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Single Idea 19279

[filed under theme 10. Modality / E. Possible worlds / 1. Possible Worlds / a. Possible worlds ]

Full Idea

We need an explanation of what worlds are that makes clear why being true at all of them should be necessary and sufficient for being necessary (and true at one of them suffices for being possible).

Gist of Idea

What are these worlds, that being true in all of them makes something necessary?

Source

Bob Hale (Necessary Beings [2013], 03.3.2)

Book Ref

Hale,Bob: 'Necessary Beings' [OUP 2013], p.71


A Reaction

Hale is introducing combinatorial accounts of worlds, as one possible answer to this. Hale observes that all the worlds might be identical to our world. It is always assumed that the worlds are hugely varied. But maybe worlds are constrained.


The 23 ideas from 'Necessary Beings'

You cannot understand what exists without understanding possibility and necessity [Hale]
The big challenge for essentialist views of modality is things having necessary existence [Hale]
There is no gap between a fact that p, and it is true that p; so we only have the truth-condtions for p [Hale]
What are these worlds, that being true in all of them makes something necessary? [Hale]
Interesting supervenience must characterise the base quite differently from what supervenes on it [Hale]
It seems that we cannot show that modal facts depend on non-modal facts [Hale]
'Absolute necessity' is when there is no restriction on the things which necessitate p [Hale]
Logical necessity is something which is true, no matter what else is the case [Hale]
Maybe each type of logic has its own necessity, gradually becoming broader [Hale]
Logical and metaphysical necessities differ in their vocabulary, and their underlying entities [Hale]
Maybe conventionalism applies to meaning, but not to the truth of propositions expressed [Hale]
Absolute necessities are necessarily necessary [Hale]
A canonical defintion specifies the type of thing, and what distinguish this specimen [Hale]
Essentialism doesn't explain necessity reductively; it explains all necessities in terms of a few basic natures [Hale]
If necessity derives from essences, how do we explain the necessary existence of essences? [Hale]
Add Hume's principle to logic, to get numbers; arithmetic truths rest on the nature of the numbers [Hale]
If second-order variables range over sets, those are just objects; properties and relations aren't sets [Hale]
The two Barcan principles are easily proved in fairly basic modal logic [Hale]
Unlike axiom proofs, natural deduction proofs needn't focus on logical truths and theorems [Hale]
Possible worlds make every proposition true or false, which endorses classical logic [Hale]
The molecules may explain the water, but they are not what 'water' means [Hale]
With a negative free logic, we can dispense with the Barcan formulae [Hale]
If a chair could be made of slightly different material, that could lead to big changes [Hale]