display all the ideas for this combination of texts
6 ideas
| 8969 | We should abandon absolute identity, confining it to within some category [Geach, by Hawthorne] |
| Full Idea: Geach argued that the notion of absolute identity should be abandoned. ..We can only grasp the meaning of a count noun when we associate it with a criterion of identity, expressed by a particular relative identity sortal. | |
| From: report of Peter Geach (Reference and Generality (3rd ed) [1980]) by John Hawthorne - Identity | |
| A reaction: In other words, identity needs categorisation. Hawthorne concludes that Geach is wrong. Geach clearly has much common usage on his side. 'What's that?' usually invites a categorisation. Sameness of objects seems to need a 'respect'. |
| 16058 | Dion and Theon coexist, but Theon lacks a foot. If Dion loses a foot, he ousts Theon? [Chrysippus, by Philo of Alexandria] |
| Full Idea: If two individuals occupied one substance …let one individual (Dion) be thought of as whole-limbed, the other (Theon) as minus one foot. Then let one of Dion's feet be amputated. Theon is the stronger candidate to have perished. | |
| From: report of Chrysippus (fragments/reports [c.240 BCE]) by Philo (Alex) - On the Eternity of the World 48 | |
| A reaction: [SVF 2.397 - from Chrysippus's lost 'On the Growing Argument'] This is the original of Tibbles the Cat. Dion must persist to change, and then ousts Theon (it seems). Philo protests at Theon ceasing to exist when nothing has happened to him. |
| 16059 | Change of matter doesn't destroy identity - in Dion and Theon change is a condition of identity [Chrysippus, by Long/Sedley] |
| Full Idea: The Growing Argument said any change of matter is a change of identity. Chrysippus presents it with a case (Dion and Theon) where material diminution is the necessary condition of enduring identity, since the diminished footless Dion survives. | |
| From: report of Chrysippus (fragments/reports [c.240 BCE]) by AA Long / DN Sedley - Hellenic Philosophers commentary 28:175 | |
| A reaction: [The example, in Idea 16058, is the original of Tibbles the Cat] This is a lovely bold idea which I haven't met in the modern discussions - that identity actually requires change. The concept of identity is meaningless without change? |
| 16075 | Denial of absolute identity has drastic implications for logic, semantics and set theory [Wasserman on Geach] |
| Full Idea: Geach's denial of absolute identity has drastic implications for logic, semantics and set theory. He must deny the axiom of extensionality in set theory, for example. | |
| From: comment on Peter Geach (Reference and Generality (3rd ed) [1980]) by Ryan Wasserman - Material Constitution 6 | |
| A reaction: I'm beginning to think we have two entirely different concepts here - the logicians' and mathematicians' notion of when two things are identical, and the ordinary language concept of two things being 'the same'. 'We like the same music'. |
| 12152 | Identity is relative. One must not say things are 'the same', but 'the same A as' [Geach] |
| Full Idea: Identity is relative. When one says 'x is identical with y' this is an incomplete expression. It is short for 'x is the same A as y', where 'A' represents some count noun understood from the context of utterance. | |
| From: Peter Geach (Reference and Generality (3rd ed) [1980], p.39), quoted by John Perry - The Same F I | |
| A reaction: Perry notes that Geach's view is in conscious opposition to Frege, who had a pure notion of identity. We say 'they are the same insofar as they are animals', but not 'they are the same animal'. Perfect identity involves all possible A's. |
| 16073 | Leibniz's Law is incomplete, since it includes a non-relativized identity predicate [Geach, by Wasserman] |
| Full Idea: Geach rejects the standard formulation of Leibniz's Law as incomplete, since it includes a non-relativized identity predicate. | |
| From: report of Peter Geach (Reference and Generality (3rd ed) [1980]) by Ryan Wasserman - Material Constitution 6 | |
| A reaction: Not many people accept Geach's premiss that identity is a relative matter. I agree with Wiggins on this, that identity is an absolute (and possibly indefinable). The problem with the Law is what you mean by a 'property'. |