Wolfgang Schwarz

Trouble with Centered Worlds

I would like to say that

If X necessarily entails all truths, and if X's A-intension coincides with its C-intension, then X a priori entails all truths.

For suppose X -> P is not a priori for some truth P. Then X -> P is an a posteriori necessity. So we need information about the actual world to know what C-intension X -> P expresses, and whether it is true. But by assumption, this information is already contained in X, and since X's C-intension coincides with its A-intension, it cannot be hidden away in X so that we'd need further information to find out that X contains that information. Hence X a priori entails X -> P; and so X -> P is itself a priori.

Thanks, yes, I'm fine

It's just been rather cold here for the last few weeks, so I've spent most of my free time in cafes, writing a lengthy paper on the semantics of attitude reports. (I'll post it when it's reached Draft status.) In addition, the OS on my desktop computer is really broken right now. I guess I'll have to switch to something that works.

Making a Difference

This argument looks a lot better than it is:

Suppose some physical event E is causally necessitated by a certain distribution of physical properties P. Then if P occurs, E is bound to occur as well, no matter what else is the case. In particular, whether or not some non-physical event M also occurs before E will make no difference to E's occurrence. (Perhaps M nevertheless causes E, if E is overdetermined, or perhaps M is causally relevant in some even weaker sense, but at any rate M does not make a difference for E.)

To see the problem with this argument, consider a deterministic world where the occurrence of any event E at time t0 is causally necessitated by the state of the world at t-2 (before t): it obviously does not follow that the state of that world at t-1 makes no difference to E's occurrence.

Moorean Facts About Knowledge

For some reason, I find Moore's refutation of idealism ("here is a hand; therefore there is an external world") much more convincing than his refutation of skepticism ("I know that here is a hand; therefore I know that I am not a brain in a vat".) Why is that?

In both cases, Moore's argument would not convince his opponent who would obviously reject Moore's premise. So that's not the difference. I think the difference also isn't that skepticism is a philosophically stronger position than idealism. Rather, it seems to me that the premise against idealism is much more certain than the anti-skeptical premise. That here is a hand (or at least that there are hands) is about as certain as non-logical truths get, that I know that here is a hand is not. If I were to compile a list of Moorean facts -- of facts that are at least as certain as any philosophical argument against them --, I would include all kinds of facts about material objects, other people, experiences, mathematics and modality, but knowledge claims probably wouldn't make the list.

Lewisian Meaning Without Naturalness

Here's a draft of a paper I wrote in the mountains, mainly summarizing a few old blog entries: Lewisian Meaning Without Naturalness (PDF).

Trust and Dyadic Conventions

I had another look at Lewis's trust condition on linguistic conventions. It says that the members of a linguistic community generally take utterances of a sentence as evidence that the sentence is true. My opinion up to now has been that insofar as this condition is correct, it is redundant, and insofar as it is not redundant, it is incorrect.

The condition seems mostly redundant because the convention of truthfulness already requires of everyone to impute truthfulness to others. To be truthful means to try to utter sentences only when they are true. So by partaking in the convention of truthfulness in English, I already expect you to utter "it's raining" only when you believe that it's raining. So unless I believe your opinions about the weather are unreliable, I will take your utterance as evidence for rain. No need for an additional convention of trust.

Back (obligatory Umsu picture)

Away

I'm away in the mountains (without internet access) for about a weak. Happy Christmas, Hanukkah, Kwanzaa or whatever else you celebrate, and Happy Ordinary Days if you don't celebrate anything.

Structural Magnitudes?

The fundamental properties provide a minimal basis for all intrinsic qualities of things. That is, whenever two things are not perfect qualitative duplicates, they differ in the distribution of fundamental properties over their parts; whenever two things do not differ by that distribution, they are perfect qualitative duplicates. It follows that all fundamental properties are intrinsic. But not all intrinsic properties are fundamental: the fundamental properties provide a minimal basis for all qualitaties. Hence there is no fundamental property of having a mass of either 1g or 2g, because instantiation of that property is already determined by the distribution of mass 1g and mass 2g. For the same reason, there is no fundamental property of being the fusion of a round thing and a distinct rectangular thing. By and large, fundamental properties are never logically complex (like A or B) and never structural (determined by the distribution of properties over the parts of their instances).

Shared reference without descriptive knowledge

In August, I posted an argument purportedly showing that if it is common knowledge within a linguistic community that everyone refers to the same thing by some name N, then the descriptions individuals associate with that name can only differ for very remote possibilities. The argument went like this:

If we know something, it holds in all possible situations that might, for all we know, be actual. So if we know that our terms corefer, they do corefer in all situations that might, for all we know, be actual. And if I know that you know that our terms corefer, they do also corefer in all situations that might, for all I know, be situations that might, for all you know, be actual. And if I know that you know that I know that our terms corefer, they do also corefer in situations I believe you might believe I might believe to be actual. And so on. In conclusion, our terms corefer in all situations that have some chance of being believed (or believed to be believed, etc.) to be actual in our community. So if we consider the corresponding functions from possible situations to extensions, our idiosyncratic functions will only differ for quite remote possibilities.

There must be something wrong with this argument, for its conclusion is false. Suppose the description you associate with "quicksand" is "a bed of loose sand mixed with water forming a soft shifting mass that yields easily to pressure and tends to engulf any object resting on its surface", whereas what I associate with the term is "what you call 'quicksand'". Suppose also it is common knowledge between us that that's the description I associate. So it is common knowledge between us that our descriptions pick out the same stuff. But clearly, I do not know what kind of phenomenon "quicksand" refers to. That's why I don't know how to behave when you tell me that there's quicksand nearby. For all I know, you could be telling me that there's watery stuff nearby (and mean watery stuff by "quicksand") or that there are houses nearby (and mean houses by "quicksand"), and so on.