Gibbard, Contingent Identity

1
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. Gibbards piece concerns both contingent
  identity and relative identity.

2
Gibbards 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.

3

• 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)

4

• If all names are rigid designators, then Goliath
  cant 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.

5

• 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.

6
Whats 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.

7
Leibnizs Law and the de re/de dicto distinction

• The most prominent objection to contingent
  identity is that it violates Leibnizs Law. But
  no problem. Leibnizs Law ought only concern
  properties and relations.
• In Gibbards 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. (Ill 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.)

8

• Essentialism for a class of entities U for any
  entity e in U and any condition f which e
  fulfills, the question of whether e necessarily
  fulfills f 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.

9
Yablo, Identity, Essence, and Indiscernibility

• Guiding question Can things be identical as a
  matter of fact without being necessarily
  identical?
• Essentialism 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.

10
Paradox of Essentialism

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

11
What is a thing?

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

12
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.