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Single Idea 4885

[filed under theme 9. Objects / F. Identity among Objects / 1. Concept of Identity ]

Full Idea

The truth of "a=b" doesn't require much of 'a' and 'b' other than that there is a single thing to which they both refer. They needn't be interdefinable, or have supervenient properties. In this sense, identity is a very weak relation.

Gist of Idea

Identity is a very weak relation, which doesn't require interdefinability, or shared properties

Source

John Perry (Knowledge, Possibility and Consciousness [2001], §1.2)

Book Ref

Perry,John: 'Knowledge, Possibility and Consciousness' [MIT 2001], p.6

A Reaction

Interesting. This is seeing the epistemological aspects of identity. Ontologically, identity must invoke Leibniz's Law, and is the ultimately powerful 'relation'. A given student, and the cause of a crop circle, may APPEAR to be quite different.

The 14 ideas from 'Knowledge, Possibility and Consciousness'

4885 Identity is a very weak relation, which doesn't require interdefinability, or shared properties [Perry]
4884 Brain states must be in my head, and yet the pain seems to be in my hand [Perry]
4887 We try to cause other things to occur by causing mental events to occur [Perry]
4888 It seems plausible that many animals have experiences without knowing about them [Perry]
4889 Although we may classify ideas by content, we individuate them differently, as their content can change [Perry]
4890 A sharp analytic/synthetic line can rarely be drawn, but some concepts are central to thought [Perry]
4891 If epiphenomenalism just says mental events are effects but not causes, it is consistent with physicalism [Perry]
4892 If physicalists stick with identity (not supervenience), Martian pain will not be like ours [Perry]
4896 The intension of an expression is a function from possible worlds to an appropriate extension [Perry]
4897 A proposition is a set of possible worlds for which its intension delivers truth [Perry]
4900 Prior to Kripke, the mind-brain identity theory usually claimed that the identity was contingent [Perry]
4901 Truth has to be correspondence to facts, and a match between relations of ideas and relations in the world [Perry]
4898 Possible worlds are indices for a language, or concrete realities, or abstract possibilities [Perry]
4899 Possible worlds thinking has clarified the logic of modality, but is problematic in epistemology [Perry]