The metaphysics of quantities

I've long been puzzled by the nature of quantities, but I've never really followed the literature. Now I've read Jo Wolff's splendid monograph on the topic. I'm still puzzled, but at least my puzzlement is a little better informed.

The basic puzzle is simple and probably familiar. On the one hand, being 2m high or having a mass of 2kg appear to be paradigm examples of simple, intrinsic properties. On the other hand, these properties seem to stand in mysterious relationships to other properties of the same kind. First, there's an exclusion relationship: nothing can have a mass of both 2kg and 3kg. Second, there are non-arbitrary orderings and numerical comparisons: one thing may be four times as massive as another; the mass difference between x and y may be twice that between z and w. If 2kg and 8kg are primitive properties, why couldn't an object have both, and where does their quasi-numerical order and structure come from?

Ability, control, and chance

In my paper "Ability and Possibility", I argued that ability statements should be analysed as simple possibility modals: 'S can phi' is true iff S phis at some world compatible with relevant circumstances.

This view is widely considered inadequate because it seems to violate two (related) intuitions about ability.

One is that ability requires a kind of robustness: if you have the ability to phi, then you reliably phi whenever the need arises, under a variety of circumstances.

Epistemic luck

I've been teaching a course on classical epistemology this term, so I've thought a little about knowledge.

A common judgement in the literature seems to be that knowledge is incompatible with a certain kind of luck -- the kind of luck we find in Gettier cases. This is then cashed out in terms of safety: for a belief to constitute knowledge it must be true in all nearby possible worlds.

While I share the initial judgement, the development in terms of safety doesn't look plausible to me. It has the wrong kind of structure.

For example, any true belief that concerns a modally robust subject matter is automatically safe. But such beliefs are not immune from Gettier cases. I'm sure one can find examples where, say, Newton's laws are used to predict whether two asteroids will collide, and the laws happen to give the correct answer ('no'), but they don't predict the correct trajectories; the true reason why the asteroids won't collide involves some feature of general relativity. Now if someone in the mid 19th century asked whether the asteroids will collide, and they used Newton's laws to figure out the answer, then their belief (that the asteroids won't collide) is justified and true, but it isn't knowledge. And yet it is arguably true in all nearby worlds.

Reversible Sobel Sequences

A Sobel sequence is a sequence of conditionals with increasingly strong antecedent. Lewis used Sobel sequences to motivate his "variably strict" analysis of counterfactuals.

For example, intuitively (1) and (2) might both be true, which seems to contradict a simple strict analysis:

(1) If the US had destroyed its nuclear weapons in 1965, there would have been war.
(2) If every country destroyed its nuclear weapons in 1965, there would have been peace.

A problem with this argument (pointed out in von Fintel 2001), is that the intuition about (1) and (2) depends on the order in which the sentences are considered. If we consider (2) first, and judge that it is true, then (1) looks at best doubtful.

Newly published: "Objects of Choice"

My "Objects of Choice" paper has now appeared in Mind.

The paper asks how we should understand an agent's decision-theoretic options. That is, what are the things whose expected utility we are supposed to maximize? I think the question is a lot harder than often assumed. For example, I argue that it won't do to say that the options are certain "willings" or "intentions", as some authors have suggested.

In many respects, the problem of options mirrors the "input problem" for Bayesianism: what are the propositions on which rational agents are supposed to conditionalise (or Jeffrey-conditionalise)?

On revisionist reporting

Friends of singular thought typically assume that in order to have a singular attitude towards an object, one must either stand in a special acquaintance relation to the object, or have a special kind of mental representation for it. Both of these views face a challenge from our practice of attitude reports: we can seemingly attribute attitudes with singular content even if neither condition is satisfied.

In a well-known example from Sosa 1970, the army generals decide that the shortest man should go first. The Sergeant tells Shorty: 'they want you to go first'. Here the generals need not be acquainted with Shorty, and it is doubtful that they must have a "mental file" for him.

Epistemic counterparts 7: Distributed plural roles

So far, we have looked at cases in which an agent has a descriptive belief (e.g., "the creature approaching through the woods is a bear"), which gets reported as a singular belief ("Mary beliefs Mark is a bear"). But sometimes we attribute singular beliefs even though the subject appears to have only a general (quantified) attitude about the relevant individual.

A murder has been committed. The detective has figured out that the culprit probably comes from a certain mountain village. She knows little about that village, but believes that all its inhabitants are poor peasants. You are one of the villagers. We might say:

Dispositions, intrinsicality, and the problem of fit

In chapter 3 of The Powers Metaphysic, Neil Williams presents a nice problem for dispositionalists: the "problem of fit".

Dispositionalists hold that there are fundamental dispositional properties. Now consider a particular rock and a particular glass. The rock might have a disposition to break the glass when thrown at it. And the glass might have a disposition to survive impact of the rock. These dispositions are incompatible: if the rock is disposed to break the glass, the glass can't be disposed to survive the impact. But if dispositions are fundamental, then what prevents the rock and the glass from having the incompatible dispositions? The dispositionalist seems to require a mysterious ban on recombination.

Epistemic counterparts 6: De re/de dicto equivalence

Compare the following three sentences.

(1) I thought my husband was a bear.
(2) Mary thinks her husband is a bear.
(3) I think my husband is a bear.

(1) and (2) are ambiguous between a "de re" reading and a "de dicto" reading. But (3) only seems to have the "de dicto" reading. How come?

According to the semantics I have described in earlier parts of this series, an utterance of (3) is true on its de re reading iff (roughly) there is a suitable role R such that (i) in all the speaker's belief worlds, whatever plays R is a bear, and (ii) in the actual world, the speaker's husband plays R.

Lewis's Nihil Obstat

The latest issue of The Monist contains an outline of an unpublished paper by Lewis: "Nihil Obstat: An Analysis of Ability", along with a useful commentary by Helen Beebee, Maria Svedberg, and Ann Whittle.

Lewis's analysis of ability goes as follows:

You're able to φ iff, for some basic action
(1) doing it would be φing, and
(2) there is no obstacle to doing it.

It is clear from this analysis, and from the context in which it is presented, that Lewis is only interested in a rather specific sense of 'ability'. He wants to spell out the sense in which we are able to perform particular intentional actions that we don't actually perform, even if the world is deterministic. He is not interested in our ability to regrow injured skin, or in the ability of tardigrades and steel to withstand high temperatures. He also isn't interested in what are sometimes called "general abilities", like my ability to play the piano that I have even when I don't have access to a piano. (At any rate, this kind of ability is not covered by his analysis, and it isn't relevant to compatibilism.)

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