Gibbard, “Contingent Identity” Against Kripke, for whom identity statements involving names (rigid designators) are necessary. Gibbard wants to argue that there are contingent identities involving proper names and that names are only rigid designators relative to a sortal. I.e. Gibbard’s piece concerns both contingent identity and relative identity.

Gibbard’s story: The statue and the clay “I make a clay statue of the infant Goliath in two pieces, one the part above the waist and the other the part below the waist. Once I finish the two halves, I stick them together, thereby bringing into existence simultaneously a new piece of clay and a new statue. A day later I smash the statue, thereby bringing to an end both statue and piece of clay. The statue and the piece of clay persisted during exactly the same period of time.” (102a) So, it seems that the statue and the piece of clay are identical.

If we name the statue and the piece of clay, we can get the following, which is supposed to be a statement of their contingent identity: Goliath = Lumpl & à (Goliath exists & Lumpl exists & Goliath ≠ Lumpl). Now, suppose that Gibbard squeezes his statue and clay together while the clay is still soft. In this case, the piece of clay continues to exist but the statue stops existing. So, Lumpl exists & Goliath exists & Goliath ≠ Lumpl. That is, they are at one time identical, at another time not; that is, they are contingently identical. (102b)

If all names are rigid designators, then Goliath can’t be identical with Lumpl. (103b) “A rough theory begins to emerge from all this. If Goliath and Lumpl are the same thing, asking what that thing would be in W´ apart from the way the thing is designated, makes no sense. Meaningful cross-world identities of such things as statues, it begins to seem, must be identities qua something: qua statue or qua lump, qua Goliath or qua Lumpl. It makes no sense to talk of the ‘same statue’ in different possible worlds, but no sense to talk of the ‘same thing’.” (104a) “Goliath” refers to something as a statue; “Lumpl,” as a lump.

Two problems: First, how do names get their references in the actual world? Second, what makes a thing in another possible world “the same statue” as the one in the actual world? (104b) The reference of a proper name in a branching world depends upon two things: its reference in the actual world, and the persistence criteria it invokes. (105a) The reference of a proper name in the actual world is fixed partly by invoking a set of persistence criteria which determine what thing it names…. The name can be used to refer to a thing in a possible world which branches from the actual world after the thing named in the actual world begins to exist. (106a) Identity across possible worlds only makes sense with respect to a sortal.

What’s a ‘branching world’? One possible world branches off from another iff they are identical up to time t and different thereafter. “The Garden of Forking Paths” So, two things in different possible worlds could be designated with the same names if there worlds were identical up to their dubbing and they had the same origin.

Leibniz’s Law and the de re/de dicto distinction The most prominent objection to contingent identity is that it violates Leibniz’s Law. But no problem. Leibniz’s Law ought only concern properties and relations. In Gibbard’s system, concrete objects have no modal properties. I.e. no de re modality for concrete objects. De re vs. de dicto modality: De dicto: Necessarily, the number of planets is odd. (I’ll include Pluto!) De re: The number of planets is necessarily odd. (Generally speaking, when people talk of de re modality, they mean that objects have essential properties.)

Essentialism for a class of entities U: for any entity e in U and any condition φ which e fulfills, the question of whether e necessarily fulfills φ has a definite answer apart from the way e is specified. Essentialism holds for concepts but not for objects. Why not for objects? “Essentialism … is false for concrete things because apart from a special designation, it is meaningless to talk of the same concrete thing in different possible worlds.” (111a) Why? Because things are only the same relative to a sortal.

Yablo, “Identity, Essence, and Indiscernibility” Guiding question: “Can things be identical as a matter of fact without being necessarily identical?” “[E]ssentialism without some form of contingent identity is an untenable doctrine, because essentialism has a shortcoming that only some form of contingent identity can rectify” (116b) Purpose of the paper: (1) explain why contingent identity is required by essentialism, and (2) explain how contingent identity is permitted by essentialism.

Paradox of Essentialism If α has P necessarily and β has P accidentally, then α and β must be distinct. (following PII) (116b) Consider the hunk of wax and the bust of Aristotle (essentially the same issue as Gibbard’s Goliath and Lumpl). If essentialism is to be at all plausible, non-identity had better be compatible with intimate identity-like connections. (117a)

What is a thing? Begin with a particular thing α. What is α? How should α be characterized? Complete profile of α: set of all properties of α. The properties of α will generally be of two kinds: those which α had to have and those which it merely happens to have. Complete essence of α: the set of properties that α possesses essentially, after dropping α’s non-necessary properties from its complete profile.

Contingent Identity (1) The Shroud of Turin had to enshroud Jesus. (2) The Cloth of Turin did not.  (3) It would seem that they must be different. But the Shroud of Turin is also distinct from the Treaty of Versailles. And it seems wrong to say that the differences are for the same reasons. Maybe it is really the contingent identity or coincidence of the Shroud and the Cloth.