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Single Idea 12180
[filed under theme 10. Modality / A. Necessity / 6. Logical Necessity
]
Full Idea
There will be a legitimate notion of 'logical' necessity only if there is a notion of necessity which attaches to the claim, concerning a deductively valid argument, that if the premisses are true then so is the conclusion.
Gist of Idea
Logical necessity requires that a valid argument be necessary
Source
Ian McFetridge (Logical Necessity: Some Issues [1986], §1)
Book Ref
-: 'Aristotelian Society' [], p.136
A Reaction
He quotes Aristotle's Idea 11148 in support. Is this resting a stronger idea on a weaker one? Or is it the wrong way round? We endorse validity because we see the necessity; we don't endorse necessity because we see 'validity'.
Related Idea
Idea 11148
Deduction is when we suppose one thing, and another necessarily follows [Aristotle]
The
40 ideas
with the same theme
[necessity because of logic or definitions]:
17852
|
A thing has a feature necessarily if its denial brings a contradiction
[Aristotle]
|
12259
|
Reasoning is when some results follow necessarily from certain claims
[Aristotle]
|
16490
|
Some facts about experience feel like logical necessities
[Russell]
|
9001
|
Frege moved Kant's question about a priori synthetic to 'how is logical certainty possible?'
[Quine]
|
12188
|
Contrary to some claims, Quine does not deny logical necessity
[Quine, by McFetridge]
|
15230
|
Logical necessity is grounded in the logical form of a statement
[Harré/Madden]
|
13820
|
The idea that anything which can be proved is necessary has a problem with empty names
[Bostock]
|
15083
|
The fundamental case of logical necessity is the valid conclusion of an inference
[McFetridge, by Hale]
|
15084
|
In the McFetridge view, logical necessity means a consequent must be true if the antecedent is
[McFetridge, by Hale]
|
12181
|
Traditionally, logical necessity is the strongest, and entails any other necessities
[McFetridge]
|
12180
|
Logical necessity requires that a valid argument be necessary
[McFetridge]
|
12183
|
It is only logical necessity if there is absolutely no sense in which it could be false
[McFetridge]
|
12184
|
Logical necessity overrules all other necessities
[McFetridge]
|
12192
|
The mark of logical necessity is deduction from any suppositions whatever
[McFetridge]
|
12189
|
Logical necessity involves a decision about usage, and is non-realist and non-cognitive
[Wright,C, by McFetridge]
|
14681
|
Logical necessity is free of constraints, and may accommodate all of S5 logic
[Salmon,N]
|
13394
|
Entailment does not result from mutual necessity; mutual necessity ensures entailment
[Jubien]
|
12185
|
Logical necessity is epistemic necessity, which is the old notion of a priori
[Edgington, by McFetridge]
|
10258
|
Logical modalities may be acceptable, because they are reducible to satisfaction in models
[Shapiro]
|
15417
|
Logical necessity has two sides - validity and demonstrability - which coincide in classical logic
[Burgess]
|
15419
|
General consensus is S5 for logical modality of validity, and S4 for proof
[Burgess]
|
12206
|
Broadly logical necessity (i.e. not necessarily formal logical necessity) is an epistemic notion
[Edgington]
|
12208
|
An argument is only valid if it is epistemically (a priori) necessary
[Edgington]
|
8260
|
Logical necessity can be 'strict' (laws), or 'narrow' (laws and definitions), or 'broad' (all logical worlds)
[Lowe]
|
16973
|
Explain logical necessity by logical consequence, or the other way around?
[Correia]
|
15085
|
'Broadly' logical necessities are derived (in a structure) entirely from the concepts
[Hale]
|
15088
|
Logical necessities are true in virtue of the nature of all logical concepts
[Hale]
|
13709
|
Logical truths must be necessary if anything is
[Sider]
|
19285
|
Logical necessity is something which is true, no matter what else is the case
[Hale]
|
19287
|
Maybe each type of logic has its own necessity, gradually becoming broader
[Hale]
|
18848
|
Something may be necessary because of logic, but is that therefore a special sort of necessity?
[Rosen]
|
9481
|
Logical necessitation is not a kind of necessity; George Orwell not being Eric Blair is not a real possibility
[Bird]
|
18478
|
Wittgenstein's plan to show there is only logical necessity failed, because of colours
[MacBride]
|
11084
|
Logical necessity is truth in all logically possible worlds, because of laws and concepts
[Hanna]
|
16042
|
The metaphysically and logically possible worlds are the same, so they are the same strength
[Bennett,K]
|
22150
|
Logical possibility needs the concepts of the proposition to be adequate
[Boulter]
|
18825
|
S5 is the logic of logical necessity
[Rumfitt]
|
12193
|
Logical necessity is when 'necessarily A' implies 'not-A is contradictory'
[Rumfitt]
|
12200
|
A logically necessary statement need not be a priori, as it could be unknowable
[Rumfitt]
|
12202
|
Narrow non-modal logical necessity may be metaphysical, but real logical necessity is not
[Rumfitt]
|