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Single Idea 12208

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

Full Idea

Validity is governed by epistemic necessity, i.e. an argument is valid if and only if there is an a priori route from premises to conclusion.

Gist of Idea

An argument is only valid if it is epistemically (a priori) necessary

Source

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

A Reaction

Controversial, and criticised by McFetridge and Rumfitt. I don't think I agree with her. I don't see validity as depending on dim little human beings.

The 28 ideas from Dorothy Edgington

13764 Are conditionals truth-functional - do the truth values of A and B determine the truth value of 'If A, B'? [Edgington]
13765 'If A,B' must entail ¬(A & ¬B); otherwise we could have A true, B false, and If A,B true, invalidating modus ponens [Edgington]
13768 Validity can preserve certainty in mathematics, but conditionals about contingents are another matter [Edgington]
13770 There are many different conditional mental states, and different conditional speech acts [Edgington]
14270 Simple indicatives about past, present or future do seem to form a single semantic kind [Edgington]
14269 Maybe forward-looking indicatives are best classed with the subjunctives [Edgington]
14274 Inferring conditionals from disjunctions or negated conjunctions gives support to truth-functionalism [Edgington]
14271 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]
14272 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]
14273 Conditional Proof is only valid if we accept the truth-functional reading of 'if' [Edgington]
14276 The truth-functional view makes conditionals with unlikely antecedents likely to be true [Edgington]
14275 Truth-function problems don't show up in mathematics [Edgington]
14278 Truth-functionalists support some conditionals which we assert, but should not actually believe [Edgington]
14282 On the supposition view, believe if A,B to the extent that A&B is nearly as likely as A [Edgington]
14281 A thing works like formal probability if all the options sum to 100% [Edgington]
14284 Conclusion improbability can't exceed summed premise improbability in valid arguments [Edgington]
14287 Does 'If A,B' say something different in each context, because of the possibiites there? [Edgington]
14290 Doctor:'If patient still alive, change dressing'; Nurse:'Either dead patient, or change dressing'; kills patient! [Edgington]
13855 A conditional does not have truth conditions [Edgington]
13853 It is a mistake to think that conditionals are statements about how the world is [Edgington]
13854 Conditionals express what would be the outcome, given some supposition [Edgington]
13857 Truth-functional possibilities include the irrelevant, which is a mistake [Edgington]
13859 X believes 'if A, B' to the extent that A & B is more likely than A & ¬B [Edgington]
12185 Logical necessity is epistemic necessity, which is the old notion of a priori [Edgington, by McFetridge]
12207 Metaphysical possibility is discovered empirically, and is contrained by nature [Edgington]
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]
12205 There are two families of modal notions, metaphysical and epistemic, of equal strength [Edgington]