Metaphysics

An Introduction

Jonathan Tallant

• Publisher: Bloomsbury Academic
• Year: 2017
• ISBN:
  9781350006744
• Edition: 2
• Topic: Philosophy
• Subtopic: Philosophical Metaphysics

If the sentence 'my cat is on the mat' is true how does it get to be true? Sentences are made true by what exists. But what about claims such as 'There were dinosaurs?' and '2+2=4'. How do they get to be true? Metaphysics: An Introduction uses the idea of truth and the quest for truth-makers to unravel philosophical problems in contemporary metaphysics. From the nature of properties and time to causation and objects, truth becomes a guiding theme to understanding metaphysical concepts and debates. In response to feedback from students and instructors, the Second Edition has been updated with new material in a range of chapters, including discussions of recent research concerning the nature of physical objects, time and modality. Recommended readings have been revised to ensure an improved gender balance while explanations and ideas are easier to follow. Together with a glossary and discussion questions, each chapter concludes with a series of mind maps to help visualise the logical space being explored and how the arguments push in different directions. Metaphysics: An Introduction is suitable for anyone studying metaphysical problems for the first time.

An introduction to truth-making

1

Chapter outline

Truth-making: maximalism and necessitarianism

The nature of the relation

Metaphysics and physics

Metaphysical desiderata and tools

Intuitions

Summing up and using this book

Let’s begin by considering a seemingly straightforward question: If the sentence ‘my cat is on the mat’ is true, how does it get to be true? The most obvious answer to the question would seem to be that the sentence is true because my cat exists, the mat exists and the cat is on the mat. Put another way: the world includes my cat being on the mat. Likewise, that ‘a tomato is red’ is true is due to there existing a red tomato. As I write, the claim that ‘Barack Obama is the president of the United States’ is true, because Barack Obama exists, the United States exists and Barack Obama is the president of the United States. (Though by the time you read this, it may well be apt to swap this for ‘Donald Trump is the president of the United States.’) Thus, we might think, some existing thing or things make the sentence ‘Barack Obama is the president of the United States’ true. And while things will prove a little more complex when we get into the details, the very natural thought, seemingly underpinning these explanations, is that sentences are true because of what exists. For instance, when we say that ‘“the tomato is red” is true,’ we say this because there exists a red tomato. In anticipation of some terms that we will deploy later on, we may say that it looks like these sentences are made true by what exists. Perhaps you think that’s a trivial result; of course our claims are true only if they are made true by what exists in the world. It’s obvious from consideration of the foregoing and many other sentences like them that the world makes true what it is that we say. What could be more obvious?

Let’s pause for a moment to state that intuition in a semi-formal fashion. To begin with, we will follow convention and allow that when we wish to indicate that something is a proposition, we will deploy angle brackets around it, such that <p> states the proposition that p. Roughly speaking, a proposition is taken to be that which is expressed by a particular sentence, and sentences in different languages can be used to express the same proposition. Thus, ‘it is raining’ and ‘il pleut’ both express the same proposition.

Using this notation, we can then say that the proposition p – which we write as <p> – is true if, and only if, some existing thing or things make(s) it true. Call this the ‘truth-maker’ (TM) thesis.

TM: <p> is true if, and only if, it is made true by some existing thing or things.

Now, although it might seem as if TM is a natural and intuitive principle, one that should be adopted without a second thought, a moment’s consideration of TM reveals that it will have surprising and far-reaching implications for a variety of discourses. Consider, for instance, <it’s possible that I not write this book>. At least intuitively the proposition seems true (and for the time being let’s assume that it is). So let’s ask the obvious question: we’ve accepted TM, so what makes true <it’s possible that I not write this book>? According to the very plausible principle TM, some existing thing (or things) must make it true – but what?

What are our options? Perhaps, we might think, it’s my actions that make true <it’s possible that I not write this book>. But, at least upon first inspection, that doesn’t look right. After all, I am writing the book! So, the actions that I in fact perform don’t seem to tell me anything about what I could, but do not in fact, do. It’s unclear how my actions can then also make true <it’s possible for me to not write this book>. By way of refinement we might then say that I make it true by having particular abilities: since I might have chosen to exercise those abilities in a different way (perhaps by writing research papers instead), it is the case that I make it true that it is possible that I not write this book.

Although this looks more promising as an account of what makes true <it’s possible that I not write this book>, problems arise. For instance, we said that it was my having particular abilities that make true <it’s possible that I not write this book>. But what sort of abilities? Presumably, what we mean to say is that I could have behaved in a way that I did not, and that I could have behaved in that particular way (lying on the sofa, rather than writing a book) makes true <it’s possible that I not write this book>. But what we might find potentially troublesome about such thoughts is that we’re now saying that what makes true <it’s possible that I not write this book> is simply that I could have behaved in a way that I did not. That, in turn, looks to say nothing more than it’s possible for me to behave in a way that I did not! It seems, therefore, that we’re still lacking an account of what it is that makes true <it’s possible that I not write this book>. What is it, then, that exists and makes true our talk about what is possible?

Clearly, the foregoing is far from exhaustive and appears a little in the abstract at this stage. We’ll return to a discussion of what makes true claims about what’s possible (and necessary – the so-called modal truths) in Chapter 4. For the time being, though, my intention is simply to point out that endorsing TM leads us to search for truth-makers for all truths. That is, every single true claim that we make is such that some existing portion of reality makes it true. This is, indeed, the attitude taken by a number of contemporary metaphysicians. For our purposes, then, we are going to treat metaphysics as a quest for truth-makers.

That is going to lead us to make some surprising claims. Just to whet the appetite a little, consider the following putative truths.

<2 + 2 = 4> – what makes that true? Are there really such things as numbers? (Chapter 3)

<There were dinosaurs> – what makes that true? Does the past really exist? (Chapter 7)

<The collapse in the sub-prime mortgage market caused the 2008 financial crisis> – what makes that true? What is it for one thing to cause another? (Chapter 9)

Questions like these have concerned metaphysicians for years, and in this book we’ll be considering these questions and others like them. Of course, there are other questions that have vexed philosophers, too. Questions such as ‘Is killing wrong?’ and ‘Is the Mona Lisa beautiful?’ all fall within the purview of philosophy more generally, and if one thought that the answer to these questions is ‘yes’, then it may well be appropriate for us to then go on to seek out truth-makers for these claims, which in turn may involve us doing some metaphysics. However, considering the nature of truth-makers required within these domains would take us away from what may be considered to be mainstream metaphysics into the domains of (meta)ethics and aesthetics and various branches of metaphysics that I’m not going to engage with. Our focus here is narrower and concerns debates that are, as a matter of historical fact, more often treated as core subjects in metaphysics. Of course, this threatens to steer us in the direction of trying to specify what philosophy is or of trying to specify what metaphysics is. Quite deliberately, I’m not going to engage with those questions directly. My aim here is to introduce various topics in metaphysics (itself a discipline within philosophy) without trying to say what either metaphysics or philosophy are. To do otherwise would require another book. I’ll get to writing that one soon!

It’s appropriate here for me to alert the readers to an issue they ought to be aware of. Many of the debates that we look at during the course of the book were not, at least when originally considered, presented in terms of either seeking or providing truth-makers for true propositions. Indeed, the endorsement of TM as a philosophical theory is both recent (only really being brought to light in Mulligan, Simons and Smith 1984) and contentious (as we shall see in Chapter 10).

I have deliberately chosen to present the issues that we will cover in this book as ones dependent upon the idea of truth-making, for two principal reasons: first, treating TM as a means by which to present the various different areas allows for a clean and unified presentation of the issues and provides the reader with a constant theme that runs through the book; second, it’s at least plausible that something very much like TM has underpinned much metaphysical thinking, both in the last hundred years or so and much earlier. So, although it is a little inappropriate to present all of metaphysics as in the thrall of truth-making, presenting these issues in the way that I do is not without some justification. Nonetheless, the reader should keep in mind that there is more to metaphysics than the quest for truth-makers. Some of the dialectically significant features of the debates will be discussed in a moment.

Truth-making: maximalism and necessitarianism

In the last section we noted that TM is pretty plausible, but you might then have been somewhat taken aback at the suggestion that propositions like <2 + 2 = 4> need truth-makers. Surely, we might think, although true propositions about things like cats, mats, tables and chairs need to be made true by what exists, it’s altogether more radical and less intuitive to think that true mathematical propositions require some existing thing to make them true.

Although such sentiment is understandable, it seems to sit uneasily with TM. It seems that if we’re going to think that some truths have truth-makers, then we should think that they all do. And since we do think that some propositions require truth-makers, we should think that all truths require truth-makers. As Cameron (2008a: 107) puts it, with something of a 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?’

Let’s flesh out this thought a little. Suppose we think that propositions such as <the tomato is red> need truth-makers in order to be true. Presumably, the intuition that is in part motivating this thought is that what is true depends upon what exists. Certainly, one finds that idea ably expressed in the literature on truth-making:

My hope is that philosophers of realist inclinations will be immediately attracted to the idea that a truth, any truth, should depend for its truth on something ‘outside’ it, in virtue of which it is true. (Armstrong 2004: 7)

[T]‌he root of the idea of truthmakers is the very plausible and compelling idea that the truth of a proposition is a function of, or is determined by, reality. (Rodriguez-Pereyra 2005: 20)

[w]‌e are looking for reasons from the side of the world as to why a certain proposition is true. (Simons 2005: 254)

Truth must, one expects, depend in some way on reality. (Mumford 2005: 263)

To borrow the language from the last of these quotations and relate this back to number talk: if we think that <2 + 2 = 4> is true, then, presumably, we are looking for some portion of reality upon which the truth of <2 + 2 = 4> can depend, some existent that is responsible for the truth of the proposition. That is a request for a truth-maker. We are looking for ‘reasons from the side of the world’ as to why this proposition is true.

My favourite statement of this idea, that truth must in some way be fixed by the nature of the world, is due to Karen Bennett, even if she does put it somewhat controversially:

Truth – or, better, truth-value – depends on being. I find this intuition very plausible. After all, what’s the alternative? That truth floats free of being? Surely that’s the kind of thought that leads to berets, and a job in a bad Comp Lit department. (Bennett 2011: 187)

In any case, if we think that propositions about tomatoes need to be made true by existing objects, then we’ll need some pretty good reasons to think that true talk about numbers doesn’t need to be made true in exactly the same way. If we only endorse TM with regard to some truths, and not others, then it looks as if we will be charged with an unprincipled application of TM to some domains and not others: this looks decidedly ad hoc. It looks very much as if by endorsing TM we are endorsing the thought that what’s true depends on what exists. So, let us proceed on the basis that all truths need truth-makers.

We have found that a natural extension of TM is that for every truth, some thing or things makes that proposition true. This view is described, in the literature, as Truth-Maker Maximalism, or TM-Max. Thus,

TM-Max: For any <p>, <p> is true if, and only if, it is made true by some existing thing or things.

The nature of the relation

Suppose we grant TM-Max. It still seems we have an important question to answer: what is it for the world to make true a particular proposition? More precisely, what is the truth-making relation? It would be good if we could say something informative about this relation, if only to get clarity on the details of the view.

Typically, the truth-making relation is thought to be something like the relation of necessitation. That is, whenever something exists, it necessitates certain truths about it. To see why, let us return our attention to our now familiar red tomato. The thought of the truth-maker theorist is that the existence of a red tomato necessitates the truth of <the tomato is red>. It is impossible for that proposition to be false if there exists a red tomato. Well, that sounds plausible. Likewise, the existence of the red tomato will necessitate the truth of <there is a tomato> and <there is a red thing>. After all, it is impossible for there to be a red tomato and <there is a tomato&g...