So I was given a replacement computer now until the other one arrives. If you're waiting for a sign of life from me, I'll probably contact you soon.
But first some philosophy. I want to argue that necessitarianism is compatible with Humean recombinatorialism because powers aren't intrinsic in the sense relevant to this. I also want to suggest that in an ontology of powers, what's fundamental aren't really the powers, but the causal or nomic relations.
Necessitarianism is the view that properties like mass and spin have their causal or nomic role essentially: if a property doesn't behave like mass, it isn't mass. It follows that the laws about mass are metaphysically necessary. (There are many different views in the vicinity here, maybe more about this later.)
I've just arrived in Canberra, where I'm visiting the ANU for a little while.
To be an electron is to roughly satisfy our electron theory;
to be a banana is to roughly satisfy our banana theory. To say
that electrons or bananas are such-and-such is equivalent to saying
that things (roughly) satisfying a certain theoretical role are
such-and-such.
Thus our Total Theory of the world is arguably a priori equivalent
to its "electron" ramsification or its "banana" ramsification, in
which all occurrences of "electron" and "banana", respectively, have
been replaced by existentially bound variables. What Total Theory adds
to those Ramsey sentences is only the Carnap sentence for "electron"
and "banana": the material conditional with the Ramsey sentence in the
antecedent and Total Theory in the consequent. And this conditional is
arguably analytic.
Lots of interesting stuff came up at the Summer School and the GAP and the A Priori workshop. Here's just two quick notes on something Jason Stanley mentioned in his talk on "Knowledge and Certainty".
Jason argued that knowledge does not entail certainty. He pointed out that in Unger's arguments to the opposite conclusion, "know" is always emphasized, as in:
Oh dear, I just came back from the summer school with David Chalmers in Cologne, and it looks like some mysterious event has yesterday reset my server to August 30. This means that if you've sent me an email during the last 6 days, it hasn't reached me: please re-send. Any weblog comments from this time are also lost (I've recovered the earlier ones from my feed reader.), and the same goes for the new anti-comment spam system I set up before I left and, ironically, the backup system I had only half finished.
Here's an odd passage from Armstrong's A Combinatorial Theory of Possibility, p.116:
[Hume's Distinct Existences Principle], as we shall uphold it, may be stated thus:
If A and B are wholly distinct existences, then it is possible for A to exist while no part of B does (and vice versa).
The principle applies straightforwardly to individuals, properties and relations. [...]
It is interesting to notice that the converse of Hume's principle also seems to be true:
Robbie has some interesting posts about rigidity. That made me wonder about "the actual number of planets", which no longer denotes the number 9 now that Pluto doesn't count as a planet any more. So what should we say?
- "TANOP" rigidly denoted the number 9 last year and rigidly denotes the number 8 this year. (-- Even though the astronomical facts haven't changed in any relevant way!)
- "TANOP" always rigidly denoted the number 8. (-- So Quine was wrong, but not because he got the astronomical facts wrong, but because he didn't know what he meant by "planet"; in fact, til last week, nobody ever knew what they meant by "planet"!)
- "TANOP" changed its meaning in 2006. (-- So when we say that the number of planets is 8 we don't disagree with Quine when he said that the number of planets was 9!)
I think the third option is the only credible one. Would people with sympathies for reference magnetism go for the second? (If you would, do you think it's possible that the members of the IAU, who voted about the new definition last week, might have got the definition wrong?)
*) Oskar Minkowski discovered that dogs whose pancreas is removed develop the symptoms of diabetes.
Suppose this is the first time you've heard the name "Oskar Minkowski". Cases like this are good candidates for causal descriptivism. According to causal descriptivism, my utterance of (*) is true iff there is a person standing at the origin of a certain chain of communication leading to my present use of "Oskar Minkowski", and this person discovered that dogs whose pancreas is removed develop the symptoms of diabetes. This comes close to many people's intuitions about possible cases.
In July, I tried to show that Williamson's argument against luminosity fails
for states that satisfy a certain infallibility condition. I now think that (for basically the same reason) Williamson's argument fails for any state whatsoever, including knowing something and being such that it's raining outside. (The latter of course isn't luminous, but this is not established by
Williamson's argument.)
In their contributions to Lewisian Themes, Rae Langton and Jonathan Schaffer both argue that quidditism -- the claim that possible worlds may differ only in which intrinsic properties play which causal/nomological roles -- does not entail skepticism about intrinsic natures because standard replies to skepticism about the external world carry over to skepticism about intrinsic natures.
But it seems to me that there is an important difference: if quidditism is true, we not only lack knowledge about intrinsic natures, but also any beliefs about them.