Combining Texts

All the ideas for 'Conditionals', 'Ontological Ground of Alethic Modality' and 'Ancient Thought in Modern Physics'

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6 ideas

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.
10. Modality / E. Possible worlds / 1. Possible Worlds / e. Against possible worlds
9220 Lewis must specify that all possibilities are in his worlds, making the whole thing circular [Shalkowski, by Sider]
     Full Idea: If purple cows are simply absent from Lewis's multiverse, then certain correct propositions turn out to be impossible. Lewis must require a world for every possibility. But then it is circular, as the multiverse needs modal notions to characterize it.
     From: report of Scott Shalkowski (Ontological Ground of Alethic Modality [1994], 3.9) by Theodore Sider - Reductive Theories of Modality 3.9
     A reaction: [Inversely, a world containing a round square would make that possible] This sounds very nice, though Sider rejects it (p.197). I've never seen how you could define possibility using the concept of 'possible' worlds.
14. Science / D. Explanation / 2. Types of Explanation / j. Explanations by reduction
6552 You can only explain the qualities of large objects using entities which lack those qualities [Heisenberg]
     Full Idea: It is impossible to explain the manifest qualities of ordinary middle-sized objects except by tracing these back to the behaviour of entities which themselves no longer possess these qualities.
     From: Werner Heisenberg (Ancient Thought in Modern Physics [1937], p.119), quoted by William Lycan - Consciousness 8.10
     A reaction: Compare the similar wonderful remark by Lucretius (Idea 5713). If we accept this as a general principle for all of nature (including us) - and I do - then it is silly to complain that consciousness isn't found in basic physics.