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Soames on the Contingent A Priori

Saul Kripke famously argued that some propositions are both contingent and knowable a priori. For instance, one who introduces the term ‘one meter’ as a rigid designator for the length of a certain stick s at time t is meant to be in a position to know a priori that if s exists at t then the length of s at t is one meter. Call this the meter proposition. Scott Soames (2003) says that neither the meter proposition nor any of Kripke’s other examples are genuine examples of a priori contingencies. Soames observes that the baptizer’s knowledge of the meter proposition would have to be based partly on the knowledge that the term ‘one meter’ refers in his language to the length of an object iff the length of that object is one meter. Call this further proposition the R-proposition. The question of whether the meter proposition is known a priori therefore turns on the question of whether the R-proposition is known a priori. Soames offers the following reason for denying that the R-proposition and related propositions can be known a priori: “If they could be so known, then non-English speakers should be able to know them simply by reflecting on and reasoning about them—which of course they cannot.” (2003,408-9)

Soames does, however, admit that there are genuine a priori contingencies, for instance, that if actually Princeton has a philosophy department then Princeton has a philosophy department. Call this the Princeton proposition. The argument for the contingency of the Princeton proposition is straightforward: Its antecedent will be true at all worlds—since it is true at all worlds that in our world Princeton has a philosophy department—including those worlds in which Princeton has no philosophy department. At such worlds, the conditional as a whole is false; hence, the Princeton proposition is contingent. The argument for its a priority is equally straightforward, for one can know a priori, of any proposition that one entertains, that it is true iff true in one’s own world.

I’m going to argue that Soames’s stated reason for denying that the R-proposition can be known a priori should be rejected on the grounds that it’s equally a reason for denying that the Princeton proposition can be known a priori. So Soames’s argument against the a priority of the meter proposition fails. And this isn’t merely an ad hominem attack, for it is widely assumed that such propositions as the R-proposition cannot be known a priori, yet it is difficult to find (or imagine) any reason for assuming this other than the one Soames supplies. So unless there is some flaw in the reasoning behind the a priority of the Princeton proposition (and there isn’t), we are left with no satisfactory reason for supposing these semantic facts to be knowable only a posteriori.

Soames seems to have in mind something like the following argument in the passage quoted above (I’ve added some charitable bells and whistles):

(P1) A proposition p can be known a priori only if, necessarily, if p is true then anyone who understands p and is suitably intelligent can come to know p simply by reflecting on and reasoning about it.   
(P2) The R-proposition is true and some suitably intelligent individuals understand it but cannot know it simply by reflecting on and reasoning about it.
(C) So the R-proposition cannot be known a priori.

The reasoning behind P2 is straightforward: just as non-French speakers can understand the proposition that the term ‘un pouce’ refers in French to the length of an object iff the length of that object is one meter without being in any position to know whether it is true or false, non-English speakers can understand the R-proposition perfectly well without being in any position to know whether it is true or false.

But P1, together with the following premise P2*, entails that the Princeton proposition cannot be known a priori:

(P2*) Possibly, the Princeton proposition is true and some individuals understand it and are suitably intelligent but cannot know it simply by reflecting on and reasoning about it.

The possible individuals in question will be inhabitants of a world other than our own in which Princeton has a philosophy department. In order for them to understand the Princeton proposition—which is, at least in part, a proposition about our world—they have to be able to think about our world. Singling out a specific nonactual world in thought is no small feat, but we may suppose that their mental capacities far exceed our own and that they are able to get our world uniquely in mind by imagining it in full detail. They nevertheless will not be in a position to know the Princeton proposition simply by reflecting on and reasoning about it. For although they can know that its antecedent (which is true in their world iff Princeton has a philosophy department in our world) is true simply by reflecting on and reasoning about it, they cannot know that its consequent (which is true in their world iff Princeton has a philosophy department in their world) is true simply by reflecting on and reasoning about it. Consequently, they cannot know whether the conditional itself is true simply by reflecting on and reasoning about it.

So P2* is true. So either P1 is true, in which case it follows that the Princeton proposition cannot be known a priori, or P1 is false. The Princeton proposition can be known a priori. So P1 is false, Soames’s argument that the meter proposition cannot be known a priori fails, and we lose the standard (and perhaps only) reason for taking R-propositions to be knowable only a posteriori.

Borderline Composition without Metaphysical Vagueness

Ted Sider argues that composition is unrestricted on the grounds that, were it restricted, there’d have to either be sharp cut-offs with respect to composition or borderline cases of composition, and there can’t be either. The conventional wisdom is that embracing borderline composition is going to lead either to metaphysical vagueness or else some sort of relativism. That not quite right: I know of at least four ways (one due to my blogmate Chad Carmichael) to be a non-relativist borderliner without abandoning a linguistic theory of vagueness. I want to sketch one way here. It’s kind of crazy, but not obviously crazier than unrestricted composition.

Some background: numerical sentences are sentences of the following form that say that there are exactly n concrete things (for some number n, in this case 2): ‘∃x∃y(Cx & Cy & x≠y & ∀z(Cz → (x=z v y=z)))’. One premise of Sider’s argument is that whenever there’s borderline composition, some numerical sentence will lack a determinate truth value. After all, it’ll be indeterminate whether there are just some things, or those things *plus* an additional thing that’s composed of them. The strategy I have in mind is to concede that some such sentence lacks a determinate truth value, but insist that the only indeterminacy at issue is semantic indeterminacy. I’ll develop this in three phases. Phase 1: identifying the representational indeterminacy. Phase 2: eliminating everything from the ontology that might lead to nonrepresentational vagueness. Phase 3: ignoring possible objections. 

Phase 1: There are countless perfectly precise ways for simples to be arranged: they may be in arrangement1, arrangement2, arrangement3, and so forth. These are monadic properties, collectively instantiated by pluralities of simples, and each of which has a perfectly determinate extension. The envisaged borderliner will countenance states of affairs involving mereological simples and their precise arrangements. Such states of affairs are all that will be needed for securing the semantic indeterminacy of the numerical sentence. To see why, let us say that some things compose something iff they are arranged objectwise, where the vague expression ‘arranged objectwise’ may be replaced by any vague restriction on composition (e.g., arranged lifewise.) Assuming that some simples cannot compose more than one thing at a time, the numerical sentence for some number n will be true iff the arithmetic sum of the number of simples and the number of sets of simples whose members are arranged objectwise is n. Because it is a vague restriction there will be borderline cases of being arranged objectwise. Suppose that simples in arrangement1 through arrangement10 are the clear cases of being arranged objectwise, and that simples in arrangement11 are a borderline case of being arranged objectwise. The sparse borderline can then say that the numerical sentence for n is semantically indeterminate insofar as it is indeterminate which of the following two (perfectly determinate) states of affairs it represents as obtaining:

(i) There being m simples and n minus m sets of simples who members are either in arrangement1 or arrangement2 or … or arrangement10.

(ii) There being m simples and n minus m sets of simples who members are either in arrangement1 or arrangement2 or … or arrangement10 or arrangement11.

One might naturally think of these states of affairs as precisifications of the numerical sentence for n.

Phase 2:  Linguistic theorists agree that it’s indeterminate whether Paul is bald, but avoid de re vagueness by denying that there is such a property as the property of being bald; there are only the perfectly precise properties: bald1, bald2, bald3, etc. There also is no such proposition as the proposition that Paul is bald (which would be a borderline instance of the property of being true) or such a state of affairs as the state of affairs of Paul’s being bald (which would be a borderline case of the property of obtaining).

Our sparse borderliner piggybacks this strategy: there is no such property as being arranged objectwise; there are just the precise properties of being in arrangement1, etc. There also is no such proposition as the proposition that ∃x∃y(Cx & Cy & x≠y & ∀z(Cz → (x=z v y=z))), and no such state of affairs as the state of affairs of there being an x and a y such that (Cx & Cy & x≠y & ∀z(Cz → (x=z v y=z))). So there is nothing in the ontology that exhibits de re vagueness. Mission accomplished!

Phase 3: What, me worry?

Philosophers of Language: Help!

Consider the following sentences:

(a) ‘Rabbits are animals’ is a true sentence of my language iff rabbits are animals.
(b) The word ‘rabbit’ refers in my language to an object iff that object is a rabbit.

Scott Soames says “The propositions expressed by these sentences are standardly not regarded as capable of being known apriori.” He has an argument for their a posteriority, which I may blog about later. But what I’m wondering is: does anyone know of any other discussions of the epistemic status of such propositions? Or even of other places where someone takes a stand (perhaps without extensive discussion) on their epistemic status?

Also feel free to state any strong feelings you might have about whether they're a priori.

Hawthorne on Strange Communities

John Hawthorne raises the following objection to commonsense views of material objects, on which there are familiar kinds (islands, statues, snowballs) but no strange kinds (incars, gollyswoggles, snowdiscalls):

“Barring a kind of anti-realism that none of us should tolerate, wouldn’t it be remarkable if the lines of reality match the lines that we have words for? The simplest exercises of sociological imagination ought to convince us that the assumption of such a harmony is altogether untoward, since such exercises convince us that it is something of a biological and/or cultural accident that we draw the lines that we do.” (2006, 109).

We “draw the lines that we do” largely as a result of our intuitive judgments about what kinds of things there are, so the suggestion evidently is that it is a biocultural accident that we have the intuitions that we do. Why exactly are we supposed to be convinced of this by “the simplest exercises of sociological imagination”? There are a number of things that Hawthorne might have in mind. Let me mention a couple. 

(1) Surely Hawthorne doesn’t mean to suggest that the mere fact that we’re able to imagine strange communities should convince of this. After all, we can also easily imagine communities who don’t share our intuitions about the multiple-realizability of mental properties, about the moral impermissibility of torturing babies for fun, about the premises of various arguments against commonsense ontology, and so on. Whatever reasons there may be for global skepticism about intuition, the mere imaginability of communities with different intuitions is not one of them.

(2) Perhaps what Hawthorne has in mind is that we can easily imagine the sorts of circumstances that might have led us to draw the lines differently and that, since these circumstances could easily have obtained, we could easily have drawn the lines differently. There are two ways in which this is right, and one way in which this is far from obvious.

First way in which it’s right: We could easily have found it convenient to categorize things differently. We classify things as infants, toddlers, and adolescents. Had our biocultural circumstances been different, we may well have found it convenient to have different categories, e.g., infoddlers (i.e., humans that are infants or toddlers) and toddlescents (i.e., humans that are toddlers or adolescents). But infoddlers and toddlescents aren’t strange things. They’re familiar things, strangely categorized. So this is no problem for the commonsense ontologist. 

Second way in which it’s right: Had biocultural circumstances been different, we may well have found it convenient to make different kinds of things. In that case, there would have been different kinds of artifacts. Perhaps they’d have strange persistence conditions. In that case, we would have had different (and correct!) judgments about which kinds of things there are. But that’s no reason to worry about our judgments about what sorts of artifacts we have in fact made. So, again, this is no problem for the commonsense ontologist.

The sorts of cases that would be problematic for commonsense ontologists involve strange ways of individuating (vs. merely classifying) nonartifacts. Let a supertoddlescent be a strange thing that comes into existence when a child becomes a toddler, ceases to exist when a child becomes an adolescent, and is colocated with the child at all times in between. Intuitively, there are none. Are there possible circumstances in which a whole community has different intuitions about supertoddlescents (setting aside communities who’ve been subjected to philosophy)? I suppose so -- for instance, they could just all be stupid. But it surely is no less easy for there to have been stupid communities with different intuitions about supertoddlescents than for there to be stupid communities with different intuitions about the indiscernibility of identicals, or multiple-realizability, the supervenience of moral facts on natural facts, etc.. So, setting aside idle skepticism about the quality of our present cognitive conditions, this by itself is hardly reason to worry about the reliability of our intuitions about supertoddlescents, moral supervenience, etc.

[[I’m ignoring one further interpretation of Hawthorne: that these exercises in imagination show us that there’s no ontologically significant difference between the strange and familiar things which could account for the existence of the one but not the other. I’ve got a whole paper on this if anyone’s interested.]]

Philosophical Methodology Workshop

UT-Austin will be hosting a 5 day summer school for graduate students on the topic of philosophical methodology. Each day of the workshop will include two or three seminar-style sessions led by faculty. In addition, there may be some number of faculty-led roundtable discussions on such issues as conceptual analysis, intuition, thought experiments, conceivability, reduction, reflective equilibrium, and ontological commitment.

To date, confirmed faculty participants include Julia Driver (Dartmouth), Jeff King (Rutgers), Dan Korman (Illinois), Marc Moffett (Wyoming), Roy Sorenson (Dartmouth), Ernest Sosa (Rutgers), and UT faculty Josh Dever, Mark Sainsbury, and David Sosa.

The workshop will be held August 12-16, 2008. Attendance will be limited to around 10 outside graduate students, the presenters, and UT graduate students and faculty. Interested graduate students are encouraged to apply. The deadline for applications is June 7, 2008. See the workshop homepage for details.