15 ideas
| 23367 | Even pointing a finger should only be done for a reason [Epictetus] |
| Full Idea: Philosophy says it is not right even to stretch out a finger without some reason. | |
| From: Epictetus (fragments/reports [c.57], 15) | |
| A reaction: The key point here is that philosophy concerns action, an idea on which Epictetus is very keen. He rather despise theory. This idea perfectly sums up the concept of the wholly rational life (which no rational person would actually want to live!). |
| 22438 | Philosophy is largely concerned with finding the minimum that science could get by with [Quine] |
| Full Idea: Philosophy is in large part concerned with ...what science could get along with, could be reconstructed by means of, as distinct from what science has historically made us of. | |
| From: Willard Quine (Mr Strawson on Logical Theory [1953], V) | |
| A reaction: This nicely summarises the programme for the whole of the philosophy of David Lewis, who was Quine's pupil. If you start by asking what it could 'get by with', it is not surprising that simplicity is the top intellectual virtue for both of them. |
| 22436 | Logicians don't paraphrase logic into language, because they think in the symbolic language [Quine] |
| Full Idea: The logician does not even need to paraphrase the vernacular into his logical notation, for he has learned to think directly in his logical notation, or even (which is the beauty of the thing) to let it think for him. | |
| From: Willard Quine (Mr Strawson on Logical Theory [1953], V) | |
| A reaction: See Williamson's love of logic (and his book on modal metaphysics). This idea embodies the dream of hardcore Frege-Russellian analytic philosophers. I wish someone had told me when I studied logic that the target was to actually think symbolically. |
| 22431 | Good algorithms and theories need many occurrences of just a few elements [Quine] |
| Full Idea: The power and simplicity of an algorithm, or indeed of any theory, depend on there being many occurrences of few elements rather than few occurrences of many. | |
| From: Willard Quine (Mr Strawson on Logical Theory [1953], III) | |
| A reaction: Not sure how this applies to a software function. One which produces a good result from a large number of input variables sounds particularly impressive to me. Many occurrences of a single variable sounds rather inefficient. |
| 22435 | The logician's '→' does not mean the English if-then [Quine] |
| Full Idea: The logician drops 'if-then' in favour of '→' without ever entertaining the mistaken idea that they are synonymous. | |
| From: Willard Quine (Mr Strawson on Logical Theory [1953], V) | |
| A reaction: [Quine uses the older horseshoe symbol] The conditional in English is not well understood, whereas the symbol is unambiguous. A warning to myself, since I have a tendency to translate symbols into English all the time. [p.156 'implies' is worse!] |
| 22433 | It is important that the quantification over temporal entities is timeless [Quine] |
| Full Idea: It would be hard to exaggerate the importance of recognising the timelessness of quantification over temporal entities. | |
| From: Willard Quine (Mr Strawson on Logical Theory [1953], IV) | |
| A reaction: 'Some moments in this cricket match were crucial'. The domain is not timeless, but consists of moments in this match. Can you say the quantifier is timeless but its domain is not? Only in the sense that 'very' is a timeless word, I think. |
| 10196 | The Axiom of Choice needs a criterion of choice [Black] |
| Full Idea: Some mathematicians seem to think that talk of an Axiom of Choice allows them to choose a single member of a collection when there is no criterion of choice. | |
| From: Max Black (The Identity of Indiscernibles [1952], p.68) |
| 22437 | Logical languages are rooted in ordinary language, and that connection must be kept [Quine] |
| Full Idea: A logical language is not independent of ordinary language. It has its roots in ordinary language, and these roots are not to be severed. | |
| From: Willard Quine (Mr Strawson on Logical Theory [1953], V) | |
| A reaction: Music to my ears. When you study logic, no one has to teach you what the words 'or' and 'if-then' mean, but they are disambiguated by the symbolism. The roots of logic are in ordinary talk of 'and', 'or' and 'not', which is the real world. |
| 22434 | Reduction to logical forms first simplifies idioms and grammar, then finds a single reading of it [Quine] |
| Full Idea: Ordinary language is reduced to logical form in two ways: reduction of the variety of idioms and grammatical constructions, and reduction of each surviving idiom to one fixed and convenient interpretation. | |
| From: Willard Quine (Mr Strawson on Logical Theory [1953], V) | |
| A reaction: Is there a conflict between a 'fixed' and a 'convenient' result? By 'fixed' I suppose he means it is a commitment (to not waver). What is the logical form of a sentence which is deliberately ambiguous? |
| 10194 | Two things can only be distinguished by a distinct property or a distinct relation [Black] |
| Full Idea: The only way we can discover that two things exist is by finding out that one has a quality not possessed by the other, or else that one has a relational characteristic that the other hasn't. | |
| From: Max Black (The Identity of Indiscernibles [1952], p.67) | |
| A reaction: At least this doesn't conflate relations with properties. Note that this idea is clearly epistemological, and in no way rules out the separateness of two objects which none of us can ever discern. Maybe the Earth has two Suns, which imperceptibly swap. |
| 10193 | The 'property' of self-identity is uselessly tautological [Black] |
| Full Idea: Saying that 'a has the property of being identical with a' is a roundabout way of saying nothing - a useless tautology - and means not more than 'a is a' | |
| From: Max Black (The Identity of Indiscernibles [1952], p.66) | |
| A reaction: This matter resembles the problem of the number zero, and the empty set, which seem to be crucial entities for logicians, but of no interest to a common sense view of the world. So much the worse for logic, I am inclined to say. |
| 10195 | If the universe just held two indiscernibles spheres, that refutes the Identity of Indiscernibles [Black] |
| Full Idea: Isn't it logically possible that the universe should have contained nothing but two exactly similar spheres? ...So two things would have all their properties in common, and this would refute the Principle of the Identity of Indiscernibles. | |
| From: Max Black (The Identity of Indiscernibles [1952], p.67) | |
| A reaction: [Black is the originator of this famous example] It also appears to be naturally possible. An observer at an instant of viewing will discern a relational difference relative to themselves. Most people take Black's objection to be decisive. |
| 22432 | Normally conditionals have no truth value; it is the consequent which has a conditional truth value [Quine] |
| Full Idea: Ordinarily the conditional is not thought of as true or false at all, but rather the consequent is thought of as conditionally true or false given the antecedent. | |
| From: Willard Quine (Mr Strawson on Logical Theory [1953], III) | |
| A reaction: At first this seems obvious, but a conditional asserts a relationship between two propositions, and so presumably it is true if that relationship exists. 'Is it actually true that if it is Monday then everyone in the office is depressed?'. |
| 22430 | If we understand a statement, we know the circumstances of its truth [Quine] |
| Full Idea: We understand under what circumstances to say of any given statement that it is true, just as clearly as we understand the statement itself. | |
| From: Willard Quine (Mr Strawson on Logical Theory [1953], II) | |
| A reaction: This probably shouldn't be taken as a theory of meaning (in which Quine doesn't really believe) but as a plausible statement of correlated facts. Hypothetical assertions might be a problem case. 'If only I could be in two places at once'? |
| 13713 | Quine holds time to be 'space-like': past objects are as real as spatially remote ones [Quine, by Sider] |
| Full Idea: Quine's view is that time is 'space-like'. Past objects are as real as present ones; they're just temporally distant, just as spatially distant objects are just as real as the ones around here. | |
| From: report of Willard Quine (Mr Strawson on Logical Theory [1953]) by Theodore Sider - Logic for Philosophy 7.3.1 | |
| A reaction: Something is a wrong with a view that says that a long-dead person is just as real as one currently living. Death is rather more than travelling to a distant place. Arthur Prior responded to Quine by saying 'tense operators' are inescapable. |