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Single Idea 14357

[filed under theme 10. Modality / B. Possibility / 8. Conditionals / d. Non-truthfunction conditionals ]

Full Idea

In the possible worlds account of conditionals A⊃B is not sufficient for A→B. If A is false then A⊃B is true, but here nothing is implied about whether the world most like the actual world except that A is true is or is not a B-world.

Clarification

⊃ is material implication, equivalent to ¬AvB

Gist of Idea

Possible worlds account, unlike A⊃B, says nothing about when A is false

Source

Frank Jackson (Conditionals [2006], 'Possible')

Book Ref

'Blackwell Guide to Philosophy of Language', ed/tr. Devitt,M/Hanley,R [Blackwell 2006], p.215


A Reaction

The possible worlds account seems to be built on Ramsey's idea of just holding A true and seeing what you get. Being committed to B being automatically true if A is false seems highly counterintuitive.