Combining Texts

All the ideas for 'Identity and Spatio-Temporal Continuity', 'Intro to I: Classical Logic' and 'The Problem of Possibilia'

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4 ideas

5. Theory of Logic / A. Overview of Logic / 6. Classical Logic

9463	Classical logic is bivalent, has excluded middle, and only quantifies over existent objects [Jacquette]
	Full Idea: Classical logic (of Whitehead, Russell, Gödel, Church) is a two-valued system of propositional and predicate logic, in which all propositions are exclusively true or false, and quantification and predication are over existent objects only.
	From: Dale Jacquette (Intro to I: Classical Logic [2002], p.9)
	A reaction: All of these get challenged at some point, though the existence requirement is the one I find dubious.

9. Objects / A. Existence of Objects / 5. Individuation / e. Individuation by kind

13128	'Ultimate sortals' cannot explain ontological categories [Westerhoff on Wiggins]
	Full Idea: 'Ultimate sortals' are said to be non-subordinated, disjoint from one another, and uniquely paired with each object. Because of this, the ultimate sortal cannot be a satisfactory explication of the notion of an ontological category.
	From: comment on David Wiggins (Identity and Spatio-Temporal Continuity [1971], p.75) by Jan Westerhoff - Ontological Categories §26
	A reaction: My strong intuitions are that Wiggins is plain wrong, and Westerhoff gives the most promising reasons for my intuition. The simplest point is that objects can obviously belong to more than one category.

10. Modality / B. Possibility / 1. Possibility

9212	Possible states of affairs are not propositions; a proposition can't be a state of affairs! [Fine,K]
	Full Idea: Possible states of affairs have often been taken to be propositions, but this cannot be correct, since any possible state of affairs is possibly a state of affairs, but no proposition is possibly a state of affairs.
	From: Kit Fine (The Problem of Possibilia [2003], 2)
	A reaction: The point is, presumably, that the state of affairs cannot be the proposition itself, but (at least) what the proposition refers to. I can't see any objection to that.

10. Modality / E. Possible worlds / 2. Nature of Possible Worlds / a. Nature of possible worlds

9213	The actual world is a possible world, so we can't define possible worlds as 'what might have been' [Fine,K]
	Full Idea: A possible world can't be defined (by Stalnaker and Plantinga) as a way the world might have been, because a possible world is possibly the world, yet no way the world might have been is possibly the world.
	From: Kit Fine (The Problem of Possibilia [2003], 2)
	A reaction: His point is that any definition of a possible world must cover the actual world, because that is one of them. 'Might have been' is not applicable to the actual world. It seems a fairly important starting point for discussion of possible worlds.