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Single Idea 12206

[filed under theme 10. Modality / A. Necessity / 6. Logical Necessity ]

Full Idea

So-called broadly logical necessity (by which I mean, not necessarily formal logical necessity) is an epistemic notion.

Gist of Idea

Broadly logical necessity (i.e. not necessarily formal logical necessity) is an epistemic notion

Source

Dorothy Edgington (Two Kinds of Possibility [2004], §I)


A Reaction

This is controversial, and is criticised by McFetridge and Rumfitt. Fine argues that 'narrow' (formal) logical necessity is metaphysical. Between them they have got rid of logical necessity completely.


The 28 ideas from Dorothy Edgington

Are conditionals truth-functional - do the truth values of A and B determine the truth value of 'If A, B'? [Edgington]
'If A,B' must entail ¬(A & ¬B); otherwise we could have A true, B false, and If A,B true, invalidating modus ponens [Edgington]
Validity can preserve certainty in mathematics, but conditionals about contingents are another matter [Edgington]
There are many different conditional mental states, and different conditional speech acts [Edgington]
Simple indicatives about past, present or future do seem to form a single semantic kind [Edgington]
Maybe forward-looking indicatives are best classed with the subjunctives [Edgington]
Inferring conditionals from disjunctions or negated conjunctions gives support to truth-functionalism [Edgington]
Non-truth-functionalist say 'If A,B' is false if A is T and B is F, but deny that is always true for TT,FT and FF [Edgington]
I say "If you touch that wire you'll get a shock"; you don't touch it. How can that make the conditional true? [Edgington]
Conditional Proof is only valid if we accept the truth-functional reading of 'if' [Edgington]
The truth-functional view makes conditionals with unlikely antecedents likely to be true [Edgington]
Truth-function problems don't show up in mathematics [Edgington]
Truth-functionalists support some conditionals which we assert, but should not actually believe [Edgington]
On the supposition view, believe if A,B to the extent that A&B is nearly as likely as A [Edgington]
A thing works like formal probability if all the options sum to 100% [Edgington]
Conclusion improbability can't exceed summed premise improbability in valid arguments [Edgington]
Does 'If A,B' say something different in each context, because of the possibiites there? [Edgington]
Doctor:'If patient still alive, change dressing'; Nurse:'Either dead patient, or change dressing'; kills patient! [Edgington]
A conditional does not have truth conditions [Edgington]
It is a mistake to think that conditionals are statements about how the world is [Edgington]
Conditionals express what would be the outcome, given some supposition [Edgington]
Truth-functional possibilities include the irrelevant, which is a mistake [Edgington]
X believes 'if A, B' to the extent that A & B is more likely than A & ¬B [Edgington]
Logical necessity is epistemic necessity, which is the old notion of a priori [Edgington, by McFetridge]
Metaphysical possibility is discovered empirically, and is contrained by nature [Edgington]
Broadly logical necessity (i.e. not necessarily formal logical necessity) is an epistemic notion [Edgington]
An argument is only valid if it is epistemically (a priori) necessary [Edgington]
There are two families of modal notions, metaphysical and epistemic, of equal strength [Edgington]