42 ideas
| 9023 | If you say that a contradiction is true, you change the meaning of 'not', and so change the subject [Quine] |
| 19389 | Truth is a characteristic of possible thoughts [Leibniz] |
| 19388 | True and false seem to pertain to thoughts, yet unthought propositions seem to be true or false [Leibniz] |
| 16477 | Asserting not-p is saying p is false [Russell] |
| 9012 | Talk of 'truth' when sentences are mentioned; it reminds us that reality is the point of sentences [Quine] |
| 9011 | Truth is redundant for single sentences; we do better to simply speak the sentence [Quine] |
| 9013 | We can eliminate 'or' from our basic theory, by paraphrasing 'p or q' as 'not(not-p and not-q)' [Quine] |
| 16484 | There are four experiences that lead us to talk of 'some' things [Russell] |
| 9020 | My logical grammar has sentences by predication, then negation, conjunction, and existential quantification [Quine] |
| 9028 | Maybe logical truth reflects reality, but in different ways in different languages [Quine] |
| 16486 | The physical world doesn't need logic, but the mental world does [Russell] |
| 10014 | Quine rejects second-order logic, saying that predicates refer to multiple objects [Quine, by Hodes] |
| 10828 | Quantifying over predicates is treating them as names of entities [Quine] |
| 2947 | Questions wouldn't lead anywhere without the law of excluded middle [Russell] |
| 9024 | Excluded middle has three different definitions [Quine] |
| 10012 | Quantification theory can still be proved complete if we add identity [Quine] |
| 16480 | A disjunction expresses indecision [Russell] |
| 16479 | 'Or' expresses hesitation, in a dog at a crossroads, or birds risking grabbing crumbs [Russell] |
| 16481 | 'Or' expresses a mental state, not something about the world [Russell] |
| 16487 | Maybe the 'or' used to describe mental states is not the 'or' of logic [Russell] |
| 16483 | Disjunction may also arise in practice if there is imperfect memory. [Russell] |
| 9016 | Names are not essential, because naming can be turned into predication [Quine] |
| 9015 | Universal quantification is widespread, but it is definable in terms of existential quantification [Quine] |
| 9025 | You can't base quantification on substituting names for variables, if the irrationals cannot all be named [Quine] |
| 9026 | Some quantifications could be false substitutionally and true objectually, because of nameless objects [Quine] |
| 10705 | Putting a predicate letter in a quantifier is to make it the name of an entity [Quine] |
| 9027 | A sentence is logically true if all sentences with that grammatical structure are true [Quine] |
| 16475 | A 'heterological' predicate can't be predicated of itself; so is 'heterological' heterological? Yes=no! [Russell] |
| 9017 | Predicates are not names; predicates are the other parties to predication [Quine] |
| 9018 | A physical object is the four-dimensional material content of a portion of space-time [Quine] |
| 9019 | Four-d objects helps predication of what no longer exists, and quantification over items from different times [Quine] |
| 9014 | Some conditionals can be explained just by negation and conjunction: not(p and not-q) [Quine] |
| 16482 | All our knowledge (if verbal) is general, because all sentences contain general words [Russell] |
| 4758 | Naïve realism leads to physics, but physics then shows that naïve realism is false [Russell] |
| 16476 | For simple words, a single experience can show that they are true [Russell] |
| 16485 | Perception can't prove universal generalisations, so abandon them, or abandon empiricism? [Russell] |
| 9009 | Single words are strongly synonymous if their interchange preserves truth [Quine] |
| 9007 | It makes no sense to say that two sentences express the same proposition [Quine] |
| 9008 | There is no rule for separating the information from other features of sentences [Quine] |
| 9010 | We can abandon propositions, and just talk of sentences and equivalence [Quine] |
| 9021 | A good way of explaining an expression is saying what conditions make its contexts true [Quine] |
| 16478 | A mother cat is paralysed if equidistant between two needy kittens [Russell] |