26 ideas
| 6118 | Philosophy is logical analysis, followed by synthesis [Russell] |
| Full Idea: The business of philosophy, as I conceive it, is essentially that of logical analysis, followed by logical synthesis. | |
| From: Bertrand Russell (Logical Atomism [1924], p.162) | |
| A reaction: I am uneasy about Russell's hopes for the contribution that logic could make, but I totally agree that analysis is the route to wisdom, and I take Aristotle as my role model of an analytical philosopher, rather than the modern philosophers of logic. |
| 6116 | A logical language would show up the fallacy of inferring reality from ordinary language [Russell] |
| Full Idea: We are trying to create a perfectly logical language to prevent inferences from the nature of language to the nature of the world, which are fallacious because they depend upon the logical defects of language. | |
| From: Bertrand Russell (Logical Atomism [1924], p.159) | |
| A reaction: Wittgenstein seems to have rebelled against this idea, so that one strand of his later philosophy leads to 'ordinary language' philosophy, which is exactly what Russell is criticising. Wittgenstein seems to have seen 'logical language' as an oxymoron. |
| 6117 | Philosophy should be built on science, to reduce error [Russell] |
| Full Idea: We would be wise to build our philosophy upon science, because the risk of error in philosophy is pretty sure to be greater than in science. | |
| From: Bertrand Russell (Logical Atomism [1924], p.160) | |
| A reaction: If you do very little, it reduces the 'risk of error'. I agree that philosophers should start from the facts, and be responsive to new facts, and that science is excellent at discovering facts. But I don't think cognitive science is the new epistemology. |
| 17610 | The Axiom of Choice paradoxically allows decomposing a sphere into two identical spheres [Maddy] |
| Full Idea: One feature of the Axiom of Choice that troubled many mathematicians was the so-called Banach-Tarski paradox: using the Axiom, a sphere can be decomposed into finitely many parts and those parts reassembled into two spheres the same size as the original. | |
| From: Penelope Maddy (Defending the Axioms [2011], 1.3) | |
| A reaction: (The key is that the parts are non-measurable). To an outsider it is puzzling that the Axiom has been universally accepted, even though it produces such a result. Someone can explain that, I'm sure. |
| 6110 | Subject-predicate logic (and substance-attribute metaphysics) arise from Aryan languages [Russell] |
| Full Idea: It is doubtful whether the subject-predicate logic, with the substance-attribute metaphysic, would have been invented by people speaking a non-Aryan language. | |
| From: Bertrand Russell (Logical Atomism [1924], p.151) | |
| A reaction: This is not far off the Sapir-Whorf Hypothesis (e.g. Idea 3917), which Russell would never accept. I presume that Russell would see true logic as running deeper, and the 'Aryan' approach as just one possible way to describe it. |
| 6107 | It is logic, not metaphysics, that is fundamental to philosophy [Russell] |
| Full Idea: I hold that logic is what is fundamental in philosophy, and that schools should be characterised rather by their logic than by their metaphysics. | |
| From: Bertrand Russell (Logical Atomism [1924], p.143) | |
| A reaction: Personally I disagree. Russell seems to have been most interested in the logical form underlying language, but that seems to be because he was interested in the ontological implications of what we say, which is metaphysics. |
| 17620 | Critics of if-thenism say that not all starting points, even consistent ones, are worth studying [Maddy] |
| Full Idea: If-thenism denies that mathematics is in the business of discovering truths about abstracta. ...[their opponents] obviously don't regard any starting point, even a consistent one, as equally worthy of investigation. | |
| From: Penelope Maddy (Defending the Axioms [2011], 3.3) | |
| A reaction: I have some sympathy with if-thenism, in that you can obviously study the implications of any 'if' you like, but deep down I agree with the critics. |
| 6115 | Vagueness, and simples being beyond experience, are obstacles to a logical language [Russell] |
| Full Idea: The fact that we do not experience simples is one obstacle to the actual creation of a correct logical language, and vagueness is another. | |
| From: Bertrand Russell (Logical Atomism [1924], p.159) | |
| A reaction: The dream of creating a perfect logical language looks doomed from the start, but it is a very interesting project to try to pinpoint why it is unlikely to be possible. I say a perfect language cuts nature exactly at the joints, so find the joints. |
| 6109 | Some axioms may only become accepted when they lead to obvious conclusions [Russell] |
| Full Idea: Some of the premisses (of my logicist theory) are much less obvious than some of their consequences, and are believed chiefly because of their consequences. This will be found to be always the case when a science is arranged as a deductive system. | |
| From: Bertrand Russell (Logical Atomism [1924], p.145) | |
| A reaction: We shouldn't assume the model of self-evident axioms leading to surprising conclusions, which is something like the standard model for rationalist foundationalists. Russell nicely points out that the situation could be just the opposite |
| 17605 | Hilbert's geometry and Dedekind's real numbers were role models for axiomatization [Maddy] |
| Full Idea: At the end of the nineteenth century there was a renewed emphasis on rigor, the central tool of which was axiomatization, along the lines of Hilbert's axioms for geometry and Dedekind's axioms for real numbers. | |
| From: Penelope Maddy (Defending the Axioms [2011], 1.3) |
| 17625 | If two mathematical themes coincide, that suggest a single deep truth [Maddy] |
| Full Idea: The fact that two apparently fruitful mathematical themes turn out to coincide makes it all the more likely that they're tracking a genuine strain of mathematical depth. | |
| From: Penelope Maddy (Defending the Axioms [2011], 5.3ii) |
| 17615 | Every infinite set of reals is either countable or of the same size as the full set of reals [Maddy] |
| Full Idea: One form of the Continuum Hypothesis is the claim that every infinite set of reals is either countable or of the same size as the full set of reals. | |
| From: Penelope Maddy (Defending the Axioms [2011], 2.4 n40) |
| 17618 | Set-theory tracks the contours of mathematical depth and fruitfulness [Maddy] |
| Full Idea: Our set-theoretic methods track the underlying contours of mathematical depth. ...What sets are, most fundamentally, is markers for these contours ...they are maximally effective trackers of certain trains of mathematical fruitfulness. | |
| From: Penelope Maddy (Defending the Axioms [2011], 3.4) | |
| A reaction: This seems to make it more like a map of mathematics than the actual essence of mathematics. |
| 17614 | The connection of arithmetic to perception has been idealised away in modern infinitary mathematics [Maddy] |
| Full Idea: Ordinary perceptual cognition is most likely involved in our grasp of elementary arithmetic, but ...this connection to the physical world has long since been idealized away in the infinitary structures of contemporary pure mathematics. | |
| From: Penelope Maddy (Defending the Axioms [2011], 2.3) | |
| A reaction: Despite this, Maddy's quest is for a 'naturalistic' account of mathematics. She ends up defending 'objectivity' (and invoking Tyler Burge), rather than even modest realism. You can't 'idealise away' the counting of objects. I blame Cantor. |
| 6108 | Maths can be deduced from logical axioms and the logic of relations [Russell] |
| Full Idea: I think that no one will dispute that from certain ideas and axioms of formal logic, but with the help of the logic of relations, all pure mathematics can be deduced. | |
| From: Bertrand Russell (Logical Atomism [1924], p.145) | |
| A reaction: It has been said for a long time that Gödel's Incompleteness Theorems of 1930 disproved this claim, though recently there have been defenders of logicism. Beginning with 'certain ideas' sounds like begging the question. |
| 10968 | Russell gave up logical atomism because of negative, general and belief propositions [Russell, by Read] |
| Full Idea: Russell preceded Wittgenstein in deciding that the reduction of all propositions to atomic propositions could not be achieved. The problem cases were negative propositions, general propositions, and belief propositions. | |
| From: report of Bertrand Russell (Logical Atomism [1924]) by Stephen Read - Thinking About Logic Ch.1 |
| 6113 | To mean facts we assert them; to mean simples we name them [Russell] |
| Full Idea: The way to mean a fact is to assert it; the way to mean a simple is to name it. | |
| From: Bertrand Russell (Logical Atomism [1924], p.156) | |
| A reaction: Thus logical atomism is a linguistic programme, of reducing our language to a foundation of pure names. The recent thought of McDowell and others is aimed at undermining any possibility of a 'simple' in perception. The myth of 'The Given'. |
| 6114 | 'Simples' are not experienced, but are inferred at the limits of analysis [Russell] |
| Full Idea: When I speak of 'simples' I am speaking of something not experienced as such, but known only inferentially as the limits of analysis. | |
| From: Bertrand Russell (Logical Atomism [1924], p.158) | |
| A reaction: He claims that the simples are 'known', so he does not mean purely theoretical entities. They have something like the status of quarks in physics, whose existence is inferred from experience. |
| 21722 | Better to construct from what is known, than to infer what is unknown [Russell] |
| Full Idea: Whenever possible, substitute constructions out of known entities for inferences to unknown entities. | |
| From: Bertrand Russell (Logical Atomism [1924], p.161), quoted by Bernard Linsky - Russell's Metaphysical Logic 7 | |
| A reaction: In 1919 he said that the alternative, of 'postulating' new entities, has 'all the advantages of theft over honest toil' [IMP p.71]. This is Russell's commitment to 'constructing' everything, even his concept of matter. Arithmetic as PA is postulation. |
| 6111 | As propositions can be put in subject-predicate form, we wrongly infer that facts have substance-quality form [Russell] |
| Full Idea: Since any proposition can be put into a form with a subject and a predicate, united by a copula, it is natural to infer that every fact consists in the possession of a quality by a substance, which seems to me a mistake. | |
| From: Bertrand Russell (Logical Atomism [1924], p.152) | |
| A reaction: This disagrees with McGinn on facts (Idea 6075). I approve of this warning from Russell, which is a recognition that we can't just infer our metaphysics from our language. I think of this as the 'Frege Fallacy', which ensnared Quine and others. |
| 12899 | The timid student has knowledge without belief, lacking confidence in their correct answer [Lewis] |
| Full Idea: I allow knowledge without belief, as in the case of the timid student who knows the answer but has no confidence that he has it right, and so does not believe what he knows. | |
| From: David Lewis (Elusive Knowledge [1996], p.429) | |
| A reaction: [He cites Woozley 1953 for the timid student] I don't accept this example (since my views on knowledge are rather traditional, I find). Why would the student give that answer if they didn't believe it? Sustained timid correctness never happens. |
| 12897 | To say S knows P, but cannot eliminate not-P, sounds like a contradiction [Lewis] |
| Full Idea: If you claim that S knows that P, and yet grant that S cannot eliminate a certain possibility of not-P, it certainly seems as if you have granted that S does not after all know that P. To speak of fallible knowledge just sounds contradictory. | |
| From: David Lewis (Elusive Knowledge [1996], p.419) | |
| A reaction: Starting from this point, fallibilism seems to be a rather bold move. The only sensible response seems to be to relax the requirement that not-P must be eliminable. Best: in one epistemic context P, in another not-P. |
| 12898 | Justification is neither sufficient nor necessary for knowledge [Lewis] |
| Full Idea: I don't agree that the mark of knowledge is justification, first because justification isn't sufficient - your true opinion that you will lose the lottery isn't knowledge, whatever the odds; and also not necessary - for what supports perception or memory? | |
| From: David Lewis (Elusive Knowledge [1996]) | |
| A reaction: I don't think I agree. The point about the lottery is that an overwhelming reason will never get you to knowing that you won't win. But good reasons are coherent, not statistical. If perceptions are dubious, justification must be available. |
| 12895 | Knowing is context-sensitive because the domain of quantification varies [Lewis, by Cohen,S] |
| Full Idea: The context-sensitivity of 'knows' is a function of contextual restrictions on the domain of quantification. | |
| From: report of David Lewis (Elusive Knowledge [1996]) by Stewart Cohen - Contextualism Defended p.68 | |
| A reaction: I think the shifting 'domain of quantification' is one of the most interesting features of ordinary talk. Or, more plainly. 'what are you actually talking about?' is the key question in any fruitful dialogue. Sophisticated speakers tacitly shift domain. |
| 19562 | We have knowledge if alternatives are eliminated, but appropriate alternatives depend on context [Lewis, by Cohen,S] |
| Full Idea: S knows P if S's evidence eliminates every alternative. But the nature of the alternatives depends on context. So for Lewis, the context sensitivity of 'knows' is a function of contextual restrictions ln the domain of quantification. | |
| From: report of David Lewis (Elusive Knowledge [1996]) by Stewart Cohen - Contextualism Defended (and reply) 1 | |
| A reaction: A typical modern attempt to 'regiment' a loose term like 'context'. That said, I like the idea. I'm struck by how the domain varies during a conversation (as in 'what we are talking about'). Domains standardly contain 'objects', though. |
| 6112 | Meaning takes many different forms, depending on different logical types [Russell] |
| Full Idea: There is not one relation of meaning between words and what they stand for, but as many relations of meaning, each of a different logical type, as there are logical types among the objects for which there are words. | |
| From: Bertrand Russell (Logical Atomism [1924], p.153) | |
| A reaction: This might be a good warning for those engaged in the externalist/internalist debate over the meaning of concepts such as natural kind terms like 'water'. I could have an external meaning for 'elms', but an internal meaning for 'ferns'. |