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Single Idea 13764
[filed under theme 10. Modality / B. Possibility / 8. Conditionals / c. Truth-function conditionals
]
Full Idea
Are conditionals truth-functional - do the truth values of A and B determine the truth value of 'If A, B'? Are they non-truth-functional, like 'because' or 'before'? Do the values of A and B, in some cases, leave open the value of 'If A,B'?
Gist of Idea
Are conditionals truth-functional - do the truth values of A and B determine the truth value of 'If A, B'?
Source
Dorothy Edgington (Conditionals [2001], 17.1)
Book Ref
'Blackwell Guide to Philosophical Logic', ed/tr. Goble,Lou [Blackwell 2001], p.386
A Reaction
I would say they are not truth-functional, because the 'if' asserts some further dependency relation that goes beyond the truth or falsity of A and B. Logical ifs, causal ifs, psychological ifs... The material conditional ⊃ is truth-functional.
Related Ideas
Idea 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]
Idea 14309
Truth-functional conditionals can't distinguish whether they are causal or accidental [Mumford]
The
28 ideas
from Dorothy Edgington
13764
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Are conditionals truth-functional - do the truth values of A and B determine the truth value of 'If A, B'?
[Edgington]
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13765
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'If A,B' must entail ¬(A & ¬B); otherwise we could have A true, B false, and If A,B true, invalidating modus ponens
[Edgington]
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13768
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Validity can preserve certainty in mathematics, but conditionals about contingents are another matter
[Edgington]
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13770
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There are many different conditional mental states, and different conditional speech acts
[Edgington]
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14270
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Simple indicatives about past, present or future do seem to form a single semantic kind
[Edgington]
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14269
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Maybe forward-looking indicatives are best classed with the subjunctives
[Edgington]
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14274
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Inferring conditionals from disjunctions or negated conjunctions gives support to truth-functionalism
[Edgington]
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14271
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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]
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14272
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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]
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14273
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Conditional Proof is only valid if we accept the truth-functional reading of 'if'
[Edgington]
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14276
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The truth-functional view makes conditionals with unlikely antecedents likely to be true
[Edgington]
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14275
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Truth-function problems don't show up in mathematics
[Edgington]
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14278
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Truth-functionalists support some conditionals which we assert, but should not actually believe
[Edgington]
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14282
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On the supposition view, believe if A,B to the extent that A&B is nearly as likely as A
[Edgington]
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14281
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A thing works like formal probability if all the options sum to 100%
[Edgington]
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14284
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Conclusion improbability can't exceed summed premise improbability in valid arguments
[Edgington]
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14287
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Does 'If A,B' say something different in each context, because of the possibiites there?
[Edgington]
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14290
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Doctor:'If patient still alive, change dressing'; Nurse:'Either dead patient, or change dressing'; kills patient!
[Edgington]
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13855
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A conditional does not have truth conditions
[Edgington]
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13853
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It is a mistake to think that conditionals are statements about how the world is
[Edgington]
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13854
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Conditionals express what would be the outcome, given some supposition
[Edgington]
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13857
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Truth-functional possibilities include the irrelevant, which is a mistake
[Edgington]
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13859
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X believes 'if A, B' to the extent that A & B is more likely than A & ¬B
[Edgington]
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12185
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Logical necessity is epistemic necessity, which is the old notion of a priori
[Edgington, by McFetridge]
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12207
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Metaphysical possibility is discovered empirically, and is contrained by nature
[Edgington]
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12206
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Broadly logical necessity (i.e. not necessarily formal logical necessity) is an epistemic notion
[Edgington]
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12208
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An argument is only valid if it is epistemically (a priori) necessary
[Edgington]
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12205
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There are two families of modal notions, metaphysical and epistemic, of equal strength
[Edgington]
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