|
|
Introduction to Philosophy |
An object retains its identity only insofar as the components that make it up retain their identity.
Objection: Heraclitus' river, as construed by Plato. It is absurd to think that 'you cannot step into the same river twice'.
But if identity can be retained even though components come and go, can a thing change all its components and still stay the same thing?
The story of the Ship of Theseus brings out the difficulty of thinking this. The story can be developed to hammer home difficulties with the mereological theory.
The Spatio-temporal continuity theory is of course not without difficulties of its own.
Difficulties for belief in
Multiple personalities
Reincarnation
If I can remember being here 15 weeks ago I am the same person who appeared before you on this challenging spot 15 weeks ago.
Personal identity consists in the continuation of an immaterial substance, a mind or soul.
Nice things about the non-physical entity theory
Difficulties
Mysterious relationship to the physical world
You can't tell the difference between one self and a succession of selves.
Hume's objection
Summary: Our ideas are not always copies of what is there in the external world.
The thesis that some aspects of a thing perceived are copied in the idea that you form of it, but some aren't.
The silent fall of an unheard tree
The thesis that in perception we are directly aware not of an object in the world but of representations in our minds
Arguments for
from the time-gap in all perception
from variations in perception
Significance of
The possibility of insanity
Dreaming
Geometry and arithmetic subject to doubt - the Evil Demon
VP