40 ideas
9023 | If you say that a contradiction is true, you change the meaning of 'not', and so change the subject [Quine] |
21544 | It seems that when a proposition is false, something must fail to subsist [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] |
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] |
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] |
21539 | Excluded middle can be stated psychologically, as denial of p implies assertion of not-p [Russell] |
9024 | Excluded middle has three different definitions [Quine] |
10012 | Quantification theory can still be proved complete if we add identity [Quine] |
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] |
21538 | If two people perceive the same object, the object of perception can't be in the mind [Russell] |
21534 | The only thing we can say about relations is that they relate [Russell] |
21540 | Relational propositions seem to be 'about' their terms, rather than about the relation [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] |
21536 | When I perceive a melody, I do not perceive the notes as existing [Russell] |
21535 | Objects only exist if they 'occupy' space and time [Russell] |
9019 | Four-d objects helps predication of what no longer exists, and quantification over items from different times [Quine] |
21533 | Contingency arises from tensed verbs changing the propositions to which they refer [Russell] |
9014 | Some conditionals can be explained just by negation and conjunction: not(p and not-q) [Quine] |
21537 | I assume we perceive the actual objects, and not their 'presentations' [Russell] |
21532 | Full empiricism is not tenable, but empirical investigation is always essential [Russell] |
21542 | Do incorrect judgements have non-existent, or mental, or external objects? [Russell] |
21541 | The complexity of the content correlates with the complexity of the object [Russell] |
9009 | Single words are strongly synonymous if their interchange preserves truth [Quine] |
21543 | If p is false, then believing not-p is knowing a truth, so negative propositions must exist [Russell] |
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] |
13304 | Learned men gain more in one day than others do in a lifetime [Posidonius] |
20820 | Time is an interval of motion, or the measure of speed [Posidonius, by Stobaeus] |