20 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. |
| 19216 | Propositions (such as 'that dog is barking') only exist if their items exist [Williamson] |
| Full Idea: A proposition about an item exists only if that item exists... how could something be the proposition that that dog is barking in circumstances in which that dog does not exist? | |
| From: Timothy Williamson (Necessary Existents [2002], p.240), quoted by Trenton Merricks - Propositions | |
| A reaction: This is a view of propositions I can't make sense of. If I'm under an illusion that there is a dog barking nearby, when there isn't one, can I not say 'that dog is barking'? If I haven't expressed a proposition, what have I done? |
| 23418 | Liberal state legitimacy is based on a belief in justice, not in some conception of the good life [Kymlicka] |
| Full Idea: For liberals the basis of state legitimacy is a shared sense of justice, not a shared conception of the good. | |
| From: Will Kymlicka (Community [1993], 'legitimacy') | |
| A reaction: For a liberal state to work, the citizens have to roughly believe in the core values of liberalism, which are primarily freedom and equality (and hence justice). |
| 23414 | Liberals say state intervention in culture restricts people's autonomy [Kymlicka] |
| Full Idea: According to liberal theory, a state which intervenes in the cultural market place to encourage any particular way of life restricts people's autonomy. | |
| From: Will Kymlicka (Community [1993], 'social') | |
| A reaction: The communitarian idea is that the state should intervene, in order to foster the best aspects of communal culture. The dangers are obvious, and can be seen in any totalitarian state. A gentle hand on the tiller, perhaps? Increase the options? |
| 23410 | Modern liberals see a community as simply a society which respects freedom and equality [Kymlicka] |
| Full Idea: Most contemporary liberal philosophers have little to say about the ideal of community. …It is often seen as derivative of liberty and equality - a society lives up to the ideal of community if its members are treated as free and equal persons. | |
| From: Will Kymlicka (Community [1993], 'Intro') | |
| A reaction: He cites Rawls as an example. This is the central idea which was attacked by modern communitarians. A collection of scattered self-seeking isolated individuals doesn't seem to amount to a healthy communal life. Maybe community needs further rights? |
| 23409 | Community can focus on class or citizenship or ethnicity or culture [Kymlicka] |
| Full Idea: In recent centuries the ideal of community has taken many forms, from class solidarity or shared citizenship to a common ethnic descent or cultural identity. | |
| From: Will Kymlicka (Community [1993], 'Intro') | |
| A reaction: Language and religion are not explicitly mentioned, but must be implied. Supporting a major sports team is also worth mentioning. |
| 23419 | Communitarianism struggles with excluded marginalised groups [Kymlicka] |
| Full Idea: The problem of the exclusion of historically marginalised groups is endemic to the communitarian project. | |
| From: Will Kymlicka (Community [1993], 'legitimacy') | |
| A reaction: Put simply, old-fashioned styles of community are probably impossible in large modern states, some with rather arbitrary borders. |
| 23413 | Feminism has shown that social roles are far from fixed (as communitarians tend to see them) [Kymlicka] |
| Full Idea: Communitarians say that some of our social roles must be regarded as fixed when planning our lives, …but the women's movement has shown how deeply entrenched social roles can be questioned and rejected. | |
| From: Will Kymlicka (Community [1993], 'Embedded') | |
| A reaction: True, but parents walking out on young children also shows that. The ideal must be some sort of balance. |
| 23415 | Participation aids the quest for the good life, but why should that be a state activity? [Kymlicka] |
| Full Idea: Communitarians rarely distinguish between collective activities and political activities. Shared participation aids intelligent decisions about the good life, but why should that be organised through the state, rather than by free individuals? | |
| From: Will Kymlicka (Community [1993], 'need') | |
| A reaction: Kylicka points out later that local groups can be very unintelligent or prejudiced. Modern media have changed that picture, because participation can be with geographically remote people. |
| 23411 | Communitarians see justice as primarily a community matter, rather than a principle [Kymlicka] |
| Full Idea: Communitarians believe either that community replaces the need for principles of justice, or that the community is either the source of such principles or should play a greater role in deciding their content. | |
| From: Will Kymlicka (Community [1993], 'Intro') | |
| A reaction: [compressed] The idea that a racist or chauvinist or puritanical or insular community should decide justice for all its members sounds horrible. It drives you to liberal individualism, just thinking about it. |
| 23412 | Justice resolves conflicts, but may also provoke them [Kymlicka] |
| Full Idea: Justice can help mediate conflicts, but it also tends to creat conflicts, and to decrease the natural expression of sociability. | |
| From: Will Kymlicka (Community [1993], 'limits') | |
| A reaction: [He is discussing Michael Sandel on liberalism] Family life might not go well if all of its members continually demanded justice for themselves as individuals. Maybe our concept of justice is too individualistic? Do we need a sense of 'group' justice? |