Motivations for Counterpart theory Counterpart theory

1 motivations counterpart theory

1.1 in possible worlds

1.1.1 overlapping individuals
1.1.2 trans-world individuals
1.1.3 haecceity


1.2 temporal parts

motivations counterpart theory

ct can applied relationship between identical objects in different worlds or @ different times. depending on subject, there different reasons accepting ct description of relation between different entities.

in possible worlds

david lewis defended modal realism. view possible world concrete, maximal connected spatio-temporal region. actual world 1 of possible worlds; concrete. because single concrete object demands spatio-temporal connectedness, possible concrete object can exist in 1 possible world. still, true things like: possible hubert humphrey won 1968 presidential election. how true? humphrey has counterpart in possible world wins 1968 election in world.

lewis argues against 3 other alternatives might compatible possibilism: overlapping individuals, trans-world individuals, , haecceity.

some philosophers, such peter van inwagen (1985), see no problem identity within world . lewis seems share attitude. says:

… holy roman empire, badly named. […] in first place should bear in mind trans-world airlines intercontinental, not yet interplanetary carrier. more important, should not suppose have here problem identity.


we never have. identity utterly simple , unproblematic. identical itself; nothing ever identical else except itself. there never problem makes identical itself; nothing can ever fail be. , there never problem makes 2 things identical; 2 things never can identical.


there might problem how define identity sufficiently lacking in conceptual resources — note won t suffice teach him rules of inference — since such unfortunates rare, among philosophers, needn t worry if condition incurable.


we state plenty of genuine problems in terms of identity. needn t state them so.” (lewis 1986:192-193)

overlapping individuals

an overlapping individual has part in actual world , part in world. because identity not problematic, overlapping individuals having overlapping worlds. 2 worlds overlap if share common part. properties of overlapping objects are, lewis, troublesome (lewis 1986:199-210).

the problem object’s accidental intrinsic properties, such shape , weight, supervene on parts. humphrey have property of having 6 fingers on left hand. how that? can’t true humphrey has both property of having 6 fingers , 5 fingers on left hand. might has 5 fingers @ world , 6 fingers @ world. how should these modifiers understood?

according mcdaniel (2004), if lewis right, defender of overlapping individuals has accept genuine contradictions or defend view every object has properties essentially.

how can 1 year older are? 1 way there possible world exist. way have counterpart in possible world, has property of being 1 year older you.

trans-world individuals

take humphrey: if trans-world individual mereological sum of of possible humphreys in different worlds. road goes through different regions. there parts overlap, can there northern part connected southern part , road mereological sum of these parts. same thing humphrey. 1 part of him in 1 world, part in world.

possible exist iff possible whole exist. is, iff there world @ whole of exists. is, iff there world such quantifying on parts of world, whole of exists. is, iff whole of among parts of world. is, iff part of world – , hence not trans-world individual. parts of worlds possible individuals; trans-world individuals therefore impossible individuals.

haecceity

a haecceity or individual essence property single object instantiates. ordinary properties, if 1 accepts existence of universals, can exemplified more 1 object @ time. way explain haecceity distinguish between suchness , thisness, thisness has more demonstrative character.

david lewis gives following definition of haecceitistic difference: “two worlds differ in represent de re concerning individual, not differ qualitatively in way.” (lewis 1986:221.)

ct not require distinct worlds distinct possibilities – “a single world may provide many possibilities, since many possible individuals inhabit it” (lewis 1986:230). ct can satisfy multiple counterparts in 1 possible world.

temporal parts

perdurantism view material objects not wholly present @ single instant of time; instead, temporal parts said present. sometimes, in theory of relativity expressed minkowski, path traced object through spacetime. according ted sider, “temporal parts theory claim time space in 1 particular respect, namely, respect parts.” sider associates endurantism c-relation between temporal parts. (see also: argument temporary intrinsics).

sider defends revised way of counting. instead of counting individual objects, timeline slices or temporal parts of object used. sider discusses example of counting road segments instead of roads simpliciter. (sider 2001:188-192). (compare lewis 1993.) sider argues that, if knew material object go through fission , split two, not there 2 objects located @ same spacetime region. (sider 2001:189)

how can 1 predicate temporal properties of these momentary temporal parts? here c-relation comes in play. sider proposed sentence: ted once boy. truth condition of sentence there exists person stage x prior time of utterance, such x boy, , x bears temporal counterpart relation ted. (sider 2001:193)