Necessarily coextensive, yet distinct?

So here’s an Aristotelian puzzle that I do not know how to sort out. It has apparently been reinstated, or a version of it, by Fine. I believe he did not even present it as a puzzle. Anyway, take a look at it, and help me solve it. Otherwise, I’m lost (and so is my paper).

Suppose you believe that properties are the set of their instances. Suppose, furthermore, that you are a modal realist. Aristotle was not, but he does believe in potential and actual bearers of properties, and he does think these are within the extension of a property [Meta, V.26].

In any case, there is a familiar problem with this view: coextensive properties. ‘renate’ and ‘chordate’ have the same actual extension, yet they are different properties. The solution is easy and well known: ‘renate’ and ‘chordate’ are not coextensive because they have different extensions in other possible worlds. Aristotle’s reply would be similar: ‘renate’ and ‘chordate’ are not coextensive because they have different potential instances.

The problem comes with a twisted version of this objection. Suppose you have necessarily coextensive properties, and yet distinct ones. (This is what Fine presents in his ‘famous’ paper against modal accounts of ‘essence’, where he claims ‘essential property’ is not synoymous with ‘necessary property’, I think, however, that Aristotle’s example is better). Aristotle talks about ‘Grammarian’ and ‘Human’. According to Aristotle, this much is true:x is human iff x is a grammarian (or has knowledge of grammar). Yet, ‘Human’ reveals the essence of its instances, and ‘grammarian’ does not.

My question is this: is there any way in which one can sort this case out, and still be extensionalist about properties? Do you know of any extensionalist reply to this? Or should we simply claim that ‘grammarian’ and ‘human’ have the same meaning?

How to Be an Instrumentally Rational One-Boxer

I’ve been thinking about Newcomb’s Paradox lately and find myself strongly inclined towards one-boxing. Because there are so many interesting and complicated issues looming in the background, perhaps I’ll change my mind at some point. In any case, my goal in this post is not to convince anyone to be a one-boxer but only to defend the claim that one can indeed be an instrumentally rational one-boxer. The defense, I should warn, is exceedingly simple. But simplicity has things to be said for it.

The Defense

Finding myself in the Newcomb room and in a greedy state of mind, I would recognize that I occupy one of the following four worlds (provided that I play the game, that the game is as it was described to me, and so forth), which are ordered according to my preferences:

(W₁) Predicted 1; Taken 2; Payoff $1,001,000
(W₂) Predicted 1; Taken 1; Payoff $1,000,000
(W₃) Predicted 2; Taken 2; Payoff $1,000
(W₄) Predicted 2; Taken 1; Payoff $0

Peter van Inwagen on Clifford’s Principle

While preparing for the philosophy of religion course I’m teach this summer, I just came across Peter van Inwagen’s essay “Quam Dilecta”. The essay appears in God and the Philosophers (1994, Thomas Morris, ed.), a collection of autobiographical essays where the authors (professional philosophers of varying distinction) explain

how they personally see the relationship between the spiritual and the philosophical in their own lives, or else [show] with their own stories how a person of faith can grapple with some of the problems and prospects of religious belief from a philosophical point of view. (p. 4)

At the end of his essay, van Inwagen presents his reasons for trusting “the Church” rather than “the Enlightenment”. There is much (much) one could say about these reasons, but, there is no need to, since van Inwagen himself admits that he believes what he does on the basis of “insufficient evidence”. However, prior to giving his (insufficient) reasons for “trusting the Church”, van Inwagen dedicates a section of his essay to explaining why he rejects the demand for sufficient evidence. This is the section of his essay I’d like to say just a little about here.

PNRG online

Publicity:
Some of you might not know that some of us have organized the PNRG (Proper Names Reading Group). The PNRG is intended to get all the pro-language enthusiasts together. Our plan is to read one paper a week, and discuss its content by means of the comments given by one of us. Last week Dustin Tucker commented on Kroon’s “Causal Descriptivism”, and the first week I commented Braun’s introductory paper “Proper Names and Natural Kind Terms”. Next week, Thursday 24th, we will learn from Mike’s comments of Stanley’s “Names and Rigid Designators”. We meet every Thursday (except this week), 5-7, Seminar Room. If you are interested and want to glance at the reading list, drop me a line.

Philosophy:
Enough publicity.
In my complementary comments to Braun I dared to argue that the four problems of Millianism (as Braun presents them) really boil down to two. As it turned out, I found that the claims were stronger than the argumentative support I was then giving. Jason Konek and Jon Shaheen pointed this out. They argued against the idea that the so-called “problem of informativeness” could be reduced to the problem of belief ascriptions. Jason exemplified his claim by referring to Eric Swanson’s ‘presupposition’ solution to the problem of informativeness, which, he said, is independent from his solution to the problem of belief ascription. Jon argued differently. He said that the problem of informativeness could be accounted for without appealing to mental states, and so without solving the problem of belief ascription. I still think that any good solution to one of the informativeness-belief-ascription dyad is a good solution to the other.

In this post I want to present Eric Swanson’s claims about these issues. I will argue against Jason that (1) Swanson’s treatment of the puzzles makes it even clearer to see why a solution to informativeness is a solution to belief ascription (and vice versa): and exemplify against Jon that (2) you cannot solve informativeness problems without appealing to mental states.