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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

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]