15 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! |
| 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. |
| 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. |
| 20440 | Art is a referential activity, hence indefinable, but it has a set of symptoms [Goodman] |
| Full Idea: No definition of art is possible (since it is a referential activity), …but the symptoms of art are syntactic density, semantic density, syntactic repleteness, exemplificationality, and multiple and complex reference. | |
| From: Nelson Goodman (Languages of Art (2nd edn) [1968], p.22-255), quoted by Alessandro Giovannelli - Nelson Goodman (aesthetics) 4 | |
| A reaction: I wish these labels were more self-explanatory. Goodman seems to want to assimilate art to his earlier interests in linguistic anti-realism and mereology. I wouldn't have thought he now had many followers. |
| 20439 | Artistic symbols are judged by the fruitfulness of their classifications [Goodman, by Giovannelli] |
| Full Idea: Artistic symbols are to be judged for the classifications they bring about, for how novel and insightful those classifications are, for how they change our world perceptions and relations. | |
| From: report of Nelson Goodman (Languages of Art (2nd edn) [1968]) by Alessandro Giovannelli - Nelson Goodman (aesthetics) 4 | |
| A reaction: This seems to be an awfully long way from our normal experience of art. I understand 'symbols' in early Flemish art, but not in Mondriaan, or even Rembrandt. |
| 20438 | A performance is only an instance of a work if there is not a single error [Goodman] |
| Full Idea: The most miserable performance without actual mistakes does count as an instance of a work, …but the most brilliant performance with a single wrong note does not. | |
| From: Nelson Goodman (Languages of Art (2nd edn) [1968], p.186), quoted by Alessandro Giovannelli - Nelson Goodman (aesthetics) | |
| A reaction: Mereological essentialism applied to art! You need to be a highly theoretical and technical philosopher (which Goodman was) to maintain such a weird and contrary-usage proposal. |
| 20437 | A copy only becomes an 'instance' of an artwork if there is a system of notation [Goodman] |
| Full Idea: Paintings and sculptures do not work within a notation; hence, there is no copying of an original that would preserve its originality. A copy of a painting is a copy, not an instance of the original. | |
| From: Nelson Goodman (Languages of Art (2nd edn) [1968], p.212), quoted by Alessandro Giovannelli - Nelson Goodman (aesthetics) 2 | |
| A reaction: Sounds conclusive, but isn't. Is a poetry manuscript a 'notation' or an original? Why is an etching plate a notation, but painting on canvas is an original? Can I create a painting specifically so that it can be copied (by my students)? Intention matters. |
| 20740 | Maybe humans are distinguished from other animals by feelings, rather than reason [Unamuno] |
| Full Idea: Man is said to be a reasoning animal. I do not know why he has not been defined as an affective or feeling animal. Perhaps that which differentiates him from other animals is feeling rather than reason. | |
| From: Miguel de Unamuno (The Tragic Sense of Life [1912], p.3), quoted by Kevin Aho - Existentialism: an introduction 2 'Problem' | |
| A reaction: Perfectly plausible, given that we presume that our feelings are startlingly different from other animals - even if we feel far more community with other mammals than we did in Unamuno's day. |