display all the ideas for this combination of philosophers
33 ideas
| 23502 | Logic fills the world, to its limits [Wittgenstein] |
| Full Idea: Logic pervades the world: the limits of the world are also its limits. | |
| From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 5.61) | |
| A reaction: This is a gospel belief for hardcore analytic philosophy. Hence Williamson writes a book on modal logic as metaphysics. |
| 18724 | In logic nothing is hidden [Wittgenstein] |
| Full Idea: In logic nothing is hidden. | |
| From: Ludwig Wittgenstein (Lectures 1930-32 (student notes) [1931], B XII.3) | |
| A reaction: If so, then the essence of logic must be there for all to see. The rules of natural deduction are a good shot at showing this. |
| 16908 | We can dispense with self-evidence, if language itself prevents logical mistakes [Jeshion on Wittgenstein] |
| Full Idea: The 'self-evidence' of which Russell talks so much can only be dispensed with in logic if language itself prevents any logical mistake. | |
| From: comment on Ludwig Wittgenstein (Notebooks 1914-1916 [1915], 4) by Robin Jeshion - Frege's Notion of Self-Evidence 4 | |
| A reaction: Jeshion presents this as a key idea, turning against Frege, and is the real source of the 'linguistic turn' in philosophy. If self-evidence is abandoned, then language itself is the guide to truth, so study language. I think I prefer Frege. See Quine? |
| 23504 | Logic concerns everything that is subject to law; the rest is accident [Wittgenstein] |
| Full Idea: The exploration of logic means the exploration of everything that is subject to law. And outside logic everything is accidental. | |
| From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 6.3) | |
| A reaction: Why should laws be logical? Legislatures can pass whimsical laws. Does he mean that the laws of nature are logically necessary? He can't just mean logical laws. |
| 6428 | Wittgenstein is right that logic is just tautologies [Wittgenstein, by Russell] |
| Full Idea: I think Wittgenstein is right when he says (in the 'Tractatus') that logic consists wholly of tautologies. | |
| From: report of Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921]) by Bertrand Russell - My Philosophical Development Ch.10 | |
| A reaction: Despite Russell's support, I find this hard to accept. While a 'pure' or 'Platonist' logic may be hard to demonstrate or believe, I have a strong gut feeling that logic is more of a natural phenomenon than a human convention. |
| 11062 | Logic is a priori because it is impossible to think illogically [Wittgenstein] |
| Full Idea: What makes logic a priori is the impossibility of illogical thought. | |
| From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 5.4731) | |
| A reaction: That places the a priori aspect of it in us (in the epistemology), rather than in the necessity of the logic (the ontology), which is as Kripke says it should be. |
| 18277 | If q implies p, that is justified by q and p, not by some 'laws' of inference [Wittgenstein] |
| Full Idea: If p follows from q, I can make an inference from q to p, deduce p from q. The nature of the inference can be gathered only from the two propositions. They are the only possible justification of the inference. 'Laws of Inference' would be superfluous. | |
| From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 5.132) | |
| A reaction: That seems to imply that each inference is judged on its particulars. But logic aims to be general. There seem to be 'laws' at a more complex level in the logic. |
| 18162 | The propositions of logic are analytic tautologies [Wittgenstein] |
| Full Idea: The propositions of logic are tautologies. Therefore the propositions of logic say nothing. (They are the analytic propositions). | |
| From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 6.1) |
| 7537 | Wittgenstein convinced Russell that logic is tautologies, not Platonic forms [Wittgenstein, by Monk] |
| Full Idea: Russell took a Platonist view of logic, but reading the 'Tractatus' convinced him that logic was purely linguistic, so-called 'logical truths' being nothing more than tautologies. | |
| From: report of Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921]) by Ray Monk - Bertrand Russell: Spirit of Solitude Ch.1 | |
| A reaction: If p-and-q and p-or-q are both tautologies, how do you explain the difference between them? The first is an indicative proposition about the actual world, but the second is modal. They are asserting very different things. |
| 18709 | Laws of logic are like laws of chess - if you change them, it's just a different game [Wittgenstein] |
| Full Idea: I might as well question the laws of logic as the laws of chess. If I change the rules it is a different game and there is an end of it. | |
| From: Ludwig Wittgenstein (Lectures 1930-32 (student notes) [1931], A XI.3) | |
| A reaction: No, that isn't the end of it, because there are meta-criteria for preferring one game to another. Why don't we just give up classical logic? It would be such fun to have a wild wacky logic. We can start with 'tonk'. |
| 23496 | Two colours in the same place is ruled out by the logical structure of colour [Wittgenstein] |
| Full Idea: The simultaneous presence of two colours in the same place in the visual field is impossible, in fact logically impossible, since it is ruled out by the logical structure of colour. | |
| From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 6.3751) | |
| A reaction: This sounds the wrong way around. We derive our concept of the logic of colour from experiencing the total incompatibility of two colours in the same location. What if each of our eyes saw a different colour? |
| 18736 | Contradiction is between two rules, not between rule and reality [Wittgenstein] |
| Full Idea: Contradiction is between one rule and another, not between rule and reality. | |
| From: Ludwig Wittgenstein (Lectures 1930-32 (student notes) [1931], C XIII) | |
| A reaction: If I say 'he is sitting' and 'he is standing', it seems to be reality which produces the contradiction. What 'rule' could possibly do it? The rule which says sitting and standing are incompatible? But what makes that so? |
| 18154 | The sign of identity is not allowed in 'Tractatus' [Wittgenstein, by Bostock] |
| Full Idea: The 'Tractatus' does not allow the introduction of a sign for identity. | |
| From: report of Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921]) by David Bostock - Philosophy of Mathematics 9.B.4 |
| 13429 | The identity sign is not essential in logical notation, if every sign has a different meaning [Wittgenstein, by Ramsey] |
| Full Idea: Wittgenstein discovered that the sign of identity is not a necessary constituent of logical notation, but can be replaced by the convention that different signs must have different meanings. | |
| From: report of Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921]) by Frank P. Ramsey - The Foundations of Mathematics p.139 | |
| A reaction: [Ramsey cites p.139 - need to track down the modern reference] Hence in modern logic it is usually necessary to say that we are using 'classical logic with identity', since the use of identity is very convenient, and reasonably harmless (I think). |
| 18276 | A statement's logical form derives entirely from its constituents [Wittgenstein] |
| Full Idea: The logical form of the statement must already be given in the forms of its constituents. | |
| From: Ludwig Wittgenstein (Notebooks 1914-1916 [1915], 23e) | |
| A reaction: This would evidently require each constituent to have a 'logical form'. It is hard to see what that could beyond its part of speech. Do two common nouns have the same logical form? |
| 18743 | Wittgenstein says we want the grammar of problems, not their first-order logical structure [Wittgenstein, by Horsten/Pettigrew] |
| Full Idea: For the later Wittgenstein what we should be after is the grammatical structure of philosophical problems, not the first-order logical structure of such problems. | |
| From: report of Ludwig Wittgenstein (Philosophical Investigations [1952]) by Horsten,L/Pettigrew,R - Mathematical Methods in Philosophy 2 | |
| A reaction: This is the most sympathetic spin I have ever seen put on the apparent rather anti-philosophical later Wittgenstein. I nurse doubts about highly formal approaches to philosophy, and maybe 'grammar' (whatever that is) is our target. |
| 18268 | Apparent logical form may not be real logical form [Wittgenstein] |
| Full Idea: The apparent logical form of the proposition need not be its real logical form. | |
| From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 4.0031), quoted by J. Alberto Coffa - The Semantic Tradition from Kant to Carnap 6 'The incom' | |
| A reaction: This is one of the key doctrines of modern analytic philosophy. |
| 10905 | My fundamental idea is that the 'logical constants' do not represent [Wittgenstein] |
| Full Idea: My fundamental idea is that the 'logical constants' do not represent; that the logic of facts does not allow of representation. | |
| From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 4.0312) | |
| A reaction: This seems to a firm rebuttal of any sort of platonism about logic, and implies a purely formal account. |
| 6563 | 'And' and 'not' are non-referring terms, which do not represent anything [Wittgenstein, by Fogelin] |
| Full Idea: Wittgenstein's 'fundamental idea' is that the 'and' and 'not' which guarantee the truth of "not p and not-p" are meaningful, but do not get their meaning by representing or standing for or referring to some kind of entity; they are non-referring terms. | |
| From: report of Ludwig Wittgenstein (Notebooks 1914-1916 [1915], §37) by Robert Fogelin - Walking the Tightrope of Reason Ch.1 | |
| A reaction: Wittgenstein then defines the terms using truth tables, to show what they do, rather than what they stand for. This seems to me to be a candidate for the single most important idea in the history of the philosophy of logic. |
| 23493 | 'Not' isn't an object, because not-not-p would then differ from p [Wittgenstein] |
| Full Idea: If there were an object called 'not', it would follow that 'not-not-p' would say something different from what 'p' said, just because the one proposition would then be about 'not', and the other would not. | |
| From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 5.44) | |
| A reaction: That is, the first proposition would be about not-p, and the second would be about p. Assuming we can say what such things are 'about'. A rather good argument that the connectives are not entities. P and double-negated P should be indistinguishable. |
| 18723 | We may correctly use 'not' without making the rule explicit [Wittgenstein] |
| Full Idea: Correct use does not imply the ability to make the rules explicit. Understanding 'not' is like understanding a move in chess. | |
| From: Ludwig Wittgenstein (Lectures 1930-32 (student notes) [1931], B XII.1) |
| 18718 | Saying 'and' has meaning is just saying it works in a sentence [Wittgenstein] |
| Full Idea: When we say that the word 'and' has meaning what we mean is that it works in a sentence and is not just a flourish. | |
| From: Ludwig Wittgenstein (Lectures 1930-32 (student notes) [1931], B VIII.2) |
| 7784 | 'Object' is a pseudo-concept, properly indicated in logic by the variable x [Wittgenstein] |
| Full Idea: The variable name ‘x’ is the proper sign of the pseudo-concept object. Wherever the word ‘object’ (‘thing’, ‘entity’, etc.) is rightly used, it is expressed in logical symbolism by the variable name. | |
| From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 4.1272) | |
| A reaction: This seems to be the germ of Quine's famous dictum (Idea 1610). I am not persuaded that because logic must handle an object as a variable, that it follows that we are dealing with a pseudo-concept. Let logic limp behind life. |
| 23506 | Names are primitive, and cannot be analysed [Wittgenstein] |
| Full Idea: A name cannot be dissected any further by means of a definition: it is a primitive sign. | |
| From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 3.26) | |
| A reaction: All logicians and analytic philosophers seem to agree on this. He means terms which pick out specific objects. |
| 18727 | A person's name doesn't mean their body; bodies don't sit down, and their existence can be denied [Wittgenstein] |
| Full Idea: The meaning of the words 'Professor Moore' is not a certain human body, because we do not say that the meaning sits on the sofa, and the words occur in the proposition 'Professor Moore does not exist'. | |
| From: Ludwig Wittgenstein (Lectures 1930-32 (student notes) [1931], B Easter) | |
| A reaction: Brilliant. Love it. Kripke ending up denying the existence of 'meanings'. |
| 4139 | Naming is a preparation for description [Wittgenstein] |
| Full Idea: Naming is a preparation for description. | |
| From: Ludwig Wittgenstein (Philosophical Investigations [1952], §049) | |
| A reaction: Something has to be the starting point for a description. And yet a description could turn out to be an elaborate name. |
| 4946 | A name is not determined by a description, but by a cluster or family [Wittgenstein, by Kripke] |
| Full Idea: According to Wittgenstein (and Searle) the referent of a name is determined not by a single description but by some cluster or family. | |
| From: report of Ludwig Wittgenstein (Philosophical Investigations [1952], §079) by Saul A. Kripke - Naming and Necessity lectures Lecture 1 | |
| A reaction: It is because of this characteristically woolly, indeterminate and relativist view of Wittgenstein that I (and most people) find Kripke's notion of a 'baptism' so refreshing. It cuts throught the fog of language, and connects to reality. |
| 7089 | A name is primitive, and its meaning is the object [Wittgenstein] |
| Full Idea: A name means an object; an object is its meaning. ...A name cannot be dissected further by means of a definition: it is a primitive sign. | |
| From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 3.203/3.26) | |
| A reaction: This is the optimistic view of names, that they are the point at which language plugs into the world (Russell preferred demonstratives for that job). Kripke's baptismal view of names has the same aspiration. |
| 9467 | Wittgenstein tried unsuccessfully to reduce quantifiers to conjunctions and disjunctions [Wittgenstein, by Jacquette] |
| Full Idea: Wittgenstein reduces the universal quantifier to conjunctions of singular predications, and the existential quantifier to disjunctions of singular predications. ..This is nowadays understood as a failed effort. | |
| From: report of Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921]) by Dale Jacquette - Intro to III: Quantifiers p.143 | |
| A reaction: The problem this meets has something to do with infinite objects. In a domain of three objects it looks like a perfectly plausible strategy. 'All' is all three, and 'Some' is at least one of the three. |
| 15089 | Logical proof just explicates complicated tautologies [Wittgenstein] |
| Full Idea: Proof in logic is merely a mechanical expedient to facilitate recognition of tautologies in complicated cases. | |
| From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 6.1262) |
| 13830 | Logical truths are just 'by-products' of the introduction rules for logical constants [Wittgenstein, by Hacking] |
| Full Idea: Wittgenstein's by-product theory is that the meanings of the logical constants are conveyed by their introduction rules, and these rules have as a by-product the class of logical truths. | |
| From: report of Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921]) by Ian Hacking - What is Logic? §03 | |
| A reaction: I find this approach highly plausible. All the truths about chess openings are just a by-product of the original rules. |
| 19292 | Logic doesn't split into primitive and derived propositions; they all have the same status [Wittgenstein] |
| Full Idea: All the propositions of logic are of equal status: it is not the case that some of them are essentially primitive propositions and others essentially derived propositions. | |
| From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 6.127) | |
| A reaction: So axioms are conventional. This specifically contradicts the claims of Frege and the earlier Russell. Their view is that logic has an explanatory essence, found in some core axioms or rules or concepts. I agree with them. |
| 6569 | 'This sentence is false' sends us in a looping search for its proposition [Wittgenstein, by Fogelin] |
| Full Idea: According to Wittgenstein, 'this sentence is false' sends us off on an endless, looping search for the proposition to be evaluated. | |
| From: report of Ludwig Wittgenstein (Zettel [1950], §691) by Robert Fogelin - Walking the Tightrope of Reason Ch.2 | |
| A reaction: Fogelin quotes this as one possible strategy for dealing with the Liar Paradox. It doesn't sound like much of a solution to the paradox, merely an account of why it is so annoying. Wittgenstein's challenge is that the Cretan can't state his problem. |