Nicholas Rimell

In this brief introductory chapter, I present my project as an attempt to provide a unified and satisfactory response to three difficult questions about mental representation. First, must thinking involve standing in a relation to the object of thought, and if so how (if at all) can we think about nonexistents? Second, do egocentric beliefs have a special kind of egocentric representational content, i.e., do they represent the world as being a certain way that third personal beliefs cannot represent the world as being? Third, is the representational content of our thinking wholly determined by what’s ‘in the head’ and by how things seem to us from our own perspectives, or is it in part determined (and not just caused) by our environments?

The goal of this chapter is to characterize the debate between externalists and internalists about representational mental content. I first distinguish this debate from subtly different debates. I then lay out the main argument for externalism. The argument’s crucial premise is Content Fixes Truth (CFT), the claim that thoughts cannot have the same representational content while differing in truth value. If CFT is true, internalism is false and externalism is true. I devote the remainder of the chapter to laying out the main argument for CFT and then presenting some compelling internalist responses, including David Chalmers’s appeal to the distinction between subjunctive and epistemic content.

The best alternative to the error theory proposed in Chapter 5 centers on necessitism, the claim that, necessarily, whatever exists exists necessarily. There is a popular argument for necessitism that starts from the idea that a singular proposition—a proposition that is directly about something—can exist only if what it is directly about exists as well. This argument raises a special worry for me since, it turns out, some of the best ways of resisting this argument are at odds with my own argument in Chapter 5. I argue, however, that the argument for necessitism fails for reasons that are unrelated to my argument in Chapter 5. I argue, further, that in order to make sense of causation we must reject necessitism.

Building on my argument in Chapter 3, I argue that the first tenet of the traditional doctrine of belief has an additional consequence: our egocentric beliefs are attitudes toward private propositions. In defending this argument, I argue against the standard way of making sense of what is special about egocentric belief, which is to appeal to the guises by which we entertain third-personal propositions. My argument may lead some to reject the first tenet of the traditional view of belief. I argue that the better option is to endorse the first tenet of the traditional doctrine and, along with it, both externalism and the view that our egocentric beliefs are attitudes toward private propositions. In arguing for this, I offer an account of first-personal assertion.

The traditional doctrine of belief goes back to Frege and consists of two theses. First, necessarily, beliefs are attitudes toward—and, consequently, inherit the contents of—propositions. Second, necessarily, propositions have truth values, and they have these truth values absolutely. Thus, there are no relativized propositions. It is commonly recognized that these two tenets jointly entail Content Fixes Truth (CFT), the claim that thoughts cannot have the same content while differing in truth value. I argue that the traditional doctrine’s first tenet, all by itself, entails CFT and, accordingly, entails that externalism is true whereas internalism is false.

Serious actualism says that, necessarily, whatever instantiates a property exists. One consequence of this claim is that, if the act of thinking constitutively involves a thinker’s standing in a relation to an object of thought, then it is impossible to think about nonexistents. I present an argument that is clearly valid. I then argue that, to make sense of the validity of this argument, we must accept that thinking constitutively involves a relation to an object of thought, at least given the results of previous chapters. Since I accept serious actualism, I conclude that it is impossible to think about nonexistents. I then offer an error theory meant to explain what we are doing when we think we’re thinking about nonexistents. In these cases, I say, we’re really thinking about (non-coexemplified) properties.

In this brief conclusion, I discuss the way in which the main claims defended in this book hang together. The first tenet of the traditional doctrine of belief says that, necessarily, if two thoughts share representational content (of some sort), then they are attitudes toward—and, consequently, inherit the representational content of—the same proposition. I have argued from this ontological claim to an account of mental representation according to which: representational mental content is wide; egocentric beliefs are attitudes toward private propositions; and thought constitutively involves our standing in relations to the objects of thought, from which it follows that we cannot think about nonexistents. These claims are mutually supportive. For instance, appealing to private propositions helps us to defend externalism against an otherwise daunting objection.

Recently, a number of philosophers have argued that, despite appearances, the success of Don Marquis's well-known future-like-ours argument against abortion does not turn, in an important way, on the metaphysics of identity. I argue that this is false. The success of Marquis's argument turns on precisely two issues: first, whether it is prima facie seriously wrong to deprive something of a future like ours; second, whether, in a counterfactual circumstance in which an abortion does not occur, the foetus is numerically identical with something that, later on, experiences a life like ours. Since the former claim is plausible (albeit disputable), the success of Marquis's argument does turn on the metaphysics of identity in an important way. Before defending a positive argument for this position, I consider what I take to be the most promising way of challenging it. This involves a recent objection to Marquis by Tim Burkhardt (2021). Burkhardt claims that his objection floats free of the metaphysics of identity. I argue that it fails to do so, and that in fact it fails outright. I end by considering the relationship between my arguments and the question of what matters in survival.

We argue that the future-like-ours argument against abortion rests on an important assumption. Namely, in the first trimester of an aborted pregnancy, there exists something that would have gone on to enjoy conscious mental states, had the abortion not occurred. To accommodate this assumption, we argue, a proponent of the future-like-ours argument must presuppose that there is ontic vagueness. We anticipate the objection that our argument achieves “too much” because it also applies mutatis mutandis to conscious humans. We respond by showing that an explanation can be given for why it is wrong to kill conscious humans that is independent of the underlying metaphysics. Our response brings into focus a reason why—at least in the context of an ethical argument like the future-like-ours argument—appeal to a highly controversial metaphysics is ad hoc. Such metaphysics is not necessary to explain the wrongness of killing conscious humans, only nonconscious fetuses.

On its usual interpretation, the Barcan Formula—◊∃xBx → ∃x◊Bx—says that, if there could have been something that is such and such a way, then there is something that could have been that way. It is traditionally held that contingentist actualists should—indeed, must—reject the Barcan Formula. I argue that contingentist actualists should—indeed, must—endorse the Barcan Formula, at least assuming a standard, Tarskian conception of truth and truth preservation. I end by proposing a logic for contingentist actualists that validates the Barcan Formula. This logic has the surprising feature of also validating the Converse Barcan Formula, □∀xBx → ∀x□Bx, while still invalidating related formulas—such as □∀x□∃y x=y (NNE)—that contingentist actualists should reject. It does this by employing models with fixed domains but assignments to the identity predicate that vary across worlds.

This book defends a novel view of mental representation—of how, as thinkers, we represent the world as being. The book serves as a response to two problems in the philosophy of mind. One is the problem of first-personal, or egocentric, belief: how can we have truly first personal beliefs—beliefs in which we think about ourselves as ourselves—given that beliefs are supposed to be attitudes towards propositions and that propositions are supposed to have their truth values independent of a perspective? The other problem is how we can think about nonexistents given the widespread view that thought essentially involves a relation between a thinker and whatever is being thought about. The standard responses to this puzzle are either to deny that thought is essentially relational or to insist that it is possible to stand in relations to nonexistents. This book offers an error theory to the problem. The responses from this book arise from the same commitment: a commitment to treating talk of propositions—as the things towards which our beliefs are attitudes—as talk of entities that actually exist and that play a constitutive and explanatory role in the activity of thought.

Perdurantists hold that we persons—just like other ordinary objects—persist by perduring, by having temporal parts, or stages, located over time. Perdurantists also standardly endorse the B-theory of time. And, in light of this endorsement, they typically characterize our tensed beliefs as self-ascriptions of properties, made not by us but by our stages. For instance, for me to believe that Angela Merkel is currently the chancellor of Germany is for my now-located stage to self-ascribe the property of being simultaneous with Merkel’s chancellorship. The problem with this way of understanding tensed belief is that it undermines—if not outright contradicts—the perdurantist’s best options for resisting the Too Many Thinkers objection. In what follows, I show why this is. I then consider what I take to be the perdurantist’s most promising alternative account of tensed belief. I argue that this alternative either leaves perdurantists no better off with respect to the Too Many Thinkers objection or, instead, leaves them vulnerable to another objection, one that they would otherwise have no problem resisting.