52 ideas
7823 | Lucretius was rediscovered in 1417 [Grayling] |
9456 | Modal logic is multiple systems, shown in the variety of accessibility relations between worlds [Jacquette] |
7689 | The modal logic of C.I.Lewis was only interpreted by Kripke and Hintikka in the 1960s [Jacquette] |
18189 | ZFC could contain a contradiction, and it can never prove its own consistency [MacLane] |
9457 | The two main views in philosophy of logic are extensionalism and intensionalism [Jacquette] |
7681 | Logic describes inferences between sentences expressing possible properties of objects [Jacquette] |
9463 | Classical logic is bivalent, has excluded middle, and only quantifies over existent objects [Jacquette] |
7682 | Logic is not just about signs, because it relates to states of affairs, objects, properties and truth-values [Jacquette] |
7697 | On Russell's analysis, the sentence "The winged horse has wings" comes out as false [Jacquette] |
9466 | Nominalists like substitutional quantification to avoid the metaphysics of objects [Jacquette] |
9465 | Substitutional universal quantification retains truth for substitution of terms of the same type [Jacquette] |
9458 | Extensionalists say that quantifiers presuppose the existence of their objects [Jacquette] |
9461 | Intensionalists say meaning is determined by the possession of properties [Jacquette] |
7701 | Can a Barber shave all and only those persons who do not shave themselves? [Jacquette] |
6408 | Russell needed three extra axioms to reduce maths to logic: infinity, choice and reducibility [Grayling] |
7707 | To grasp being, we must say why something exists, and why there is one world [Jacquette] |
7692 | Being is maximal consistency [Jacquette] |
7687 | Existence is completeness and consistency [Jacquette] |
7679 | Ontology is the same as the conceptual foundations of logic [Jacquette] |
7678 | Ontology must include the minimum requirements for our semantics [Jacquette] |
7683 | Logic is based either on separate objects and properties, or objects as combinations of properties [Jacquette] |
7684 | Reduce states-of-affairs to object-property combinations, and possible worlds to states-of-affairs [Jacquette] |
7703 | If classes can't be eliminated, and they are property combinations, then properties (universals) can't be either [Jacquette] |
7685 | An object is a predication subject, distinguished by a distinctive combination of properties [Jacquette] |
7699 | Numbers, sets and propositions are abstract particulars; properties, qualities and relations are universals [Jacquette] |
7691 | The actual world is a consistent combination of states, made of consistent property combinations [Jacquette] |
7688 | The actual world is a maximally consistent combination of actual states of affairs [Jacquette] |
7695 | Do proposition-structures not associated with the actual world deserve to be called worlds? [Jacquette] |
7694 | We must experience the 'actual' world, which is defined by maximally consistent propositions [Jacquette] |
6414 | Two propositions might seem self-evident, but contradict one another [Grayling] |
7091 | The argument from analogy is not a strong inference, since the other being might be an actor or a robot [Grayling] |
7706 | If qualia supervene on intentional states, then intentional states are explanatorily fundamental [Jacquette] |
7704 | Reduction of intentionality involving nonexistent objects is impossible, as reduction must be to what is actual [Jacquette] |
9460 | Extensionalist semantics forbids reference to nonexistent objects [Jacquette] |
9459 | Extensionalist semantics is circular, as we must know the extension before assessing 'Fa' [Jacquette] |
7702 | The extreme views on propositions are Frege's Platonism and Quine's extreme nominalism [Jacquette] |
7293 | It is legitimate to do harm if it is the unintended side-effect of an effort to achieve a good [Grayling] |
7809 | In an honour code shame is the supreme punishment, and revenge is a duty [Grayling] |
23262 | Experience, sympathy and history are sensible grounds for laying claim to rights [Grayling] |
23263 | Politics is driven by power cliques [Grayling] |
23255 | It is essential for democracy that voting is free and well informed [Grayling] |
23254 | Democracies should require a supermajority for major questions [Grayling] |
23260 | A cap on time of service would restrict party control and career ambitions [Grayling] |
23253 | Majority decisions are only acceptable if the minority interests are not vital [Grayling] |
23256 | Liberty and equality cannot be reconciled [Grayling] |
23258 | The very concept of democracy entails a need for justice [Grayling] |
23259 | There should be separate legislative, executive and judicial institutions [Grayling] |
7292 | War must also have a good chance of success, and be waged with moderation [Grayling] |
7824 | If suicide is lawful, but assisting suicide is unlawful, powerless people are denied their rights [Grayling] |
7819 | Religion gives answers, comforts, creates social order, and panders to superstition [Grayling] |
7817 | To make an afterlife appealing, this life has to be denigrated [Grayling] |
7818 | In Greek mythology only heroes can go to heaven [Grayling] |