in vitro nonhuman flesh, but also in vitro human flesh. This leads to a consideration of the ethics of cannibalism. The paper ultimately defends the position that cannibalism simpliciter is not morally problematic, though a great many practices typically associated with it are. The consumption of in vitro human flesh, however, is able to avoid these problematic practices, and so should be considered permissible. I conclude that animal ethicists and vegans should be willing to cautiously embrace the production of in vitro flesh. (shrink)

A total theory of linguistic understanding is often taken to require three subtheories: a syntactic theory, a semantic theory, and a pragmatic theory. The semantic theory occupies an intermediary role – it takes as input structures generated by the syntax, assigns to those structures meanings, and then passes those meanings on to the pragmatics, which characterizes the conversational 1 impact of those meanings. Semantic theories thus seek to explain phenomena such as truth conditions of and inferential relations among sentences/utterances, anaphoric (...) relations among terms, and ambiguity and incoherence of expressions. (shrink)

David Rosenthal and Josh Weisberg have recently provided a counter argument to Ned Block’s argument that a Higher Order Thought (HOT) theory of consciousness cannot accommodate the existence of hallucinatory conscious states (i.e. a conscious episode consisting of a HOT without the presence of a relevant lower order thought). Their counter argument invokes the idea of mental appearances: a non-existent intentional object which is to aid in an account of subjective conscious awareness. I argue that if mental appearances are (...) to do the work they are supposed to, we cannot draw a mental appearance/reality distinction. I provide an alternative story that a HOT theorist can invoke to account for cases of conscious misrepresentation. Such a story will require denying the existence of hallucinatory conscious states while still accounting for conscious misrepresentation. This is a cost I believe the HOT theorist should be willing to pay. (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)

On the face of it Aquinas stands in the mainstream of Western mystical theology, and in particular is a noteworthy proponent of negative theology. This view, however, is challenged within anglophone philosophical theology. The clearest attack on the view that Aquinas is an apophatic theologian is to be found in Eleonore Stump's Aquinas. This paper lays out Stump's reasons for reading Aquinas as non-apophatic, and shows that they are not convincing. Aquinas, it concludes, meant what he said when he claimed (...) that we do not know what God is. (shrink)

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)

Animal rights positions face the ‘predator problem’: the suggestion that if the rights of nonhuman animals are to be protected, then we are obliged to interfere in natural ecosystems to protect prey from predators. Generally, rather than embracing this conclusion, animal ethicists have rejected it, basing this objection on a number of different arguments. This paper considers but challenges three such arguments, before defending a fourth possibility. Rejected are Peter Singer’s suggestion that interference will lead to more harm than good, (...) Sue Donaldson and Will Kymlicka’s suggestion that respect for nonhuman sovereignty necessitates non-interference in normal circumstances, and Alasdair Cochrane’s solution based on the claim that predators cannot survive without killing prey. The possibility defended builds upon Tom Regan’s suggestion that predators, as moral patients but not moral agents, cannot violate the rights of their prey, and so the rights of the prey, while they do exist, do not call for intervention. This idea is developed by a consideration of how moral agents can be more or less responsible for a given event, and defended against criticisms offered by thinkers including Alasdair Cochrane and Dale Jamieson. (shrink)

The same-order representation theory of consciousness holds that conscious mental states represent both the world and themselves. This complex representational structure is posited in part to avoid a powerful objection to the more traditional higher-order representation theory of consciousness. The objection contends that the higher-order theory fails to account for the intimate relationship that holds between conscious states and our awareness of them--the theory 'divides the phenomenal labor' in an illicit fashion. This 'failure of intimacy' is exposed by the possibility (...) of misrepresentation by higher-order states. In this paper, I argue that despite appearances, the same-order theory fails to avoid the objection, and thus also has troubles with intimacy. (shrink)

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.

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)

We note that a plural version of logicism about arithmetic is suggested by the standard reading of Hume's Principle in terms of `the number of Fs/Gs'. We lay out the resources needed to prove a version of Frege's principle in plural, rather than second-order, logic. We sketch a proof of the theorem and comment philosophically on the result, which sits well with a metaphysics of natural numbers as plural properties.

At the outset of the Republic, Polemarchus advances the bold thesis that “justice is the art which gives benefit to friends and injury to enemies”. He quickly rejects the hypothesis, and what follows is a long tradition of neglecting the ethics of enmity. The parallel issue of how friendship affects the moral sphere has, by contrast, been greatly illuminated by discussions both ancient and contemporary. This article connects this existing work to the less explored topic of the normative significance of (...) our negative relationships. I explain how negative partiality should be conceptualized through reference to the positive analogue, and argue that at least some forms of negative partiality are justified. I further explore the connection between positive and negative relationships by showing how both are justified by ongoing histories of encounter. However, I also argue that these relationships are in some important ways asymmetrical. (shrink)

In the tripartite psychology of the Republic, Plato characterizes the “spirited” part of the soul as the “ally of reason”: like the auxiliaries of the just city, whose distinctive job is to support the policies and judgments passed down by the rulers, spirit’s distinctive “job” in the soul is to support and defend the practical decisions and commands of the reasoning part. This is to include not only defense against external enemies who might interfere with those commands, but also, and (...) most importantly, defense against unruly appetites within the individual’s own soul.1 Spirit, according to this picture, is by nature reason’s faithful auxiliary in the soul, while appetite is always a potential enemy to be watched .. (shrink)

The possibility of “clean milk”—dairy produced without the need for cows—has been championed by several charities, companies, and individuals. One can ask how those critical of the contemporary dairy industry, including especially vegans and others sympathetic to animal rights, should respond to this prospect. In this paper, I explore three kinds of challenges that such people may have to clean milk: first, that producing clean milk fails to respect animals; second, that humans should not consume dairy products; and third, that (...) the creation of clean milk would affirm human superiority over cows. None of these challenges, I argue, gives us reason to reject clean milk. I thus conclude that the prospect is one that animal activists should both welcome and embrace. (shrink)

This paper raises the question under what circumstances a plurality forms a set, parallel to the Special Composition Question for mereology. The range of answers that have been proposed in the literature are surveyed and criticised. I argue that there is good reason to reject both the view that pluralities never form sets and the view that pluralities always form sets. Instead, we need to affirm restricted set formation. Casting doubt on the availability of any informative principle which will settle (...) which pluralities form sets, the paper concludes by affirming a naturalistic approach to the philosophy of set theory. (shrink)

The idea of ‘Western Philosophy’ is the product of a legitimation project for European colonialism, through to post-second world war Pan-European identity formation and white supremacist projects. Thus argues Ben Kies (1917-1979), a South African public intellectual, schoolteacher, trade unionist, and activist-theorist. In his 1953 address to the Teachers’ League of South Africa, The Contribution of the Non-European Peoples to World Civilisation, Kies became one of the first people to argue explicitly that there is no such thing as ‘Western philosophy’. (...) In this paper, I introduce Kies as a new figure in the historiography of philosophy with important insights, relevant today. I outline his three key arguments: that ‘Western Philosophy’ is the product of political mythmaking, that it is a recent, largely mid-twentieth century fabrication, and that there is an alternative to ‘Histories of Western Philosophy’, namely ‘mixed’ or entangled histories. I show that Kies’ claims are supported both by contemporary scholarship and bibliometric analysis. I thus argue that Kies is right to claim that the idea of a distinctive, hermetically sealed ‘Western Philosophy’ is a recent, political fabrication and should be abandoned. We should instead develop global, entangled historiography to make sense of philosophy and its history today. (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)

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.

Animal lovers who feed meat to other animals are faced with a paradox: perhaps fewer animals would be harmed if they stopped feeding the ones they love. Animal diets do not raise problems merely for individuals. To address environmental crises, health threats, and harm to animals, we must change our food systems and practices. And in these systems, animals, too, are eaters. -/- Looking beyond what humans should eat and whether to count animals as food, Just Fodder answers ethical and (...) political questions arising from thinking about animals as eaters. Josh Milburn begins with practical dilemmas about feeding the animals closest to us, our pets or animal companions. The questions grow more complicated as he considers relationships with more distance - questions about whether and how to feed garden birds, farmland animals who would eat our crops, and wild animals. Milburn evaluates the nature and circumstances of our relationships with animals to generate a novel theory of animal rights. -/- Looking past arguments about what we can and cannot do to other beings, Just Fodder asks what we can, should, and must do for them, laying out a fuller range of our ethical obligations to other animals. (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)

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”.

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)

• The Static Conception of Semantics (Preliminary Version): A semantic theory should assign a proposition, conceived of as some carrier of meaning that can play the role of truth condition determination, to each (or at least each declarative) sentence.

An important objection to the "higher-order" theory of consciousness turns on the possibility of higher-order misrepresentation. I argue that the objection fails because it illicitly assumes a characterization of consciousness explicitly rejected by HO theory. This in turn raises the question of what justifies an initial characterization of the data a theory of consciousness must explain. I distinguish between intrinsic and extrinsic characterizations of consciousness, and I propose several desiderata a successful characterization of consciousness must meet. I then defend the (...) particular extrinsic characterization of the HO theory, the "transitivity principle," against its intrinsic rivals, thereby showing that the misrepresentation objection conclusively falls short. (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)