17 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. |
| 22465 | We see a moral distinction between doing and allowing to happen [Foot] |
| Full Idea: We have an intuition that there is a morally relevant distinction between what we do and what we allow to happen. | |
| From: Philippa Foot (Morality, Action, and Outcome [1985], p.88) | |
| A reaction: She says many deny this distinction, but she defends it. Presumably consequentialists deny the distinction. What is bad if I do it, but OK if I allow it to happen? Neglecting a victim to save others, she suggests. |
| 22466 | We see a moral distinction between our aims and their foreseen consequences [Foot] |
| Full Idea: We have an intuition that there is a moral distinction between what we aim at and what we foresee as a result of what we do. | |
| From: Philippa Foot (Morality, Action, and Outcome [1985], p.88) | |
| A reaction: Cf. Idea 22465. This seems to be the classic doctrine of double effect. It is hard to defend the claim that we are only responsible for what we aim at. A wide assessment of consequences is a moral duty. Well-meaning fools are bad. |
| 22467 | Acts and omissions only matter if they concern doing something versus allowing it [Foot] |
| Full Idea: The difference between acts and omissions is irrelevant to any moral issue except in so far as it corresponds to the distinction between allowing something to happen and being the agent to whom the happening can be ascribed. | |
| From: Philippa Foot (Morality, Action, and Outcome [1985], p.89) | |
| A reaction: The list of anyone's omissions is presumably infinite, but what they 'allow' must be in some way within their power. But what of something I can't now prevent, only because I failed to do some relevant task yesterday? |
| 23689 | Moral words have an inherited power from expressing attitudes in emotional situations [Stevenson,CL] |
| Full Idea: A term is moral because of the power that the word acquires, on account of its history in emotional situations, to evoke or directly express attitudes, as distinct from describing or designating them. | |
| From: Charles Leslie Stevenson (Ethics and Language [1944], p.33), quoted by John Hacker-Wright - Philippa Foot's Moral Thought 1 'Ayer' | |
| A reaction: Invites the question of what the words meant before they acquired this patina of historical usage. If 'good' orginally meant 'hurray!', its repeated usage doesn't seem to change that. If it was descriptive, why would that change with time? |
| 22470 | A good moral system benefits its participants, and so demands reciprocity [Foot] |
| Full Idea: It has been suggested that one criterion for a good moral system is that it should be possible to demand reciprocity from every individual because of the good the system renders to him. | |
| From: Philippa Foot (Morality, Action, and Outcome [1985], p.104) | |
| A reaction: Money seems to have this feature, that we mostly conform to the rules for its use, because we value the whole system. Foot accepts this, but says there are also other criteria, such as leaving freedom to live well (ie. not too puritanical). |
| 22468 | Virtues can have aims, but good states of affairs are not among them [Foot] |
| Full Idea: Some virtues do give us aims, but nothing from within morality suggests the kind of good state of affairs which it would seem always to be our duty to promote. And why indeed should there be any such thing? | |
| From: Philippa Foot (Morality, Action, and Outcome [1985], p.101) | |
| A reaction: Isn't successful human functioning, such as heath, always to be desired? If honour is a worthy aim, doesn't that make being rightly honoured a desirable state of affairs? She is attacking consequentialism, but I'm not convinced here. |
| 22469 | Some virtues imply rules, and others concern attachment [Foot] |
| Full Idea: Virtues such as justice consist mainly in adherence to rules of conduct, while those such as benevolence we might call virtues of attachment. | |
| From: Philippa Foot (Morality, Action, and Outcome [1985], p.101) | |
| A reaction: Not sure about 'attachment'. We should be benevolent towards people to whom we are not particularly attached. Courage doesn't fall into either group. |