Combining Texts

All the ideas for 'Conditionals', 'Papers of 1918' and 'Mathematics and Indispensibility'

unexpand these ideas     |    start again     |     specify just one area for these texts

---

6 ideas

7. Existence / D. Theories of Reality / 11. Ontological Commitment / e. Ontological commitment problems

9558	All scientific tests will verify mathematics, so it is a background, not something being tested [Sober]
	Full Idea: If mathematical statements are part of every competing hypothesis, then no matter which hypothesis comes out best in the light of observations, they will be part of the best hypothesis. They are not tested, but are a background assumption.
	From: Elliott Sober (Mathematics and Indispensibility [1993], 45), quoted by Charles Chihara - A Structural Account of Mathematics
	A reaction: This is a very nice objection to the Quine-Putnam thesis that mathematics is confirmed by the ongoing successes of science.

10. Modality / B. Possibility / 8. Conditionals / a. Conditionals

13768	Validity can preserve certainty in mathematics, but conditionals about contingents are another matter [Edgington]
	Full Idea: If your interest in logic is confined to applications to mathematics or other a priori matters, it is fine for validity to preserve certainty, ..but if you use conditionals when arguing about contingent matters, then great caution will be required.
	From: Dorothy Edgington (Conditionals [2001], 17.2.1)

10. Modality / B. Possibility / 8. Conditionals / b. Types of conditional

13770	There are many different conditional mental states, and different conditional speech acts [Edgington]
	Full Idea: As well as conditional beliefs, there are conditional desires, hopes, fears etc. As well as conditional statements, there are conditional commands, questions, offers, promises, bets etc.
	From: Dorothy Edgington (Conditionals [2001], 17.3.4)

10. Modality / B. Possibility / 8. Conditionals / c. Truth-function conditionals

13764	Are conditionals truth-functional - do the truth values of A and B determine the truth value of 'If A, B'? [Edgington]
	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'?
	From: Dorothy Edgington (Conditionals [2001], 17.1)
	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.

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]
	Full Idea: If it were possible to have A true, B false, and If A,B true, it would be unsafe to infer B from A and If A,B: modus ponens would thus be invalid. Hence 'If A,B' must entail ¬(A & ¬B).
	From: Dorothy Edgington (Conditionals [2001], 17.1)
	A reaction: This is a firm defence of part of the truth-functional view of conditionals, and seems unassailable. The other parts of the truth table are open to question, though, if A is false, or they are both true.

19. Language / D. Propositions / 4. Mental Propositions

22307	Propositions don't name facts, because two opposed propositions can match one fact [Russell]
	Full Idea: It is perfectly evident that a proposition is not the name for a fact, from the mere circumstance that there are two propositions corresponding to each fact. 'Socrates is dead' and 'Socrates is not dead' correspond to the same fact.
	From: Bertrand Russell (Papers of 1918 [1918], VIII.136), quoted by Michael Potter - The Rise of Analytic Philosophy 1879-1930 42 'Prop'
	A reaction: He finally reaches in 1918 what now looks fairly obvious. The idea that a proposition is part of the world is absurd. We should call the parts of the world 'facts' (despite vagueness and linguistic dependence in such things). Propositions are thoughts.