PHIL 2000 Philosophical Tools 1st Term 2016 Naming and Necessity PHIL 2000 Philosophical Tools 1st Term 2016

Possible Worlds

Necessary vs. Contingent Necessary = “could not have been false” Note on modal auxiliary ‘could have’: personal, physical, metaphsycial Contingent = “could have been false” Metaphysical distinction, not epistemological Cf. “Can believe it’s false” vs. “Can’t believe it’s false”

A Posteriori Necessities Things that must be true, but need to be investigated to be known. Informative identity statements “Whales are mammals.” “Lightning is an electrical discharge.” Necessity of origin: Michael’s parents must have been Lowell and Wendy Johnson.

Moore’s Open Question Argument What is it for an act to be morally good? Can there be a natural property that is identical to the property of being morally good? Suppose there can, call it X. Then things that are X should obviously (a priori) be morally good, because X = moral goodness. But it’s always an open question: “Are the things that are X morally good?” So there is no such natural property.

An Argument for Dualism What is a conscious experience? Can conscious experiences be identified with physical states of the brain? Suppose seeing red = being in brain state B. Then it should be a priori that beings that see red are in brain state B. But I can imagine beings that are in B, but don’t see red (philosophical zombies, inverted spectrum cases…) Therefore, seeing red is not the same thing as being in any brain state.

A Priori Contingencies Things that could have been false, but can still be known without investigation. Cartesian truths? “I think”, “I exist”, “I have the idea of God”– are these the result of experience with the relevant facts? A posteriori certainties?? “Jack the Ripper was a murderer.” “Homer wrote the Iliad.” (Cf. “Shakespeare wrote Hamlet.”) “Dark energy is responsible for the universe’s expansion.”

Possibility A statement is possible if it can be true. Contingently true OR contingently false OR necessarily true Not necessarily false. P is possible = not necessarily not-P P is necessary = not possibly not-P

Possible Worlds Some things are not true, but they could have been true. It could have been true that there were talking donkeys, even though there aren’t actually any talking donkeys.

Possible Worlds Some philosophers have tried to analyze possibility in terms of possible worlds: It is possible that P. = In some possible world, it is true that P.

The Multiverse Important: some physicists believe our universe is part of a multiverse of universes. This is different from the philosophers notion of possible world. In particular, physicists are not committed to the claim that in some other universe, donkeys talk.

Possible Worlds Philosophers who believe in possible worlds disagree about what they are. According to Lewis: Possible worlds are just as real, and made out of the same sorts of things as the world we live in. They are universes that are not spatially connected to ours, so we cannot go there or change what happens there.

Possible Worlds Robert Stalnaker, however, thinks that possible worlds are not concrete universes. They are instead a type of uninstantiated property: Possible worlds are maximally specific ways that our world could have been.

Possible Worlds Possible worlds are maximally specific ways that our world could have been. This doesn’t particularly help with analyzing modality.

Classical Descriptivism

Representation Words/ thoughts have meanings. They are about things. Why do words, for example, represent the things that they do, instead of other things or nothing at all?

Classical Descriptivism For every name N, there is a description D that we associate with N such that: If x satisfies D, then N refers to x. If N refers to x, then x satisfies the description.

Classical Descriptivism We may say, following Russell: the name “Moses” can be defined by means of various descriptions. For example, as “the man who led the Israelites through the wilderness”, “the man who lived at that time and place and was then called ‘Moses’”, “the man who as a child was taken out of the Nile by Pharaoh's daughter” and so on. Investigations Section 79

Classical Descriptivism Moses: Lead the Israelites out of Egypt Parted Red Sea Given 10 commandments by God

Classical Descriptivism This guy Lead the Israelites out of Egypt Parted Red Sea Given 10 commandments by God

Classical Descriptivism Moses refers

Classical Descriptivism This guy Lead the Israelites out of Egypt Parted Red Sea Given 10 commandments by God

Classical Descriptivism Moses refers

Kripke against Descriptivism

Saul Kripke, 1940- Published first completeness proof for modal logic at 18. Highly influential in philosophy of language and mind. Developed the causal-historical theory of meaning

Saul Kripke, 1940- Kripke’s account is developed in his Naming and Necessity. The background is that he’s arguing against views on which the meanings of names are descriptions or definitions.

Against Descriptivism Kripke argues that for any name N, there is no description D that we associate with N such that: If x satisfies the description, N refers to x. If N refers to x, then x must satisfy the description.

Ignorance & Error He argues against each claim as follows: Against #1: Arguments from ignorance. Sometimes lots of things satisfy the descriptions we associate with N, but only one is N. Against #2: Arguments from Error. Sometimes nothing satisfies the descriptions we associate with N (or some non-x does), but N still = x.

Ignorance: Feynman What people know: He’s a physicist He’s famous He’s dead He worked on quantum mechanics

Ignorance: Feynman But Bohr: He’s a physicist He’s famous He’s dead He worked on quantum mechanics

Ignorance: Feynman it’s not true that ‘Feynman’ means Bohr and it’s not true that it means nothing. How is that possible for the descriptivist?

Error: Einstein Who is Albert Einstein? What people believe: Einstein is the inventor of the atomic bomb.

Error: Einstein But “the inventor of the nuclear bomb” can’t be the meaning of ‘Einstein’ because then ‘Einstein’ would refer to Leo Szilard (or whoever).

Causation & Representation

The Mirror Universe

Secondary Qualities

Possibility of Massive Error

Coordination across Theories A related upshot is that two people with radically different theories can nevertheless be talking about the same thing, and hence be meaningfully disagreeing with one another.

The Causal-Historical Account

Kripke’s Picture “Someone, let’s say, a baby, is born; his parents call him by a certain name. They talk about him to their friends, other people meet him. Through various sorts of talk the name is spread from link to link as if by a chain…”

Kripke’s Picture “A speaker who is on the far end of this chain, who has heard about, say Richard Feynman, in the market place or elsewhere, may be referring to Richard Feynman even though he can’t remember from whom he first heard of Feynman or from whom he ever heard of Feynman.”

Kripke’s Picture “A rough statement of a theory might be the following: An initial ‘baptism’ takes place. Here the object may be named by ostension, or the reference of the name may be fixed by a description…”

Kripke’s Picture “When the name is ‘passed from link to link’, the receiver of the name must, I think, intend when he learns it to use it with the same reference as the man from whom he heard it.”

The Causal-Historical Theory Let’s call that baby ‘Feynman’ Feynman Feynman Feynman Feynman

The Causal-Historical Theory Let’s call that baby ‘Feynman’ Feynman Feynman Feynman Feynman Historical Chain of Transmission

The Causal-Historical Theory Feynman Feynman Feynman Feynman Denotation

No Connotations The causal-historical theory, unlike the other theories, does not use mental facts (idea, experience, definition) to determine a referent. Denotations are determined by non-mental facts.* *Plus one intention for each link in the chain.

Natural Kinds Kripke and another philosopher Hilary Putnam wanted to generalize what was true of names to “natural kind terms” (a phrase introduced by Quine).

The Causal-Historical Theory Let’s call that thing a “tiger.” TIGER TIGER TIGER TIGER

Ignorance: Water In Hilary Putnam’s classic “The Meaning of ‘Meaning’” he argues that “meaning just ain’t in the head.” In particular, he presents his famous Twin Earth thought experiment, which is intended to show that what the word ‘water’ is true of is not determined by what we know or believe about water.

Twin Earth Twin Earth is a planet on the other side of the galaxy. In most ways, it is just like Earth, down to the smallest detail. You have a twin on Twin Earth who’s just like you, I have a twin who’s just like me, they’re sitting in a twin classroom, and my twin is giving a lecture just like this one to your twin. And so on and so forth.

Earth Twin Earth

Twin Earth There is however one difference between Earth and Twin Earth. On Earth, all the watery stuff is H2O. On Twin Earth, the watery stuff is composed of a complicated chemical compound we can abbreviate XYZ. H2O and XYZ look and behave exactly the same. They taste the same, they boil at the same temperatures at the same distance above sea level, their conductance is the same, etc.

Twin Earth Consider two twins, Arnold on Earth and Twin Arnold on Twin Earth. Neither knows any chemistry. What they know/ believe about the stuff they call ‘water’ is the same. Q: Would it be true for Arnold to call the stuff on Twin Earth ‘water’?

Twin Earth The intuition is supposed to be that, no, Arnold’s word ‘water’ is true of all an only H2O, whereas Twin Arnold’s word ‘water’ is true of all and only XYZ

The Moral The conclusion Kripke and Putnam draw from such cases is that we fix the referent of ‘water’ by a description like “the stuff around here in lakes and rivers and streams that falls from the sky and quenches thirst.” But this description only fixes the referent. If you replaced all the H2O on Earth with XYZ, there wouldn’t be any more water here.