NoR 2.3b: That (and those).

This is one of a series of posts setting out my work on the Nature of Representation. You can view the whole series by following this link

In the last post, I outlined the account Dickie develops of the cognitive architecture of perceptual demonstrative thoughts. In her telling, a linked “file” or “body” of belief is built up, associated with a perceptual link to a particular object O, and the information that arrives from that perceptual link has a privileged role in the maintenance of the file of information over time (it is the body of beliefs “proprietary” means of justification, in Dickie’s phase).

Now, from the perspective of radical interpretation, the question to be asked is: what assignment of reference to the perceptual demonstrative “that” that figures in each of these beliefs will make the subject overall most rational? And we’re assuming here that what’s at issue is finding an interpretation of the agent that’s most justification-maximizing. This is also Dickie’s view and her explicit project: her book is in large part an examination of how a “Reference and Justification” principle can explain the things that people have wanted to say (or improve those things) for a variety of kinds of singular thought, including perceptual demonstratives. Here is her formulation, lightly edited:

  • A body of ordinary [a is F] beliefs are about object O iff for all [F], if S has proprietary rationality-securing justification for the belief [A is F], this justification eliminates every rationally relevant circumstance where O is not F.

In the case of perceptual demonstratives, what this tells us is that the referent of demonstrative concept [A] is O iff the fact the [A is F] are canonically formed through the perceptual link justifies a belief that O is F (with a certain relevant-alternatives model of justification presupposed).

Here’s one thing I want to emphasize from the get go. The interpretation of the general concepts (which properties they denote) is presupposed in Dickie’s principle–that a concept [F] denotes property F is a fact about content that we don’t get by free just by giving the concept a suggestive label. The question Dickie’s principle addresses is this: among interpretations which hold fixed predictive content, what favours one assignment of singular content over others? That makes it different from the questions addressed in our discussion of conjunction and quantification, where our predictions were never contingent on the content of other elements of our conceptual scheme. So even if we can explain using Dickie’s principle what object a perceptual demonstrative denotes, that still won’t explain why the demonstrative denotes that object, since interpretations which assign some other singular content, but also tweak the interpretation of general content, remain uneliminated. I’ll come back to this later. But for now, I hope it’s clear that a background of radical interpretation makes excellent sense of Dickie’s project, even if it’s not the background for it she herself has in mind (she thinks one can derive Reference and Justification from first principles concerning the nature of Truth and Reference and Truth and Justification, rather than having to rely on a speculative global metaphysics of content).

The best way to cause trouble for the Reference and Justification puzzle is to question whether the object at the far end of the perceptual link is the unique way to rationalize the file-management practices the agent has in place. Those including forming beliefs which (in ordinary circumstances) will match the observable properties possessed by the object O at the far end of the link. The hardest cases will be when we have deviant candidate referent O* of the demonstrative concept whose observable properties reliably match those of O, for then the body of beliefs will be reliable if interpreted as concerning O* just as much as O. (In other cases, citing the lack of reliability of the file-management practices should be sufficient to defend the needed epistemological claim).

Let’s take Woody the tree as a plausible candidate referent of our perceptual demonstrative d. Problem cases fall into two kinds:

  • Non-natural objects closely related to Woody.
  • Natural objects not closely related to Woody, but whose properties match Woody’s.

Let me take the the second of these first. There are, perhaps, many trees very like Woody. We can imagine that (by coincidence) many of the perceptual beliefs that we in fact form would be true if the demonstrative were interpreted to be about one of these other trees. But truth of beliefs is one thing; justification is another. It’s pretty clear that forming beliefs about the detailed observational properties of some tree in Ireland, on the basis of a perceptual link to Woody, would be unjustified. It wouldn’t even tend to be a reliable method.

But there are more recherche possibilities where such a method of belief-formation would be reliable. Suppose (riffing on a theme from Strawson) that our sector of the universe has an exact duplicate elsewhere in space-time. We may even suppose that it is a consequence of the laws of nature that the universe has some mirror symmetry in space, or translational symmetry in time. Because it is a matter of law that Woody’s properties match those of his counterparts in another sector, forming beliefs about the properties of Woody’s counterpart on the basis of a perceptual link to Woody is reliable. Dickie’s response to such a case would be to insist that reliability in this sense isn’t sufficient for justification, and such beliefs, were they formed, would be unreliable (of course, if one were justified in believing one lived in a symmetrical universe like this, justification for such beliefs may be available, but such beliefs would be inferential, not immediately formed via the perceptual link).

(Here’s my reconstruction of Dickie’s account of the case at pp. 66-68. Key to it is a model according to which a belief is justified if it is true throughout all the “rationally relevant circumstances” which are not eliminated by our evidence. Dickie argues that the rationally relevant circumstances will include those where massive reduplication occurs, and those where it doesn’t (it isn’t limited, then, to whatever the nomic possibilities happen to be, if those enforce symmetry). She further argues that our evidence—our local causal interaction with pieces of our environment—won’t discriminate between worlds which agree on how things are in our local sector. Let’s suppose that the relevant belief is that Woody is large. By the first premise, for every world in which Woody has a twin in another sector which is (a macroscopic duplicate and so) large, there is another world in which that twin is not large. By the second premise, our evidence either eliminates both or neither of such a pair of possibilities. We now argue by cases. If in at least one such case the evidence eliminates neither, then the evidence doesn’t justify the belief that Woody’s twin is large, so that would (to that extent) be an uncharitable interpretation of the demonstrative belief. If on the other hand our evidence suffices to eliminate all such pairs of worlds, that it would en passant eliminate all the world’s where Woody’s twin is large. So again, the belief that Woody’s twin is large wouldn’t be justified. Either way, the beliefs attribute by the deviant twin-ascribing interpretation would be unjustified.)

The more serious threat to uniqueness arises from non-natural objects in the vicinity of Woody. Here are some examples: the shell of material that constitutes Woody’s outer surface. Today’s time-slice of Woody. The mereological fusion of Woody with a bug sitting on a leaf that is hidden from view. Woody himself is a “naturally unified” object, a material substance. None of the candidates that I’ve mentioned can claim this dignity. But nothing in what I’ve said so far accounts for why that should matter. The outer shell of Woody has the same distribution of coloured surfaces in space as Woody, and its observable trajectory through space coincides with Woody’s. The same goes for the present time-slice, throughout the period where we’re tracking Woody. The fusion of Woody with the bug differs, but only in minor ways that we do not discriminate, given our perspective on Woody. Any of these referents would make the beliefs we form through the perceptual link true.

But a belief can be true though formed through an unreliable method, and even reliability doesn’t guarantee justification. Consider Woody’s time-slice as candidate referent. Suppose our perceptual demonstrative “file” is opened at 12pm on Monday, and closed (the link is broken) five minutes later. The practice of allowing information from the link to override other sources of information tracks both the properties of Woody, and of Woody’s Monday time-slice, during that period. But the file-management techniques that are being deployed not sensitive to time elapsed. Had the file remained open, the file would have received information corresponding to how Woody was on Tuesday—but Woody’s Monday-slice would have no observable properties at that time. In a sense, the point here is similar to that made about unrestricted quantification. The epistemological structure doesn’t build in any sensitivity to the duration over which the file has been open, and so an interpretation which makes the beliefs so formed reliable only so long as not too much time has elapsed looks like it attributes epistemically riskier beliefs than the alternative. So this particular non-natural object I think can be ruled out.

We might try something similar to handle the bug problem. We can’t see the bug from our perspective, but the file management structure is such that were we to move in and examine Woody with care, we’d form beliefs about the location of the thing  which would track Woody’s properties, and not those of the fusion of Woody and the bug.

But not all candidate referents can be ruled out in this fashion. The outer shell of Woody is indiscriminable from Woody, observationally speaking. (Or at least, I assume so. Dickie at one point suggests that our visual systems attribute solidity to the objects we see, and that an outer shell would not have this property. I find that surprising: it doesn’t seem to me that we are suffering a perceptual illusion of solidity when viewing a football or a hollow tree). Variants of the bug case can do similar work. Some bugs that are definitely not part of Woody are too small for us ever to observe unaided (through our standard perceptual links), and so prima facie the file-management structures would work very nicely to provide justified beliefs Woody+bug and other “microscopic variants” of Woody. The account, if it aims to secure determinate reference to Woody, suffers from a bug bug. We should distinguish the bug bug from what Dickie calls the intentional problem of the many. The latter case concerns “atomic trees”, i.e. fusions of atoms in Woody’s vicinity, massively mereologically overlapping Woody himself. Such cases are constructed to be ones where it’s not clear that the cited objects are distinct from Woody (it’s not clear that they’re not all trees), whereas the bug bug focuses on something we agree is not a tree, and asks how and why and whether we lock onto the tree itself.

Now perhaps Dickie would want to push the project of securing determinate reference to the natural unities here—the tree rather than the shell or tree+bug. If she can achieve it (without adding new ad hoc principles) I can borrow her work. On another day, I might pitch in to try to help her secure this result.

But for today, I don’t think for my purposes it matters much whether we can narrow down the reference further or not. I can simply concede that the bare perceptual demonstratives are indeterminate in reference between all these natural and less natural objects located at the far end of the perceptual link, which share all the observational properties. This does mean giving up the claim that bare perceptual demonstratives by default lock on to natural unities or ordinary objects of familiar kinds. That might be a disappointment for some, but it doesn’t seem an implausible point at which to end up.

Let me be clear: what I’m proposing is the bare architecture we’ve been discussing so far doesn’t explain how we secure determinate reference to natural unities. I’m not saying determinate demonstrative reference to such things is impossible. The bare story, I think, is really better equipped to explain the semantic value of a slight syntactic variation of the concept we’ve been considering, viz. the bare demonstrative plural those, which determinately refers plurally to all the objects at the far end of the perceptual link which are macroscopic duplicates of one another (including Woody). But even if the bare perceptual demonstrative can only secure determinate plural reference, it can still be part of what explains how determinate demonstrative reference overall gets established, via a combination of descriptive and demonstrative material. For example, we might analyze the complex demonstrative “that tree” as follows:

  • The tree which is among those.

This concept determinately picks out Woody, since all the other candidates are not trees. Of course, this complex concept presupposes not just a content for a bare plural perceptual demonstrative, but also for the general concepts “tree”, “among” and the determiner “the”. But remember: Dickie’s story already presupposed fixed content for general concepts (in her case, observational properties).

More generally, we are not here trying to construct a reductive metaphysics of meaning (that was already given by the general formulation of radical interpretation) but to draw out predictions of that story. So there’s no need for the stories we offer for this or that concept to fit together some reductive hierarchy.

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