# Philosophy Lexicon of Arguments

Author Item Excerpt Meta data
Lewis, David

Books on Amazon
Counterpart Theory IV 26f
Counterpart theory/Lewis: alternative to modal logic with modal operators - then we have no non-eliminable singular term.
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IV 27
Four basic predicates: Wx (x is a possible world) - ((s)> Quantity) - Ixy (x is inside the poossible world y) - ((s)> containment, element relation) - Ax (x is actual) - ((s)> existence) - Cxy (x is a counterpart of y) - ((s)> correspondence, bearer of possibl.>cross world identity)- Eight postulates/logical form: P1: (x)(y)(Ixy>Wy) - everyday language translation: (Nothing is in something other than a world) - P2: (x)(y)(z)(Ixy & Ixz. > y = z) - (Nothing is in two worlds) - P3: (x)(y)(Cxy > E zIxz) - (whatever is a counterpart, is always in a world) - P4: (x)(y)(Cxy> E zlyz)- (Whatever has a counterpart, is in a world) P5: (x)(y)(z)(Ixy&Izy&Cxz. > x = z) - (Nothing is a counterpart of something in the same world) P6: (x)(y)(Ixy>Cxx) - (Every thing in a world is a counterpart of itself) - P7: (Ex)(Wx&(y)(Iyx ↔ (Ay)) - (A World contains all and only actual things) - P8: ExAx - (Something s actual) - The world mentioned in P7 is unique because of P2 and P8 - World/logical form/Actual world/Lewis: - @ = def ix(y)(Iyx ↔ Ay) (the actual world).
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IV 28
Counterpart relation: is generally not an equivalence relation - i.e. It does not apply between the pairs with the same first term (as Carnap would say. Lewis: no thing is in several worlds) - no matter how you tried to identify them - it is not transitive either, because similarity is not transitive - it is not symmetrical either: E.g. assuming x3 in w3 is a mixture of you and your brother and resembles you more than anything else in w3, so x3 is your counterpart.
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IV 29
But assuming the similarity of x3 with your brother is much greater, then you are not the counterpart of x3 - a thing does not need to have a CP in every world.
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IV 42
Counterpart theory/CPT/Lewis: we need counterpart relations in order to be able to determine the essence of something - Problem CPR are not very secured - problem:> similarity.
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IV 44f
Counterpart theory/Lewis: Problem: e.g. two pairs of twins in different possible worlds - they are more similar to the two than any other thing - Question: (double de-re) could the first twins not have lived on two different planets as relatives? - simply de re: Originally the two could simply not have be related (in the same world)? - If that is counterintuitive depends on how the question is asked - Lewis: Double de-re questions should be avoided - they result in duplicate counterpart relations - pairs of counterparts should not be construed as counterparts of pairs. ((s)> Bizet/Verdi).
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IV 54
Referentially transparent/De re/Modal/Normal CPT/Lewis: in my CPT all modal de re predications are referentially transparent - i.e. something has the same counterparts, no matter how we refer to them.
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V 20
Counterpart theory/Lewis: from it follows that the real imperator is not free to cross the Rubicon or not - only his counterpart could refrain - counterpart relations (CPR) and proximity to possible worlds are equally a matter of similarity, but they are independent of one another.

LW I
D. Lewis
Die Identität von Körper und Geist Frankfurt 1989

LW II
D. Lewis
Konventionen Berlin 1975

LW IV
D. Lewis
Philosophical Papers Bd I New York Oxford 1983

LW V
D. Lewis
Philosophical Papers Bd II New York Oxford 1986

LwCl I
Cl. I. Lewis
Mind and the World Order: Outline of a Theory of Knowledge (Dover Books on Western Philosophy) 1991

> Counter arguments against Lewis
> Counter arguments in relation to Counterpart Theory

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Ed. Martin Schulz, access date 2017-04-29