66 ideas
22270 | Frege changed philosophy by extending logic's ability to check the grounds of thinking [Potter on Frege] |
8939 | We should not describe human laws of thought, but how to correctly track truth [Frege, by Fisher] |
21616 | Truth and falsity apply to suppositions as well as to assertions [Williamson] |
21623 | True and false are not symmetrical; false is more complex, involving negation [Williamson] |
4971 | I don't use 'subject' and 'predicate' in my way of representing a judgement [Frege] |
17745 | For Frege, 'All A's are B's' means that the concept A implies the concept B [Frege, by Walicki] |
21602 | Many-valued logics don't solve vagueness; its presence at the meta-level is ignored [Williamson] |
7728 | Frege has a judgement stroke (vertical, asserting or judging) and a content stroke (horizontal, expressing) [Frege, by Weiner] |
16881 | The laws of logic are boundless, so we want the few whose power contains the others [Frege] |
7622 | In 1879 Frege developed second order logic [Frege, by Putnam] |
21611 | Formal semantics defines validity as truth preserved in every model [Williamson] |
21606 | 'Bivalence' is the meta-linguistic principle that 'A' in the object language is true or false [Williamson] |
21605 | Excluded Middle is 'A or not A' in the object language [Williamson] |
7729 | Frege replaced Aristotle's subject/predicate form with function/argument form [Frege, by Weiner] |
9950 | A quantifier is a second-level predicate (which explains how it contributes to truth-conditions) [Frege, by George/Velleman] |
9991 | For Frege the variable ranges over all objects [Frege, by Tait] |
10536 | Frege's domain for variables is all objects, but modern interpretations first fix the domain [Dummett on Frege] |
7730 | Frege introduced quantifiers for generality [Frege, by Weiner] |
7742 | Frege reduced most quantifiers to 'everything' combined with 'not' [Frege, by McCullogh] |
13824 | Proof theory began with Frege's definition of derivability [Frege, by Prawitz] |
13609 | Frege produced axioms for logic, though that does not now seem the natural basis for logic [Frege, by Kaplan] |
21612 | Or-elimination is 'Argument by Cases'; it shows how to derive C from 'A or B' [Williamson] |
21599 | A sorites stops when it collides with an opposite sorites [Williamson] |
17855 | It may be possible to define induction in terms of the ancestral relation [Frege, by Wright,C] |
10607 | Frege's logic has a hierarchy of object, property, property-of-property etc. [Frege, by Smith,P] |
11008 | Existence is not a first-order property, but the instantiation of a property [Frege, by Read] |
21589 | When bivalence is rejected because of vagueness, we lose classical logic [Williamson] |
21596 | Vagueness undermines the stable references needed by logic [Williamson] |
21601 | A vague term can refer to very precise elements [Williamson] |
21629 | Equally fuzzy objects can be identical, so fuzziness doesn't entail vagueness [Williamson] |
21591 | Vagueness is epistemic. Statements are true or false, but we often don't know which [Williamson] |
21619 | If a heap has a real boundary, omniscient speakers would agree where it is [Williamson] |
21620 | The epistemic view says that the essence of vagueness is ignorance [Williamson] |
21622 | If there is a true borderline of which we are ignorant, this drives a wedge between meaning and use [Williamson] |
9120 | Vagueness in a concept is its indiscriminability from other possible concepts [Williamson] |
21625 | The vagueness of 'heap' can remain even when the context is fixed [Williamson] |
21614 | The 'nihilist' view of vagueness says that 'heap' is not a legitimate concept [Williamson] |
21617 | We can say propositions are bivalent, but vague utterances don't express a proposition [Williamson] |
21618 | If the vague 'TW is thin' says nothing, what does 'TW is thin if his perfect twin is thin' say? [Williamson] |
21590 | Asking when someone is 'clearly' old is higher-order vagueness [Williamson] |
21592 | Supervaluation keeps classical logic, but changes the truth in classical semantics [Williamson] |
21603 | You can't give a precise description of a language which is intrinsically vague [Williamson] |
21604 | Supervaluation assigns truth when all the facts are respected [Williamson] |
21607 | Supervaluation has excluded middle but not bivalence; 'A or not-A' is true, even when A is undecided [Williamson] |
21608 | Truth-functionality for compound statements fails in supervaluation [Williamson] |
21609 | Supervaluationism defines 'supertruth', but neglects it when defining 'valid' [Williamson] |
21610 | Supervaluation adds a 'definitely' operator to classical logic [Williamson] |
21613 | Supervaluationism cannot eliminate higher-order vagueness [Williamson] |
21633 | Nominalists suspect that properties etc are our projections, and could have been different [Williamson] |
21630 | If fuzzy edges are fine, then why not fuzzy temporal, modal or mereological boundaries? [Williamson] |
21632 | A river is not just event; it needs actual and counterfactual boundaries [Williamson] |
22142 | In future, only logical limits can be placed on divine omnipotence [Anon (Par), by Boulter] |
21621 | We can't infer metaphysical necessities to be a priori knowable - or indeed knowable in any way [Williamson] |
21627 | We have inexact knowledge when we include margins of error [Williamson] |
21626 | Knowing you know (KK) is usually denied if the knowledge concept is missing, or not considered [Williamson] |
16716 | It is heresy to require self-evident foundational principles in order to be certain [Anon (Par)] |
21631 | To know, believe, hope or fear, one must grasp the thought, but not when you fail to do them [Williamson] |
21600 | 'Blue' is not a family resemblance, because all the blues resemble in some respect [Williamson] |
21615 | References to the 'greatest prime number' have no reference, but are meaningful [Williamson] |
18038 | The 't' and 'f' of formal semantics has no philosophical interest, and may not refer to true and false [Williamson] |
22280 | Frege's account was top-down and decompositional, not bottom-up and compositional [Frege, by Potter] |
21624 | It is known that there is a cognitive loss in identifying propositions with possible worlds [Williamson] |
1866 | It is heresy to teach that history repeats every 36,000 years [Anon (Par)] |
1865 | It is heresy to teach that natural impossibilities cannot even be achieved by God [Anon (Par)] |
7741 | The predicate 'exists' is actually a natural language expression for a quantifier [Frege, by Weiner] |
1864 | It is heresy to teach that we can know God by his essence in this mortal life [Anon (Par)] |