Wolfgang Schwarz

Same content, different truth value

Kaplan, "Demonstratives", p.500:

[I]f I say, today,

I was insulted yesterday

and you utter the same words tomorrow, what is said is different. If what we say differs in truth-value, that is enough to show that we say different things.

This criterion is frequently echoed. Here, for instance, is Lycan, Philosophy of Language, p.93:

...words on Twin Earth and the rest diverge in meaning from their counterparts on Earth. Of an Earth utterance and its Twin, one may be true and the other false; what more could be required for difference of meaning?

But the criterion strikes me as very implausible. Consider a possible world that differs from ours only by containing an extra isolated electron in some remote part of the universe, far outside our galaxy. When I say "the number of electrons is even", my utterance differs in truth value from the corresponding utterance of my twin at this world. Does it follow that we mean different things by "number" or "electron" or "even" (or "is")? No. The obvious explanation is rather that what both of us mean happens to be true in one world and false in the other.

Contexts of utterance without utterance tokens

I think one should not define "context of utterance" so that a context of utterance for an expression must always contain an utterance of the expression (or "truth in a context of utterance" so that a sentence can only be true in a context where it is uttered).

This obviously depends on how or where the term is meant to be used. The use I have mostly in mind is in the semantics/pragmatics of context-dependence, or indexicality.

Competent speakers of English know how to determine the semantic value(s) of a sentence uttered in a given context. Take truth value: we know that

(Unary) Numerical and Proportional Quantifiers

A quick Google search didn't come up with anything, so here are a couple of questions about the definability of certain unary quantifiers.

Just as all truth-functional operators are definable in terms of the Sheffer stroke, all numerical quantifiers are definable in terms of together with truth-functional operators and identity. By a numerical quantifier I mean a quantifier like "at least one", "at least two", "exactly 17", etc.: a quantifier Q such that the truth value of QxA(x) is determined by the finite cardinality of the objects satisfying A(x).

Trento

I'll be in Trento, Italy, next weekend. If anyone know a cheap place there to sleep and shower, please let me know.

Update 2006-05-02: I'm back. I've lived at Youth Hostel Giovane Europa, which is close to the station, 13,50 Euros per night and quite ok (as long as you don't mind an old man who only speaks Italian sleeping in your bed when arriving at night.)

What is my telephone number?

I just realized that I don't know what my telephone number is. I used to think it is 44717384. But 44717384 is a number, and the same as 252452510 in octal, or 2aa5548 in hexadecimal. Yet it sounds wrong to say that my telephone number is 252452510 in octal, or that my telephone number begins with 4 only in decimal notation. What's more, telephone numbers are never pronounced "forty-four million, seven hundred and seventeen thousand three hundred eighty-four". (I know an old woman in a rural part of Germany whose number used to be 543; she, too, always said "five four three".)

Humean Supervenience and Quantum Physics

When sometime between 1986 and 2001, Lewis accepted (a certain version of) standard quantum physics, did he thereby accept that Humean Supervenience is false? I'm not sure. My knowledge of quantum physics ("knowledge" in the sense of "probably false, unjustified guesses" rather than "true, justified beliefs") doesn't suffice to see through this with any confidence. Anyway, here's some thoughts.

Humean Supervenience is the hypothesis that in worlds like ours, all truths supervene on the spatiotemporal distribution of fundamental properties at spacetime points. This appears to contradict what quantum physics says about entangled states: if two electrons are suitably entangled, their combined state is a superposition of X-spin(electron 1)=up & X-spin(electron 2)=down and X-spin(electron 1)=down & X-spin(electron 2)=up (, or so), which is not determined by any local qualities of the individual electrons: there are no spin states A and B such that whenever some electron is in A and another one in B, then their mereological fusion is in this entangled state. So Humean Supervenience is false.

Is "true" hyper-intensional?

While I'm on the topic of repeating well-known mistakes, here's another idea I'm certainly not the first to come up with. Consider the liar paradox:

	L := "L is not true"
1)	Suppose L is true.
2)	Then "L is not true" is true (by definition of L).
3)	Then L is not true (by the Tarski Schema).
	etc.

The inference from (1) to (2) is only valid if "... is true" is an extensional or intensional context. So couldn't one block the paradox by declaring "true" hyper-intensional?

Slingshooting against the necessity of identity

The set is the empty set if p is false, otherwise it is the set of all numbers. Hence iff either p and q are both false or p and q are both true. So

Quantification in A-intensional semantics

Once upon a time, two quite different roles were assigned to truth-conditions: 1) they are what you know when you understand a sentence and what people communicate with utterances of the sentence; 2) they determine the truth value of the sentence when prefixed with modal operators. Unfortunately, there are sentences where these two roles come apart, namely context-dependent sentences, like "it's raining" and "I am late", and sentences containing rigid designators, like "London is overcrowded" and "Hesperus = Phosphorus". Since virtually all sentences ever uttered belong to one of these two classes (or both), the idea that we can assign to sentences truth-conditions that serve both (1) and (2) must be given up. The common strategy to deal with this at least among philosophers is to regard truth-conditions in the sense of (2) as the proper topic of compositional semantics and to assume that some other ("pragmatic") story will deliver truth-conditions in the sense of (1) out of the truth-conditions in the sense of (2) and various contextual features. I find that cumbersome and unmotivated. In my view, truth-conditions in the sense of (1) should be the primary topic of semantics, and I don't see any reason for the roundabout two-step procedure via truth-conditions in the sense of (2). I wouldn't complain if that procedure turned out to work sufficiently well, but for all I can tell, it doesn't work well at all. So I think it would be better to do compositional semantics directly for truth-conditions in the sense of (1). Since Frank Jackson calls such truth conditions "A-propositions" or "A-intensions", I use "A-intensional semantics" for that project.

Recursive Values

If I'd make a list of how people should behave, it would include things like

• avoid killing other animals, in particular humans
• help your friends when they are in need

etc. The list should be weighted and pruned of redundancy, so that it can be used to assign to every possible life a goodness value. Suppose that is done. I wonder if the list should contain (or entail) a rule that says that good people see to it that other people are also good: