XVII. Absolute versus relative identity
XVII. a. Identity & persistence conditions
- Entities having different identity & persistence conditions
o Example: pile of stone ≠ persisting through mereological change all
sums ≠ mereologically variable ( application to ship of Theseus?)
o Example: lump of matter persisting through rearrangement with ≠
deduction/addition of matter all sums persisting through changes in form
o Example: wall ≠ persisting through changes in form
- Differences in types of changes possible for entities without changing identity
o Example: caterpillar transforming into butterfly persisting through total
reorganisation of parts (= metamorphosis) while remaining same creature
Features of butterfly prefigured in caterpillar
- Different kinds of things having different persistence conditions
XVII. b. Dilemma
- Incompatible claims
1) two different physical objects ≠ occupying same physical space at same time
2) relationship between entity & composite (i.e., vase & lump of bronze) – entity
& composite having different persistence conditions
3) two entities having different persistence conditions different distinct entities
XVII. c. Possible responses
1) XXXX
- Thesis: two entities able existing in same space at same time
- Problem: two entities sharing exact same empirical properties in time of
occupying same space = intuitively identical
o Futility of distinguishing two identities sharing exact same empirical
properties & same exact physical space
o Violation of identity of indiscernibles
- Response: two entities sharing only some empirical properties having
different historical & modal properties
- Counter-response: (see lecture 17 recording)
2) Lewis’s theory of temporal parts
- Two entities (i.e., lump of bronze & statue) = same entity due to theory of
temporal parts (= objects composed of temporal parts)
- Two entities sharing exact same temporal parts when occupying same space
identity of entities even when previously having different historical
properties & persistence conditions
XVII. a. Identity & persistence conditions
- Entities having different identity & persistence conditions
o Example: pile of stone ≠ persisting through mereological change all
sums ≠ mereologically variable ( application to ship of Theseus?)
o Example: lump of matter persisting through rearrangement with ≠
deduction/addition of matter all sums persisting through changes in form
o Example: wall ≠ persisting through changes in form
- Differences in types of changes possible for entities without changing identity
o Example: caterpillar transforming into butterfly persisting through total
reorganisation of parts (= metamorphosis) while remaining same creature
Features of butterfly prefigured in caterpillar
- Different kinds of things having different persistence conditions
XVII. b. Dilemma
- Incompatible claims
1) two different physical objects ≠ occupying same physical space at same time
2) relationship between entity & composite (i.e., vase & lump of bronze) – entity
& composite having different persistence conditions
3) two entities having different persistence conditions different distinct entities
XVII. c. Possible responses
1) XXXX
- Thesis: two entities able existing in same space at same time
- Problem: two entities sharing exact same empirical properties in time of
occupying same space = intuitively identical
o Futility of distinguishing two identities sharing exact same empirical
properties & same exact physical space
o Violation of identity of indiscernibles
- Response: two entities sharing only some empirical properties having
different historical & modal properties
- Counter-response: (see lecture 17 recording)
2) Lewis’s theory of temporal parts
- Two entities (i.e., lump of bronze & statue) = same entity due to theory of
temporal parts (= objects composed of temporal parts)
- Two entities sharing exact same temporal parts when occupying same space
identity of entities even when previously having different historical
properties & persistence conditions
