Truth and the World

An Explanationist Theory

Jonathan Tallant

• Publisher: Routledge
• Year: 2017
• ISBN:
  9781351388504
• Edition: 1
• Topic: Philosophy
• Subtopic: Philosophy History & Theory

How do we explain the truth of true propositions? Truthmaker theory is the branch of metaphysics that explores the relationships between what is true and what exists. It plays an important role in contemporary debates about the nature of metaphysics and metaphysical enquiry.

In this book Jonathan Tallant argues, controversially, that we should reject truthmaker theory. In its place he argues for an 'explanationist' approach. Drawing on a deflationary theory of truth he shows that it allows us to explain the truth of true propositions and respond to recent arguments that purport to show otherwise. He augments this with a distinction between internally and externally quantified claims: externally quantified claims are claims that quantify over elements of our ontology that play an indispensable explanatory role; internally quantified claims do not. He deploys this union of deflationism and a distinction between kinds of quantification to pursue metaphysical inquiry, sketching the implications for a number of first-order debates, including those in the philosophy of time, modality and mathematics, and also shows how this explanationist model can be used to solve the key problems that afflicted truthmaker theory.

Truth and the World is an important contribution to debates about truth and truthmaker theory as well as metametaphysics, the metaphysics of time and the metaphysics of mathematics, and is essential reading for students and scholars engaged in the study of these topics.

1 In the beginning, there was Truthmaker

Consider an electron. Call it ‘Francis’ – I’m just slightly more imaginative than to just call it ‘e’. The proposition <Francis exists> is true. It’s natural to think that <Francis exists> is true because Francis exists. Two questions then follow. First, are all propositions like this? Are all propositions true because of the existence of some thing or things? Second, what exactly is meant here by ‘because’? How do we spell out the ‘because’ part of the claim that a proposition is true because of the existence of some thing or things? Both questions seem pressing. We must explain how and why it is that true propositions are true.

Truthmaker theorists take this kind of ‘because’ talk very seriously. They will attempt to give some account of it. Their account will feature a relation between truth and world – a truthmaker relation. I say that anyone who appeals to a truthmaker relation between truth and world is a truthmaker theorist. There are three components to such a truthmaker theory: the truths, a truthmaker relation, and the truthmakers (the existents that ‘make true’ the true proposition).

As I will treat the view here, truthmaker theory then comes in two flavors. The first flavor is truthmaker maximalism: all truths require truthmakers – all true propositions stand in a truthmaker relation to a truthmaker (or, some truthmakers). That is, all truths stand in a truthmaker relation to some existent or existents. Representatives of such a view include Armstrong (2004), Cameron (2008c) and Jago (2012) – inter alia. The second flavor of truthmaker theory – non maximalism – holds that only some truths stand in a truthmaker relation to a truthmaker. That is, non-maximalism holds that only some true propositions stand in a truthmaker relation to some existent or existents. Representative, here, are Mellor (2003), Simons (2005), and in an earlier guise, me (Tallant, 2010c) – inter alia.

My overarching argument is as follows. To date, I think that truthmaker theorists have done the best job of explaining why true propositions are true, and I think that the best version of truthmaker theory is truthmaker maximalism. But despite having done the best job to date, I’m going to argue that the maximalist falls short and that truthmaker theory fails. There are three concerns. First, I don’t think that maximalism is (in fact) all that well motivated by some of the arguments in the wider literature (and which I shall attend to shortly). Second, I don’t think that we can locate appropriate truthmakers for all of the truths. Third, the best account of the truthmaker relation itself turns out to not be viable. These are my concerns.

Having shown all of this, I will develop another view – a view that I somewhat tentatively call ‘explanationism’. I argue that this preserves the core insight of truthmaker theory, to which I alluded a moment ago: that there must be (and we must give) an explanation of why true propositions are true. This position ends up committing me to the claim that some truths are true because entities exist, but that the explanations for the truth of other true propositions are not ones that commit us to any existing objects. Because this position has some superficial similarity with truthmaker non-maximalism, I then defend my view from various concerns that have been raised with non-maximalism. I also explain how to deploy this explanationist picture in the service of metaphysical inquiry, exploring a number of first-order debates in metaphysics. This is the task before me.

Why believe my view? Well, for one thing, it preserves what (I claim) motivates truthmaker theory. If you were attracted to that, then you should like this. For another thing, the hypothesis is serviceable and gives us a sensible platform from which we can engage in metaphysical inquiry. And, as we shall see in later chapters, my preferred view also fares well against certain other approaches to metaphysics that are on the market. Ultimately, of course, proof of the theoretical pudding will be in its implementation – and judging how successful that is will require me to engage with first-order debates, proving the use of my approach.

I’ll start with the motivations for truthmaker theory. Following a cursory formal sketch of truthmaker theory and truthmaker maximalism, I’m going to proceed by giving what I hope is a full and detailed account of the motivations for the view that all truths require truthmakers, though for the most part I will steer clear of the issue of explanation. (I’ll return to the matter of explanation in Chapter 7.) I then consider some problems with the view sketched. Borrowing well-known moves in the literature, I refine truthmaker maximalism through a more in-depth discussion of the nature of the truthmaker relation. The end point of this chapter will be a coherent and seemingly well-motivated version of truthmaker maximalism. In Chapters 2 to 6, I will then argue that this – the most well-developed version of the view that all truths require truthmakers – fails. As above, my argument has three parts: truthmaker maximalism cannot preserve that which is supposed to motivate it; truthmaker maximalists cannot locate satisfactory truthmakers for all of the truths; there is no truthmaker relation. I don’t think that any of these claims is original to me, though some of the arguments that I bring forward are. So ends part I.

Part II is more optimistic. I begin (Chapter 7) by explaining how deflationist positions about the nature of truth permit us to satisfy the principal motivation for truthmaker theory – the need to explain why true propositions are true. Such is the central role sometimes afforded to the quest for truthmakers. I then explain (Chapter 8) how to deploy this deflationary account of truth in the service of metaphysical enquiry more generally, bringing to the fore the role of explanation in determining ontological commitment: we are ontologically committed to all and only those entities that play an indispensable explanatory role in our best theories. In Chapter 9 I examine a test case for my proposed methodology – the case of negative existential propositions, and (in Chapter 10) put the methodology to work in three first-order metaphysical debates: the philosophy of time, modality, and the philosophy of mathematics.

Along the way I will offer various arguments for and against specific theories about the nature of the world. Since this is primarily a book about the connection between truth and world, and the ways that we exploit that connection to pursue metaphysical enquiry, these theories and arguments won’t be my focus. Nonetheless I will look to reject particular accounts of the world and offer outline sketches of my preferred ontology. Such limited sketches will prove crucial, as I cannot hope to sketch the connection between truth and world with providing at least a hazy impression of what sits at either end of that connection.

1.1 Truthmaker theory: its introduction and motivation

We must now get clearer on the views under consideration. The remainder of this chapter is primarily exegetical. My concern is not to present the reader with my own take on why one might be tempted to be a truthmaker theorist, but to present to them what has been said (by truthmaker theorists) about why such a view is to be adopted. I will also present responses to those arguments (again, those that have been offered within the literature), in order to give us a stepping-off point. Thus, the main aim of the chapter is to give the reader a sense of where truthmaker theory has come from, in order that I may steer us down a new road to what I take to be a more scenic destination. My starting point for many of the arguments will be Armstrong’s canonical Truth and Truthmaking.

So, to the theory. I borrow (with slight emendation) from Cameron (2008a).¹

Maximalism: for any true proposition, there exists some thing or things that necessitate(s) the truth of that proposition.

(cf. Cameron, 2008a: 292)

Maximalism is an extreme version of truthmaker theory.

The truthmaker theorist merely holds that:

Truthmaker theory: for some true propositions, there exists some thing or things that necessitate(s) the truth of that proposition.

As we move through this chapter, we will have to refine these principles. For one thing, note that this treats necessitation as the truthmaker relation (as do, e.g., both Armstrong (2004) and Cameron (2008a)). I will suggest that mere necessitation is not fit to play the role of the truthmaker relation. Following a number of others (e.g., Schaffer, 2008a, 2008b, 2009: 365), I suggest that the truthmaker relation should be treated as a grounding relation – the ‘in virtue of’ relation. I take this relation to be a primitive and unanalysable relation, though there are things that can be said to cast light on its nature.

Before engaging in the details, I want to bring to the fore an assumption I believe to be widely held. There appears to be a prevailing view in the literature that, if one believes in truthmaker theory at all, then one should believe that all truths have truthmakers; if one believes in truthmaker theory one should default to maximalism. As Cameron (2008b: 107) puts it, with a nice flourish, ‘[w]hat possible reason could one have for thinking of some propositions that they need to be grounded in what there is that doesn’t apply to all propositions?’ Julian Dodd (2007: 400), himself no friend of maximalism, makes a very similar point. For this chapter, I will focus upon other considerations, but I think it is important to keep this assumption in the background, for although I do think that there are reasons that the demand for truthmakers applies to some propositions, not all, I’m going to defer discussion of this issue until later on in the book (9.2.2), and I think that this general point, made by the likes of Cameron and Dodd, is an assumption often in the background in discussions of truthmaker theory.

As already noted, a part of my argument against maximalism is that it cannot be motivated in the way that maximalists have claimed. To make sense of these discussions, we must first be clear on the nature of the arguments that are supposed to motivate maximalism.

1.2 Motivations

Let us start with (arguably) the progenitor of maximalism in its current guise, Armstrong (1997, 2004). From Armstrong’s (2004) work, I think that we can distil (at least) four insights that go some way to motivating truthmaker maximalism, and that are important to the overarching project. My aim in this section is to get clear on these motivations. Those already familiar with Armstrong’s arguments may wish to skip ahead to 1.3.

1.2.1 Against phenomenalism

According to the Phenomenalist, physical objects are constituted by sense-data. A sense datum is, supposedly, a mind-dependent object that is the direct object of perception. Crudely then, given Phenomenalism, an object is nothing more than a collection of mind-dependent objects that are the direct objects of perception.

There is an obvious concern with Phenomenalism. It is very natural to suppose that there exist objects that are not being observed. For example, when I leave a room, I do not think that its contents mysteriously disappear, only to re-appear when I (or some other perceiver) return. Indeed, the very natural assumption is that the contents of the room persist through any period of time during which they are not perceived. As natural as this assumption is, the problem for the Phenomenalist is that sense-data do not exist unperceived. Sense data are the direct objects of perception and are dependent for their existence on the mind of a perceiver. Where Berkeley posited an all-perceiving God to ensure the continued existence of sense-data, Phenomenalists take a different route. Instead of appealing to a God, an agent in whose mind the sense data can persist in the absence of being perceived by any other agent, Armtstrong’s Phenomenalist appeals to true counterfactuals. To illustrate: suppose that I leave the room and close the door behind me, obscuring everyone’s view of the table in the room. It is nonetheless true, claims Armstrong’s (2004: 1) interpretation of the Phenomenalist, that, ‘were some perceiver to open the door, they would perceive the table’. This counterfactual, claims the Phenomenalist, is true.

There is something strange about true counterfactuals such as this one, however. It seems as if the order of explanation is wrong. We would normally say that the counterfactual were some perceiver to open the door, then they would perceive the table is true, at least in part because of the existence of the table. We think that the counterfactual is true because the existence of the table grounds it in some way. However, the Phenomenalist has this order of explanation the other way around. The Phenomenalist thinks that we may say that there exists an unperceived object, because the counterfactual is true. This seems deeply counterintuitive. It seems wrong to say that the table exists unperceived because the counterfactual is true.

As counterintuitive as it may seem, we still need some way to articulate what is supposed to be wrong with the Phenomenalist view. It is here that we will find truthmakers are useful. According to Armstrong (2004: 2), by asking ‘what makes true these counterfactual claims?’ we cut to the heart of the problem. For

what answer had the actual Phenomenalists got? All these philosophers had available for truthmakers were the actual sense-data or sense-impressions had by actual minds.

Of course, the actual sense-data don’t seem to make true these counterfactuals. After all, what actual sense-data make true <were I to open the door I would perceive something that no-one is now perceiving>? All of the actually existing sense data are compatible with the falsity of <were I to open the door I would perceive something that no-one is now perceiving>. It seems hard, then, to treat the alleged truthmaker as a truthmaker. Armstrong (2004: 2) sees it as a benefit of truthmaker theory that it allows us to articulate a powerful – if not conclusive – argument against Phenomenalism.

More generally (and importantly for Chapter 2): proponents of truthmaker theory claim (rightly or wrongly) that there is a sense in which we may use truthmaker theory in order to rule out particularly suspect metaphysical positions. In the case of Phenomenalism, we find that truthmaker theory enables us to precisely articulate what it is that is wrong with the view. The Phenomenalist simply cannot locate the right kinds of explanation for the truth of the true propositions.

And, as one might expect, this consideration quite naturally leads us into maximalism. To demonstrate, suppose that we merely adopted truthmaker theory and fell short of endorsing maximalism; only some truths require truthmakers. Such a thesis would do nothing to threaten the Phenomenalist. The Phenomenalist can agree with us that some truths have truthmakers. To block Armstrong’s concern, they may simply deny that modal truths (or just a sub-set of the modal truths including the troublesome counterfactuals described) require truthmakers. To prevent this response from the Phenomenalist, and so to develop the argument against Phenomenalism, we require truthmaker maximalism: all truths require truthmakers. We cannot weasel out of the demand for truthmakers for these troublesome counterfactuals. Thus we should endorse maximal...

Table of contents

• Cover
• Title
• Copyright
• Contents
• Acknowledgements
• Introduction
• 1 In the beginning, there was Truthmaker
• 2 Dubious by nature
• 3 Molnar and negative ontology
• 4 Modern, negative metaphysics
• 5 Priority
• 6 Aptness
• 7 From truth to explanation
• 8 Truth and metaphysics
• 9 Truth and negative existential propositions
• 10 Applications
• Bibliography
• Index