it's still 'the Earth' we're talking about. — StreetlightX
The importance of Kripke's intervention though (imo) has to do with the way in which he tackles questions of modality - that is, necessity and contingency with respecting to naming. For Kripke, a name is necessary - but this necessity is itself contingent (upon what he calls a primal baptism). It's no accident that Kripke more or less invented modal logic. — StreetlightX
it is necessarily true that this is Earth - by virtue of it being called that — StreetlightX
To clarify, necessity here qualifies truth - it is necessarily true that this is Earth - by virtue of it being called that. I'm not sure what it means to speak of "a particular exist[ing] in the way that it does", so I can't really comment on that. Again, naming, not 'existence', is at issue. — StreetlightX
Rigid designators name some existant, no? They refer to some particular thing - a thing that exists in all possible worlds. — numberjohnny5
If my parents never had children then I would never have been born. The term "I" here is a rigid designator that either refers to a person who doesn't exist in the possible world in which my parents never had children, or doesn't refer to anything in that possible world. — Michael
So in the possible worlds where you don't exist, all the rigid designator is doing is acknowledging ¬(A=A), — numberjohnny5
Hmm, I'd say the theory is 'existent-neutral' though: it applies to Pegasus no less than it applies to the Eiffel Tower. But perhaps I'm using the word 'existent' in a different way than you. Perhaps a counter question to understand where you're coming from better: what matter if the law of identity is acknowledged or not? Like, what difference does that difference make? — StreetlightX
Wait, it wouldn't be denying identity in those possible worlds. — Terrapin Station
~(A=A) would be conventionally read as negating identity in general. Rather you'd be saying something like (∃w) (~A) & (A-->(A=A)) . . . Although that last part should be more along the lines of "insofar as there is A in any world, then . . ." but there's no way to formalize that that I known of. — Terrapin Station
The law of identity matters in virtue of this discussion because if it didn't obtain the concept of "rigid designator" wouldn't be useful. Rigid designators only work if the law of identity obtains, — numberjohnny5
I still don't understand your conditional: "if the law of identity didn't obtain the RD wouldn't be useful"... But useful for what? — StreetlightX
So... If the law of identity didn't obtain, the concept of the rigid designator wouldn't be useful as a signpost that the law of identity obtains? — StreetlightX
Necessity qualifies truth. — StreetlightX
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