1. Analytic ontology
Lezioni 26-27

2. Lezione 26
27 Novembre
(Lezione 25 del 26 Novembre ore 8,30: VITTORIO MORATO, "Contingent necessity-makers")

3. Identity through time

4. Useful references André Gallois, The Metaphysics of identity

5. Data and problems Persistence with qualitative change
Lewis' problem of temporary intrinsics
Tibbles and Tib
The ship of Theseus
Fission
symmetric: amoeba
asymmetric: ship of Theseus with Hobbes' reconstructed ship
Fusion
The lizard's tail fell off but then it grew back

6. Approaches (in grassetto quello che tratteremo in dettaglio)
3-dimensionalism
cum endurantism (cum genuine identity) (Strawson, Wiggins, Lowe)
cum sequentialism (conventionalism) (Chisholm in "identity through time")
4-dimensionalism
cum perdurantism (cum "genidentity") (objects as mereological sums of stages) (Quine, Lewis)
cum sequentialism (conventionalism) (Chisholm in "Problems of identity"; Sider's stage view; Katherine Hawley (sep entry on temporal parts)
I am using "sequentialism" as in Varzi, Parole, Oggetti, Eventi (2001, pp )
(Quasi-)Nihilism: there are no composite objects (except persons and pehaps other living beings (Van Inwagen, Material beings; Merricks Objects and persons)
Lewis in On the plurality of words
Quine in From a logical point of view, "id., ost, hyp" (Varzi anthology) and W&O?
for the origin of "genidentity" see Orilia 2002, p. 202, n. 4
Lewis in On the plurality of worlds

7. Program
3-dimensionalism (presentism) cum endurantism and thus genuine, real identity across time is seemingly the view of common sense, but it must face puzzles such as Tibbles the cat, and Theseus. I shall discuss Wiggins' and Lowe's attempts today and tomorrow (NB: Wiggins does not explicitly deals with presentism/eternalism and Lowe's position is not completely transparent to me)
With 4-dimensionalism and/or sequentialism we seem to go away from common sense. Positions of this sort will be discussed in lesson 30:
Alessandro Pianese: Chisholm
Francesca De Simone: Sider
It should be noted that, according to Sider, the satisfactory four-dim treatment of the puzzles about identity turns out to be an asset for (B-) eternalism

8. Tibbles, the cat
Discussed by Wiggins (PR 1968, Varzi anth. §2.2), who attributes it to Geach, who in turn takes it from William of Sherwood (but it can be traced back to the Stoics; see Varzi anth., p. 93; Attribution to Crisippus in Varzi Il mondo messo a fuoco, 2010, p. 86)
Also discussed by Lowe (Kinds of beings, Varzi anth. § 2.3). Same solutions but further details
Similar problem (with Descartes' losing his left hand) in Loux p. 222
There is a certain cat, Tibbles, at time t1. At time t2, Tibbles loses its tail.
two questions ...

9. The 2 questions
There is a certain cat, Tibbles, at time t1. At time t2, Tibbles loses its tail. Is the new, mutilated, Tibbles identical to the old Tibbles? Or is the new Tibbles identical to Tib, i.e., the old Tibbles minus the tail, an object which, we may say, existed at t1 as proper part of Tibbles?
(1) New Tibbles = Old Tibbles ?
(2) New Tibbles = Tib (i.e., Old Tibbles  Tail) ?

10. Dualism (pluralism) about objects
Two supporters: Wiggins, Lowe
Distinguish between an object and the aggregate of matter that constituite it
Classical example: the statue and the clay
Typical motivation: different identity conditions across time. The statue keeps existing even if losing a little piece. Without that little piece, we have a different clay aggregate.
These prima facie compelling principles are rejected:
PC. Co-localization principle: x and y are in the same place at the same time  x = y (accepted by Locke, ESSAY CONCERNING HUMAN UNDERSTANDING, II, 27, §1)
PM. mereological principle: x and y have the same parts  x = y

11. 1st reply by Wiggins and Lowe
(1) New Tibbles = Old Tibbles ?
Following common sense we should answer yes: we typically admit that an object can lose a little part and yet continue to exist; it persists.
This can be supported by endorsing dualism: we must distinguish between the object and the material parts, or the aggregate of matter, out of which it is constituted at a given time.
dualism leads a denial of PC, the thesis that two distinct entities cannot occupy the same portion of space at the same time.
For we must say that both the object and the aggregate of matter that constitutes the object occupy the same region of space.
But we can still say that no objects of the same type can occupy the same portion of space at the same time: the object and the aggregate are of different type (Wiggins in Varzi anth. p. 20).

12. Since the ordinary object and the aggregate of matter that constitutes the object have the same parts, we must also deny
PM. mereological principle: x and y have the same parts  x = y
We are also led to a denial of mereological essentialism, according to which all the parts of an object are essential to the identity of an object. Thus, an ordinary object does not essentially depend on its parts for its existence.

13. 2nd reply by Lowe and Wiggins
(1) New Tibbles = Old Tibbles ?
(2) New Tibbles = Tib (i.e., Old Tibbles  Tail) ?
Suppose one is tempted to say that the new Tibbles is identical to Tib, because
(a) New Tibbles and Tib are made up of the same physical parts and have the same shape.
However, having replied yes to (1), the answer to (2) must be no.
Let us see why and how this answer can be made palatable ...

14. The problem with the yes answer to (2)
If we accept both identities, i.e., we accept both
(1) old Tibbles = new Tibbles
(2) new Tibbles = Tib
by the transitivity of identity we should also accept
(3) old Tibbles = Tib
In other words, we should say that Tibbles was identical to a proper part of it, but this cannot be the case. They have different properties, for example they occupy different portions of space. We must reject either (1) or (2)
We saw Wiggins and Lowe save (1). Let us further clarify why ...

15. The rejected hypothesis
Suppose we accept
(1) old Tibbles  new Tibbles
(2) new Tibbles = Tib
Not so good:
it means that we are in fact accepting that the new Tibbles was not a cat (as it is not identical to the cat old Tibbles), it rather was a part of cat (who has now become a cat).
Moreover, we must admit that by simply losing its tail Tibbles ceases to exist

16. The accepted hypothesis
This seems the best solution:
(1) old Tibbles = new Tibbles
(2) new Tibbles  Tib
Which justification?

17. Lezione 27
28/11/18

18. READINGS SUGGESTED FOR NEXT WEEK:
I will send them

19. Wiggins’ justification
The solution:
(1) old Tibbles = new Tibbles
(2) new Tibbles  Tib
Wiggins motivation is that Tib and the new Tibbles are really not of the same type: the new Tibbles is a cat, whereas Tib is only a part of a cat.
NB: this saves the principle that no two objects of the same type can occupy the same place at the same time: at time t2 we DO NOT have two cats: Tib, to whom nothing happened, and Tibbles, a cat who lost a tail. WHY? Tib is only a part of a cat
But there is a leftover problem …

20. (a) New Tibbles and Tib are made up of the same physical parts and have the same shape.
doesn’t Tibbles coincide at t2 with Tib? Given that Tibbles lost its tail, how can Tib be at t2 only a part of Tibbles rather than being identical with Tibbles?
Enter Lowe …

21. Lowe
What is at issue really is the distinction between the object and the aggregate of matter that constitutes it: Tib is the aggregate and Tibbles the object.
At t2 Tib can still be seen as a part of a cat, but it is not a proper part, i.e., it wholly constitutes Tibbles. Call Tail the tail of Tibbles
At t1: Tibbles  Tib+Tail.
Why? Tib+Tail is a mere aggregate, which does not survive the annihilation of its part Tail, whereas Tibbles is a cat, who can survive the loss of a part.
In sum, a cat is a sort of whole that is distinguished from any sum of its parts. Such wholes are called by Lowe organic (in his SEP entry on ontological dependence).
2 kinds of collective (summative) objects: aggregates, whose parts are connected as in a cat) and heaps, whose parts are NOT connected, as in a heap of sand.

22. the ship of Theseus
at t1 the planks and all pieces of the original ship in the harbour start being replaced until at tn all pieces are new and the renovated ship is left in the harbour (Plutarch)
The old pieces are collected and a reconstructed ship is left in a warehouse at tn (Hobbes)
Various hypotheses at tn
(1) original ship = renovated ship
(2) original ship = reconstructed ship
(3) original ship no longer exists

23. the options (1)-(3) are incompatible
(1) original ship = renovated ship
(2) original ship = reconstructed ship
These cannot be jointly accepted otherwise, by transitivity, we get this absurd result:
(A) renovated ship = reconstructed ship
Yet, there are good reasons for both (1) and (2). What shall we do?
Choose (3)?
(3) original ship no longer exists

24. Lowe's solution
Cfr. Lowe, A Survey of metaphysics p. 27 ss. (anche in ‘On the identity of artifacts’, JP 1983)
A position analogous to Lowe's in: Brian Smart, ‘How to reidentify the ship of Theseus’ (Analysis 34 (1): (1973); also in ch. 20 of Rea, ARGUING ABOUT METAPHYSICS (MC: FILOS XI 575)
(1) original ship = renovated ship
(1b) original ship  reconstructed ship
(1c) reconstructed ship is a new object that starts existing at tn.
Why?

25. On the identity of artifacts
An artifact is an object that can be "gruadually disassembled and later reassembled", which can undergo the substitution of parts, even all parts, and which can also lose some parts. Hence: original ship = renovated ship
We must distinguish between:
(A) an ordinary disassembling/reassembling case (e.g. for maintenance), wherein all parts remain available for reassembling.
(B) a Theseus case wherein all the disassembled parts (or "sufficiently many"; p. 33) are "appropriated" by another NEW object. Hence: original ship  reconstructed ship

26. a distinction I would make this distinction not made by Lowe
(1) Preserving disassembling wherein (almost) all parts are saved and remain ready to be reassembled
(2) Dispersing disassembling wherein (almost) all parts are (deliberately) dispersed and scattered and thus no longer available for reassembly
Does the ship continue to exist only in case (1)? I tend to say yes. But then there seems to be a sort of mind-dependence of the object. Perhaps it's OK for artifacts

27. A problem for Lowe
(Q) Should we say that the original ship would have been identical to the reconstructed ship, if the parts had been removed without being replaced, so that the renovated ship had not existed?
If we say YES, we end up admitting (Implausibly!) that an identity, the original ship = the reconstructed ship, depends on whether or not a tertium, the renovated ship, exists (Lowe is not explicit, but he seemingly wants to avid this)

28. Lowe's answer
(Q) Should we say that the original ship would have been identical to the reconstructed ship, if the parts had been removed without being replaced, so that the renovated ship had not existed?
Lowe avoids the yes answer to Q in this semantic way: "the reconstructed ship" has different referents in the two cases: a ship that starts existing at tn, and a ship that already existed before tn
This is because in the counterfactual case of (Q) we would have an ordinary disassembling/reassembling case [Lowe imagines the parts are stored in a warehouse; p. 26]
However, ...

29. Can semantics really help here?
Lowe says there are two referents for " the reconstructed ship ", because he takes for granted that:
(a) in a world w with the the renovated ship existing at tn, the reconstructed ship is a new object, which starts existing at tn
(b) in a world w' in which the renovated ship does not exist at tn, the reconstructed ship already existed, since it is identical to the original ship existing at t1.
But it is what is taken for granted that is problematic, as it makes the identity of an object dependent on something else. It may be a price that this approach has to accept

30. Blue World W vs. Red World W'
W: t1: ship(p1, p2, p3, ..., pn) [assembled ship]
t2: p1, p2, p3, ..., pn [scattered parts of ship]
t3: ship(p1, p2, p3, ..., pn) [assembled ship again]
W' t1: ship(p1, p2, p3, ..., pn) [reassembled ship]
t2: p1, p2, p3, ..., pn & ship(p*1, p*2, p*3, ..., p*n) [scattered parts of ship & ship with new parts]
t3: ship(p*1, p*2, p*3, ..., p*n) & ship(p1, p2, p3, ..., pn) [ship with new parts & assembled ship again]