21 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. |
| 7755 | Singular terms refer, using proper names, definite descriptions, singular personal pronouns, demonstratives, etc. [Lycan] |
| Full Idea: The paradigmatic referring devices are singular terms, denoting particular items. In English these include proper names, definite descriptions, singular personal pronouns, demonstrative pronouns, and a few others. | |
| From: William Lycan (Philosophy of Language [2000], Ch. 1) | |
| A reaction: This list provides the agenda for twentieth century philosophy of language, since this is the point where language is supposed to hook onto the world. |
| 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. |
| 7768 | The truth conditions theory sees meaning as representation [Lycan] |
| Full Idea: The truth conditions theory sees meaning as representation. | |
| From: William Lycan (Philosophy of Language [2000], Ch. 9) | |
| A reaction: This suggests a nice connection to Fodor's account of intentional thinking. The whole package sounds right to me (though the representations need not be 'symbolic', or in mentalese). |
| 7766 | Meaning must be known before we can consider verification [Lycan] |
| Full Idea: How could we know whether a sentence is verifiable unless we already knew what it says? | |
| From: William Lycan (Philosophy of Language [2000], Ch. 8) | |
| A reaction: This strikes me as a devastating objection to verificationism. Lycan suggests that you can formulate a preliminary meaning, without accepting true meaningfulness. Maybe verification just concerns truth, and not meaning. |
| 7764 | Could I successfully use an expression, without actually understanding it? [Lycan] |
| Full Idea: Could I not know the use of an expression and fall in with it, mechanically, but without understanding it? | |
| From: William Lycan (Philosophy of Language [2000], Ch. 6) | |
| A reaction: In a foreign country, you might successfully recite a long complex sentence, without understanding a single word. This doesn't doom the 'use' theory, but it means that quite a lot of detail needs to be filled in. |
| 7763 | It is hard to state a rule of use for a proper name [Lycan] |
| Full Idea: Proper names pose a problem for the "use" theorist. Try stating a rule of use for the name 'William G. Lycan'. | |
| From: William Lycan (Philosophy of Language [2000], Ch. 6) | |
| A reaction: Presumably it is normally used in connection with a particular human being, and is typically the subject of a grammatical sentence. Any piece of language could also be used to, say, attract someone's attention. |
| 7770 | Truth conditions will come out the same for sentences with 'renate' or 'cordate' [Lycan] |
| Full Idea: A Davidsonian truth theory will not be able to distinguish the meaning of a sentence containing 'renate' from that of one containing 'cordate'. | |
| From: William Lycan (Philosophy of Language [2000], Ch. 9) | |
| A reaction: One might achieve the distinction by referring to truth conditions in possible worlds, if there are possible worlds where some cordates are not renate. See Idea 7773. |
| 7773 | A sentence's truth conditions is the set of possible worlds in which the sentence is true [Lycan] |
| Full Idea: A sentence's truth conditions can be taken to be the set of possible worlds in which the sentence is true. | |
| From: William Lycan (Philosophy of Language [2000], Ch.10) | |
| A reaction: Presumably the meaning can't be complete possible worlds, so this must be a supplement to the normal truth conditions view proposed by Davidson. It particularly addresses the problem seen in Idea 7770. |
| 7774 | Possible worlds explain aspects of meaning neatly - entailment, for example, is the subset relation [Lycan] |
| Full Idea: The possible worlds construal affords an elegant algebra of meaning by way of set theory: e.g. entailment between sentences is just the subset relation - S1 entails S2 if S2 is true in any world in which S1 is true. | |
| From: William Lycan (Philosophy of Language [2000], Ch.10) | |
| A reaction: We might want to separate the meanings of sentences from their entailments (though Brandom links them, see Idea 7765). |
| 23279 | It is important that a person can change their character, and not just be successive 'selves' [Williams,B] |
| Full Idea: I want to emphasise the basic importance of the ordinary idea of a self or person which undergoes changes of character, as opposed to dissolving a changing person into a series of 'selves'. | |
| From: Bernard Williams (Persons, Character and Morality [1976], II) | |
| A reaction: [compressed] He mentions Derek Parfit for the rival view. Williams has the Aristotelian view, that a person has an essential nature, which endures through change, and explains that change. But that needs some non-essential character traits. |
| 23280 | Kantians have an poor account of individuals, and insist on impartiality, because they ignore character [Williams,B] |
| Full Idea: The Kantians' omission of character is a condition of their ultimate insistence on the demands of impartial morality, just as it is a reason to find inadequate their account of the individual. | |
| From: Bernard Williams (Persons, Character and Morality [1976], II) | |
| A reaction: This is also why the Kantian account of virtue is inadequate, in comparison with the Aristotelian view. |
| 23278 | For utilitarians states of affairs are what have value, not matter who produced them [Williams,B] |
| Full Idea: The basic bearer of value for Utilitarianism is the state of affairs, and hence, when the relevant causal differences have been allowed for, it cannot make any further difference who produces a given state of affairs. | |
| From: Bernard Williams (Persons, Character and Morality [1976], I) | |
| A reaction: Which is morally better, that I water your bed of flowers, or that it rains? Which is morally better, that I water them from love, or because you threaten me with a whip? |