Sam Baron

Presentism faces a familiar objection from truthmaker theory. How can propositions about the past be made true if past entities do not exist? In answering this question, there are, broadly, two roads open to the presentist. The easy road to presentism proceeds by capitulating to the demands imposed by truthmaker theory and finding truthmakers for claims about the past. This road typically involves the invocation of controversial metaphysical posits that must then be defended. The hard road to presentism resists the demands of truthmaker theory by denying that all truths must be truth-made. The road is hard as it requires providing a principled restriction on the scope of truthmaker theory. In this paper, I argue that the hard road collapses back into the easy road; there is no hard road to presentism.

Is time necessary for causation? We argue that, given a counterfactual theory of causation, it is not. We defend this claim by considering cases of counterfactual dependence in quantum mechanics. These cases involve laws of nature that govern entanglement. These laws make possible the evaluation of causal counterfactuals between space-like separated entangled particles. There is, for the proponent of a counterfactual theory of causation, a possible world in which causation but not time exists that can be reached by ‘stripping out’ time from the actual world, leaving quantum mechanical laws intact.

Presentism faces a serious challenge from truthmaker theory. Standard solutions to the truthmaker objection against presentism proceed in one of two ways. Easy road presentists invoke new entities to satisfy the requirements of truthmaker theory. Hard road presentists, by contrast, flatly refuse to give in to truthmaker demands. Recently, a third way has been proposed. This response seeks to address the truthmaking problem by tensing our truthmaker principles. These views, though intuitive, are under-developed. In this paper, I get serious about a fundamentally tensed approach to truthmaking by sketching out the underlying ontological picture needed to make sense of tensed truthmaker theory.

There has been a recent surge of interest in mathematical explanations of empirical facts. A number of putative cases of such explanation have been identified, and used to provide support for an explanatory version of the indispensability argument for mathematical platonism. In this paper, I consider the prospects for developing a metaphysically light-weight theory of mathematical explanations by appealing to the resources currently available in existing work on applied mathematics and scientific explanation. I argue that new resources must be marshalled to handle the mathematical case, and sketch out one option for doing so.

The present paper advances an analogy between cases of extra-mathematical explanation and cases of what might be termed ‘extra-logical explanation’: the explanation of a physical fact by a logical fact. A particular case of extra-logical explanation is identified that arises in the philosophical literature on time travel. This instance of extra-logical explanation is subsequently shown to be of a piece with cases of extra-mathematical explanation. Using this analogy, we argue extra-mathematical explanation is part of a broader class of non-causal explanation. This has important implications for extra-mathematical explanation, for time travel and for theories of explanation more generally.

Truthmaker theory is commonly thought to pose a challenge for presentism. Presentism seems to lack the ontological and ideological resources required to adequately underwrite the truth of propositions concerning the past. That is because if presentism is true, then the past does not exist. According to the standard response to this challenge, the truth of propositions concerning the past supervenes on surrogate entities that ‘stand proxy’ for past things. I argue that in order for the standard response to the truthmaker challenge to succeed these surrogate entities must stand in necessary connections to the past. I go on to argue that because the standard response is already committed to denying the existence of cross-temporal modal connections of this kind, by its own lights that response is in error.1.

Recently, nominalists have made a case against the Quine–Putnam indispensability argument for mathematical Platonism by taking issue with Quine’s criterion of ontological commitment. In this paper I propose and defend an indispensability argument founded on an alternative criterion of ontological commitment: that advocated by David Armstrong. By defending such an argument I place the burden back onto the nominalist to defend her favourite criterion of ontological commitment and, furthermore, show that criterion cannot be used to formulate a plausible form of the indispensability argument.

This paper seeks to differentiate negative properties from positive properties, with the aim of providing the groundwork for further discussion about whether there is anything that corresponds to either of these notions. We differentiate negative and positive properties in terms of their functional role, before drawing out the metaphysical implications of proceeding in this fashion. We show that if the difference between negative and positive properties tabled here is correct, then negative properties are metaphysically contentious entities, entities that many philosophers will be unwilling to countenance.

This paper draws together two strands in the debate over the existence of mathematical objects. The first strand concerns the notion of extra-mathematical explanation: the explanation of physical facts, in part, by facts about mathematical objects. The second strand concerns the access problem for platonism: the problem of how to account for knowledge of mathematical objects. I argue for the following conditional: if there are extra-mathematical explanations, then the core thesis of the access problem is false. This has implications for nominalists and platonists alike. Platonists can make a case for epistemic access to mathematical objects by providing evidence in favour of the existence of extra-mathematical explanations. Nominalists, by contrast, can use the access problem to cast doubt on the idea that mathematical objects play a substantive role in scientific explanation.

Much current debate in the metaphysics of time is between A-theorists and B-theorists. Central to this debate is the assumption that time exists and that the task of metaphysics is to catalogue time’s features. Relatively little consideration has been given to an error theory about time. Since there is very little extant work on temporal error theory the goal of this paper is simply to lay the groundwork to allow future discussion of the relative merits of such a view. The paper thus develops a conceptual framework from within which to evaluate claims about the actual existence, or not, of temporality as that notion appears in folk discourses about time, and from there to examine claims about the counterfactual existence, or not, of temporality so conceived. We subsequently apply this framework to three extant positions drawn from physics and metaphysics that deny the existence of time. We show that only one of these positions is a folk temporal error theory; that is, a view that denies the existence of time as that notion is operative in our everyday thought and talk.

This paper offers a new way to evaluate counterfactual conditionals on the supposition that actually, there is no time. We then parlay this method of evaluation into a way of evaluating causal claims. Our primary aim is to preserve, at a minimum, the assertibility of certain counterfactual and causal claims once time has been excised from reality. This is an important first step in a more general reconstruction project that has two important components. First, recovering our ordinary language claims involving notions such as persistence, change and agency and, second, recovering enough observational evidence so that any timeless metaphysics is not empirically self-refuting. However, the project of investigating causation in a timeless setting has a greater relevance than its application to timeless physical theory alone. For, as we show, it can be used to model the assertibility conditions of causal claims more generally.