In his Truth and Ontology,1 Trenton Merricks argues against the truthmaker principle: Truthmaker: ∀p( p → ∃xxᮀ(Exx → p)). Truthmaker says that for any true proposition, there are some things whose existence guarantees the truth of that proposition: that is, some things which couldn’t all exist and the proposition fail to be true. His main arguments against Truthmaker are that there cannot be satisfactory truthmakers for (i) negative existentials, (ii) modal truths, (iii) truths about the past (given that presentism is (...) true) and (iv) certain subjunctive conditionals, in particular so-called ‘counterfactuals of freedom’ and dispositional conditionals. I’m going to concentrate on the first three of these. But first I’ll say a bit about why we should care about Truthmaker. Merricks says that “No one gives much of an argument for Truthmaker. Instead, Truthmaker’s main support comes from something like the brute intuition that what is true depends in a non-trivial way on what there is” ( p. 2). He is, unfortunately, correct that truthmaker theorists have in general not been very good at motivating their theory. Too often is Truthmaker taken to be obvious, or an obvious consequence of realism, when really it is neither. But I think we can do better. (shrink)

Most of us would want to say that it is true that Socrates taught Plato. According to realists about past facts,1 this is made true by the fact that there is, located in the past, i.e., earlier than now, at least one real event that is the teaching of Plato by Socrates. Presentists, however, in denying that past events and facts exist2 cannot appeal to such facts to make their past-tensed statements true. So what is a presentist to do?

Most of us would want to say that it is true that Socrates taught Plato. According to realists about past facts, this is made true by the fact that there is, located in the past, i.e., earlier than now, at least one real event that is the teaching of Plato by Socrates. Presentists, however, in denying that past events and facts exist cannot appeal to such facts to make their past-tensed Statements true. So what is a presentist to do?There are (...) at least three conditions that would ideally be met in a satisfactory solution to this problem:a) It must preserve our views about which Statements are true and which falseb) It must be transparent what the truthmakers are for those Statementsc) It must accommodate the truth-value links between various times. (shrink)

Challenging the myth that mathematical objects can be defined into existence, Bigelow here employs Armstrong's metaphysical materialism to cast new light on mathematics. He identifies natural, real, and imaginary numbers and sets with specified physical properties and relations and, by so doing, draws mathematics back from its sterile, abstract exile into the midst of the physical world.

This book argues that the only kind of metaphysics that can contribute to objective knowledge is one based specifically on contemporary science as it really is, and not on philosophers' a priori intuitions, common sense, or simplifications of science. In addition to showing how recent metaphysics has drifted away from connection with all other serious scholarly inquiry as a result of not heeding this restriction, this book demonstrates how to build a metaphysics compatible with current fundamental physics, which, when combined (...) with metaphysics of the special sciences, can be used to unify physics with the other sciences without reducing these sciences to physics itself. Taking science metaphysically seriously, this book argues, means that metaphysicians must abandon the picture of the world as composed of self-subsistent individual objects, and the paradigm of causation as the collision of such objects. The text assesses the role of information theory and complex systems theory in attempts to explain the relationship between the special sciences and physics, treading a middle road between the grand synthesis of thermodynamics and information, and eliminativism about information. The consequences of the books' metaphysical theory for central issues in the philosophy of science are explored, including the implications for the realism versus empiricism debate, the role of causation in scientific explanations, the nature of causation and laws, the status of abstract and virtual objects, and the objective reality of natural kinds. (shrink)

I thank my commentators for their kind words, and for their close reading and challenging criticisms of my book. I have chosen selective and substantive replies. Those criticisms I ignore, I ignore because I have little more to say, not because they are unworthy of discussion.

Persistence through time is like extension through space. A road has spatial parts in the subregions of the region of space it occupies; likewise, an object that exists in time has temporal parts in the various subregions of the total region of time it occupies. This view — known variously as four dimensionalism, the doctrine of temporal parts, and the theory that objects “perdure” — is opposed to “three dimensionalism”, the doctrine that things “endure”, or are “wholly present”.1 I will (...) attempt to resolve this dispute in favor of four dimensionalism by means of a novel argument based on considerations of vagueness. But before argument in this area can be productive, I believe we must become much clearer than is customary about exactly what the dispute is, for the usual ways of formulating the dispute are flawed, especially where three dimensionalism is concerned. (shrink)

Modal Fictionalism, the theory that possible worlds do not literally exist but that our talk about them should be understood in the same way that we understand talk about fictional entities, is an increasingly popular approach to possible worlds. This paper will distinguish three versions of Modal Fictionalism, and will show that the third, a version endorsed by some of the most prominent Modal Fictionalists, faces at least three serious objections: that it makes modality too artificial, the modal fiction does (...) not have the representative resources it needs, and the approach has trouble accounting for propositions. (shrink)

According to the indispensability argument, the fact that we quantify over numbers, sets and functions in our best scientific theories gives us reason for believing that such objects exist. I examine a strategy to dispense with such quantification by simply replacing any given platonistic theory by the set of sentences in the nominalist vocabulary it logically entails. I argue that, as a strategy, this response fails: for there is no guarantee that the nominalist world that go beyond the set of (...) sentences in the nominalist language such theories entail. However, I argue that what such theories show is that mathematics can enable us to express possibilities about the concrete world that may not be expressible in nominalistically acceptable language. While I grant that this may make quantification over abstracta indispensable, I deny that such indispensability is a reason for accepting them into our ontology. I urge that the nominalist should be allowed to quantify over abstracta whilst denying their existence and I explain how this apparently contradictory practice (a practice I call 'weaseling') is in fact coherent, unproblematic and rational. Finally, I examine the view that platonistic theories are simpler or more attractive than their nominalistic reformulations, and thus that abstract ought to be accepted into our ontology for the same sorts of reasons as other theoretical objects. I argue that, at least in the case of numbers, functions and sets, such arguments misunderstand the kind of simplicity and attractiveness we seek. (shrink)

(1) The average Mum has 2.4 children. (2) The number of Argle’s fingers equals the number of Bargle’s toes. (3) There are two possible ways in which Joe could win this chess game. In the right contexts, and outside the philosophy room, all the above sentences may be completely uncontroversial. For instance, if we know that Joe could win either by exchanging queens and entering an endgame, or by initiating a kingside attack then, if ignorant of Quine’s work on ontology, (...) we would take (3) to be uncontroversially true. (shrink)

The presentist view of time is psychologically appealing. I argue that, ironically, contingent facts about the temporal properties of consciousness are very difficult to square with presentism unless some form of mind/body dualism is embraced.

In this paper, we show that presentism -- the view that the way things are is the way things presently are -- is not undermined by the objection from being-supervenience. This objection claims, roughly, that presentism has trouble accounting for the truth-value of past-tense claims. Our demonstration amounts to the articulation and defence of a novel version of presentism. This is brute past presentism, according to which the truth-value of past-tense claims is determined by the past understood as a fundamental (...) aspect of reality different from things and how things are. (shrink)

Jonathan Westphal's recent paper attempts to reconcile the view that propositions about the future can be true or false now with the idea that the future cannot now be real. I attempt to show that Westphal's proposal is either unoriginal or unsatisfying. It is unoriginal if it is just the well-known eternalist solution. It is unsatisfying if it is instead making use of a peculiar, tensed truthmaking principle.

This paper argues that a consideration of the problem of providing truthmakers for negative truths undermines truthmaker theory. Truthmaker theorists are presented with an uncomfortable dilemma. Either they must take up the challenge of providing truthmakers for negative truths, or else they must explain why negative truths are exceptions to the principle that every truth must have a truthmaker. The first horn is unattractive since the prospects of providing truthmakers for negative truths do not look good neither absences, nor totality (...) states of affairs, nor Graham Priest and J.C. Beall’s ‘polarities’ (Beall, 2000; Priest, 2000) are up to the job. The second horn, meanwhile, is problematic because restricting the truthmaker principle to atomic truths, or weakening it to the thesis that truth supervenes on being, undercuts truthmaker theory’s original motivation. The paper ends by arguing that truthmaker theory is, in any case, an under-motivated doctrine because the groundedness of truth can be explained without appeal to the truthmaker principle. This leaves us free to give the ommonsensical and deflationary explanation of negative truths that common-sense suggests. (shrink)

The presentist view of time is psychologically appealing. I argue that, ironically, contingent facts about the temporal properties of consciousness are very difficult to square with presentism unless some form of mind/body dualism is embraced.