6 ideas
| 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) |
| 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) |
| 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. |
| 15640 | Courage is not a virtue, but the form of every virtue at its testing point [Lewis,CS] |
| Full Idea: Courage is not simply one of the virtues, but the form of every virtue at the testing point. | |
| From: C.S. Lewis (works [1950]) | |
| A reaction: This appeared on Twitter, without mention of its source. Adding it breaks my normal rules, but I hope you agree that it is too good to miss. Is not even resolutely facing up to suffering or death a case of genuine courage? Determination, prioritisation? |
| 8409 | Probabilistic causal concepts are widely used in everyday life and in science [Salmon] |
| Full Idea: Probabilistic causal concepts are used in innumerable contexts of everyday life and science. ...In causes of cancer, road accidents, or food poisoning, for example. | |
| From: Wesley Salmon (Probabilistic Causality [1980], p.137) | |
| A reaction: [Second half compresses his examples] This strikes me as rather a weak point. No one ever thought that a particular road accident was actually caused by the high probability of it at a particular location. Causes are in the mechanisms. |