18 ideas
| 8952 | We reach 'reflective equilibrium' when intuitions and theory completely align [Fisher] |
| Full Idea: A state of 'reflective equilibrium' is when our theory and our intuitions become completely aligned | |
| From: Jennifer Fisher (On the Philosophy of Logic [2008], 12.IV) | |
| A reaction: [Rawls made this concept famous] This is a helpful concept in trying to spell out the ideal which is the dream of believers in 'pure reason' - that there is a goal in which everything comes right. The problem is when people have different intuitions! |
| 15787 | Maybe Ockham's Razor is a purely aesthetic principle [Lycan] |
| Full Idea: It might be said that Ockham's Razor is a purely aesthetic principle. | |
| From: William Lycan (The Trouble with Possible Worlds [1979], 02) | |
| A reaction: I don't buy this, if it meant to be dismissive of the relevance of the principle to truth. A deep question might be, what is so aesthetically attractive about simplicity? I'm inclined to think that application of the Razor has delivered terrific results. |
| 15784 | The Razor seems irrelevant for Meinongians, who allow absolutely everything to exist [Lycan] |
| Full Idea: A Meinongian has already posited everything that could, or even could not, be; how, then, can any subsequent brandishing of Ockham's Razor be to the point? | |
| From: William Lycan (The Trouble with Possible Worlds [1979], 02) | |
| A reaction: See the ideas of Alexius Meinong. Presumably these crazy Meinongians must make some distinction between what actually exists in front of your nose, and the rest. So the Razor can use that distinction too. |
| 8943 | Three-valued logic says excluded middle and non-contradition are not tautologies [Fisher] |
| Full Idea: In three-valued logic (L3), neither the law of excluded middle (p or not-p), nor the law of non-contradiction (not(p and not-p)) will be tautologies. If p has the value 'indeterminate' then so will not-p. | |
| From: Jennifer Fisher (On the Philosophy of Logic [2008], 07.I) | |
| A reaction: I quite accept that the world is full of indeterminate propositions, and that excluded middle and non-contradiction can sometimes be uncertain, but I am reluctant to accept that what is being offered here should be called 'logic'. |
| 8945 | Fuzzy logic has many truth values, ranging in fractions from 0 to 1 [Fisher] |
| Full Idea: In fuzzy logic objects have properties to a greater or lesser degree, and truth values are given as fractions or decimals, ranging from 0 to 1. Not-p is defined as 1-p, and other formula are defined in terms of maxima and minima for sets. | |
| From: Jennifer Fisher (On the Philosophy of Logic [2008], 07.II) | |
| A reaction: The question seems to be whether this is actually logic, or a recasting of probability theory. Susan Haack attacks it. If logic is the study of how truth is preserved as we move between propositions, then 0 and 1 need a special status. |
| 8951 | Classical logic is: excluded middle, non-contradiction, contradictions imply all, disjunctive syllogism [Fisher] |
| Full Idea: For simplicity, we can say that 'classical logic' amounts to the truth of four sentences: 1) either p or not-p; 2) it is not the case that both p and not-p; 3) from p and not-p, infer q; 4) from p or q and not-p, infer q. | |
| From: Jennifer Fisher (On the Philosophy of Logic [2008], 12.I) | |
| A reaction: [She says there are many ways of specifying classical logic] Intuition suggests that 2 and 4 are rather hard to dispute, while 1 is ignoring some grey areas, and 3 is totally ridiculous. There is, of course, plenty of support for 3! |
| 8950 | Logic formalizes how we should reason, but it shouldn't determine whether we are realists [Fisher] |
| Full Idea: Even if one is inclined to be a realist about everything, it is hard to see why our logic should be the determiner. Logic is supposed to formalize how we ought to reason, but whether or not we should be realists is a matter of philosophy, not logic. | |
| From: Jennifer Fisher (On the Philosophy of Logic [2008], 09.I) | |
| A reaction: Nice to hear a logician saying this. I do not see why talk in terms of an object is a commitment to its existence. We can discuss the philosopher's stone, or Arthur's sword, or the Loch Ness monster, or gravitinos, with degrees of commitment. |
| 8946 | We could make our intuitions about heaps precise with a million-valued logic [Fisher] |
| Full Idea: We could construct a 1,000,000-valued logic that would allow our intuitions concerning a heap to vary exactly with the amount of sand in the heap. | |
| From: Jennifer Fisher (On the Philosophy of Logic [2008]) | |
| A reaction: Presumably only an infinite number of grains of sand would then produce a true heap, and even one grain would count as a bit of a heap, which must both be wrong, so I can't see this helping much. |
| 15792 | Maybe non-existent objects are sets of properties [Lycan] |
| Full Idea: Meinong's Objects have sometimes been construed as sets of properties. | |
| From: William Lycan (The Trouble with Possible Worlds [1979], 09) | |
| A reaction: [Lycan cites Castaņeda and T.Parsons] You still seem to have the problem with any 'bundle' theory of anything. A non-existent object is as much intended to be an object as anything on my desk right now. It just fails to be. |
| 8944 | Vagueness can involve components (like baldness), or not (like boredom) [Fisher] |
| Full Idea: Vague terms come in at least two different kinds: those whose constituent parts come in discrete packets (bald, rich, red) and those that don't (beauty, boredom, niceness). | |
| From: Jennifer Fisher (On the Philosophy of Logic [2008], 07.II) | |
| A reaction: The first group seem to be features of the external world, and the second all occur in the mind. Baldness may be vague, but presumably hairs are (on the whole) not. Nature doesn't care whether someone is actually 'bald' or not. |
| 8941 | We can't explain 'possibility' in terms of 'possible' worlds [Fisher] |
| Full Idea: Explaining 'it is possible that p' by saying p is true in at least one possible world doesn't get me very far. If I don't understand what possibility is, then appealing to possible worlds is not going to do me much good. | |
| From: Jennifer Fisher (On the Philosophy of Logic [2008], 06.III) | |
| A reaction: This seems so blatant that I assume friends of possible worlds will have addressed the problem. Note that you will also need to understand 'possible' to define necessity as 'true in all possible worlds'. Necessarily-p is not-possibly-not-p. |
| 8947 | If all truths are implied by a falsehood, then not-p might imply both q and not-q [Fisher] |
| Full Idea: If all truths are implied by a falsehood, then 'if there are no trees in the park then there is no shade' and 'if there are no trees in the park there is plenty of shade' both come out as true. Intuitively, though, the second one is false. | |
| From: Jennifer Fisher (On the Philosophy of Logic [2008], 08.I) | |
| A reaction: The rule that a falsehood implies all truths must be the weakest idea in classical logic, if it actually implies a contradiction. This means we must take an interest in relevance logics. |
| 8949 | In relevance logic, conditionals help information to flow from antecedent to consequent [Fisher] |
| Full Idea: A good account of relevance logic suggests that a conditional will be true when the flow of information is such that a conditional is the device that helps information to flow from the antecedent to the consequent. | |
| From: Jennifer Fisher (On the Philosophy of Logic [2008], 08.III) | |
| A reaction: Hm. 'If you are going out, you'll need an umbrella'. This passes on information about 'out', but also brings in new information. 'If you are going out, I'm leaving you'. What flows is an interpretation of the antecedent. Tricky. |
| 15795 | Treating possible worlds as mental needs more actual mental events [Lycan] |
| Full Idea: A mentalistic approach to possible worlds is daunted by the paucity of actual mental events. | |
| From: William Lycan (The Trouble with Possible Worlds [1979], 09) | |
| A reaction: Why do they have to be actual, any more than memories have to be conscious? The mental events just need to be available when you need them. They are never all required simultaneously. This isn't mathematical logic! |
| 15796 | Possible worlds must be made of intensional objects like propositions or properties [Lycan] |
| Full Idea: I believe the only promising choice of actual entities to serve as 'worlds' is that of sets of intensional objects, such as propositions or properties with stipulated interrelations. | |
| From: William Lycan (The Trouble with Possible Worlds [1979], 12) | |
| A reaction: This is mainly in response to Lewis's construction of them out of actual concrete objects. It strikes me as a bogus problem. It is just a convenient way to think precisely about possibilities, and occasionally outruns our mental capacity. |
| 15794 | If 'worlds' are sentences, and possibility their consistency, consistency may rely on possibility [Lycan] |
| Full Idea: If a 'world' is understood as a set of sentences, then possibility may be understood as consistency, ...but this seems circular, in that 'consistency' of sentences cannot adequately be defined save in terms of possibility. | |
| From: William Lycan (The Trouble with Possible Worlds [1979], 09) | |
| A reaction: [Carnap and Hintikka propose the view, Lewis 'Counterfactuals' p.85 objects] Worlds as sentences is not, of course, the same as worlds as propositions. There is a lot of circularity around in 'possible' worlds. |
| 19679 | 'Access' internalism says responsibility needs access; weaker 'mentalism' needs mental justification [Kvanvig] |
| Full Idea: Strong 'access' internalism says the justification must be accessible to the person holding the belief (for cognitive duty, or blame), and weaker 'mentalist' internalism just says the justification must supervene on mental features of the individual. | |
| From: Jonathan Kvanvig (Epistemic Justification [2011], III) | |
| A reaction: [compressed] I think I'm a strong access internalist. I doubt whether there is a correct answer to any of this, but my conception of someone knowing something involves being able to invoke their reasons for it. Even if they forget the source. |
| 19678 | Strong foundationalism needs strict inferences; weak version has induction, explanation, probability [Kvanvig] |
| Full Idea: Strong foundationalists require truth-preserving inferential links between the foundations and what the foundations support, while weaker versions allow weaker connections, such as inductive support, or best explanation, or probabilistic support. | |
| From: Jonathan Kvanvig (Epistemic Justification [2011], II) | |
| A reaction: [He cites Alston 1989] Personally I'm a coherentist about justification, but I'm a fan of best explanation, so I'd vote for that. It's just that best explanation is not a very foundationalist sort of concept. Actually, the strong version is absurd. |