Wolfgang Schwarz

G Filter

I've made the script driving the Lewis tracker available for download here. (I have a couple of further ideas and even half-finished pages for david-lewis.org, but they currently suffer from a lack of time and money. Suggestions about useful content are of course welcome.)

Analyticity

I keep wavering between two different uses of "analytical". This entry is meant to remind me of the difference and of why I should prefer the one over the other.

On the first use, a sentence is analytical if it has a universal A-intension. On the second, a sentence is analytical if one can't understand it unless one believes it (this is what I, unoriginally, proposed last year). The first is the better explication.

What Is It?

It consumes energy and emits electromagnetic radiation. It contains a small wire filament. It is widely used all over the world. It was invented by Heinrich Göbel in 1854, though Americans often attribute its invention to Thomas Edison. What is it?

The electrical light bulb, of course.

But hold on. Is there really something that satisfies these conditions? What kind of thing would this be? It can't be any particular light bulb, say, the one in my bathroom. For this light bulb is used only in my bathroom, not all over the world, and most Americans don't even know that it exists. Nor can it be any other particular material thing. Nor can it be a mental object, something like the idea of a light bulb: ideas don't contain small wire filaments. This alleged thing, the light bulb, is a very strange kind of object. It is not a light bulb (all light bulbs are concrete, particular light bulbs), but like all light bulbs it contains a wire filament, consumes energy and emits electromagnetic radiation. It is is located in time (as it didn't exist before 1854), but presumably not at any particular location in space.

Indifference

I've been assigned some boring administrative work, but that's finished now, I hope. Here are some rough thoughts on indifference and Adam Elga's Dr. Evil paper (PDF).

There are many possible individuals whose mental state is subjectively indistinguishable from my current mental state insofar as they all share my current phenomenal experiences and my (real or quasi-) memories. Some of them inhabit worlds that are exactly as I believe the actual world is, and are located in that world exactly where I believe I am located in the actual world. Others occupy very different places in very different worlds: they are brains in vats or inhabitants of gruesome counterinductive worlds. How should I distribute my credence among all these possibilities?

Those Errors

Oops, last night I exceeded my webspace quota. Apologies for the failures and error messages that this caused all over the place. Please let me know if something is still not working.

A Song

Trying (for some reason) to keep myself busy in the evenings, I've started creating music again. So here, for a change, is a song: "Wie Mohn und Gedächtnis" (Ogg Vorbis format, 5.1 MB).

(In case anyone is interested, the song was created in the excellent Cheesetracker, recorded with Ardour, via Jack, and slightly edited with Audacity. All Free and free.)

What is it Like to be a Set?

I've been invited to this year's German-Italian Colloquium in Analytic Philosophy, for which I've put together some remarks on the philosophy of mathematics: "Emperors, dragons and other mathematicalia" (PDF). I mainly argue that mathematical sentences should be interpreted as quantifications over possibilia. Technically, this isn't really new. Daniel Nolan in particular has made a very similar suggestion (PDF). What hasn't been emphasized enough, I believe, is that this interpretation not only works from a technical point of view, but is quite attractive for various philosophical reasons. (Unlike Nolan, I argue that it isn't a reform, but a faithful interpretation of mathematics.)

What is Quantum Indeterminacy?

What can we say about physical systems when they are not in an eigenstate of a certain property? For instance, what can we say about an electron's x-spin when it is in a superposition of 'up' and 'down'?

We can say that a measurement of the property will (or rather, would) deliver such and such results with such and such probability. Most physicists apparently think that this is more or less all we can say. In particular, they argue that we should not interpret the superposition state as something like "the probability that the electron now actually has x-spin up is 0.5": having x-spin up (or down) requires being in an eigenstate of x-spin, but the electron is in no such eigenstate; thus the electron definitely has neither x-spin up nor x-spin down; it is in a superposition state, and that's all there is.

Objects of Perception

One can think of perception as a relation between states (or acts) and objects, the objects that are perceived. Alternatively, one can think of it a relation between a state and a content, the information acquired or represented in the perception.

Content is something that excludes possibilities. Suppose I have a perception of an elephant standing in front of me. What possibilities are thereby excluded? There are at least two reasonable answers: 1) the exluded possibilities are possibilities where there is no elephant in front of me; 2) the excluded possibilities are possibilities where I do not have that experience. Regarded as sets of possible situations, on the first account, the content of my perception is a set of situations in which there is an elephant in front of me. On the second, it is a set of situations where I have the phenomenal experience I actually have, even if it is caused by evil scientists. (Strictly, "I" need not be me, but can be whatever is in the center of the relevant situation.)

Reference Magnetism

Suppose

1) the facts about use etc. underdetermine the semantic value of term x (to a certain degree).

But

2) the semantic value of x is not underdetermined (to that degree).

Let V1,V2,... be the semantic values between which x is underdetermined, and suppose V2 is in fact the value (or range of values) of x. What is it about V2 that makes it the semantic value? Not 'use etc'. But suppose all obvious candidates like causal facts are part of 'use etc.'. Then the relationship between x and V2 -- let's call it "reference" -- is inscrutable insofar as knowing all ordinary facts about use and causation and so on is not enough to find out that x refers to V2. There must be something over and above all this that privileges V2. Let's say (with Lewis) that V2 is a reference magnet (with respect to x).