73 ideas
8092 | Logic was merely a branch of rhetoric until the scientific 17th century [Devlin] |
8081 | 'No councillors are bankers' and 'All bankers are athletes' implies 'Some athletes are not councillors' [Devlin] |
8085 | Modern propositional inference replaces Aristotle's 19 syllogisms with modus ponens [Devlin] |
8086 | Predicate logic retains the axioms of propositional logic [Devlin] |
10775 | The axiom of choice now seems acceptable and obvious (if it is meaningful) [Tharp] |
8091 | Situation theory is logic that takes account of context [Devlin] |
10766 | Logic is either for demonstration, or for characterizing structures [Tharp] |
8089 | Montague's intensional logic incorporated the notion of meaning [Devlin] |
8087 | Golden ages: 1900-1960 for pure logic, and 1950-1985 for applied logic [Devlin] |
22246 | A train of reasoning must be treated as all happening simultaneously [Recanati] |
10767 | Elementary logic is complete, but cannot capture mathematics [Tharp] |
10769 | Second-order logic isn't provable, but will express set-theory and classic problems [Tharp] |
8082 | Where a conditional is purely formal, an implication implies a link between premise and conclusion [Devlin] |
8072 | Sentences of apparent identical form can have different contextual meanings [Devlin] |
10762 | In sentential logic there is a simple proof that all truth functions can be reduced to 'not' and 'and' [Tharp] |
16357 | Mental files are the counterparts of singular terms [Recanati] |
10776 | The main quantifiers extend 'and' and 'or' to infinite domains [Tharp] |
10774 | There are at least five unorthodox quantifiers that could be used [Tharp] |
10773 | The Löwenheim-Skolem property is a limitation (e.g. can't say there are uncountably many reals) [Tharp] |
10777 | Skolem mistakenly inferred that Cantor's conceptions were illusory [Tharp] |
10765 | Soundness would seem to be an essential requirement of a proof procedure [Tharp] |
10763 | Completeness and compactness together give axiomatizability [Tharp] |
10770 | If completeness fails there is no algorithm to list the valid formulas [Tharp] |
10771 | Compactness is important for major theories which have infinitely many axioms [Tharp] |
10772 | Compactness blocks infinite expansion, and admits non-standard models [Tharp] |
10764 | A complete logic has an effective enumeration of the valid formulas [Tharp] |
10768 | Effective enumeration might be proved but not specified, so it won't guarantee knowledge [Tharp] |
8075 | Space and time are atomic in the arrow, and divisible in the tortoise [Devlin] |
16360 | Identity statements are informative if they link separate mental files [Recanati] |
16374 | There is a continuum from acquaintance to description in knowledge, depending on the link [Recanati] |
8088 | People still say the Hopi have no time concepts, despite Whorf's later denial [Devlin] |
18409 | Indexicals apply to singular thought, and mental files have essentially indexical features [Recanati] |
16354 | Indexicality is closely related to singularity, exploiting our direct relations with things [Recanati] |
22247 | Indexicality is not just a feature of language; examples show it also occurs in thought [Recanati] |
22248 | How can we communicate indexical thoughts to people not in the right context? [Recanati] |
16371 | Files can be confused, if two files correctly have a single name, or one file has two names [Recanati] |
16373 | Encylopedic files have further epistemic links, beyond the basic one [Recanati] |
16375 | Singular thoughts need a mental file, and an acquaintance relation from file to object [Recanati] |
16377 | Expected acquaintance can create a thought-vehicle file, but without singular content [Recanati] |
16378 | An 'indexed' file marks a file which simulates the mental file of some other person [Recanati] |
16387 | Reference by mental files is Millian, in emphasising acquaintance, rather than satisfaction [Recanati] |
16361 | A mental file treats all of its contents as concerning one object [Recanati] |
16358 | The reference of a file is fixed by what it relates to, not the information it contains [Recanati] |
16367 | There are transient 'demonstrative' files, habitual 'recognitional' files, cumulative 'encyclopedic' files [Recanati] |
16368 | Files are hierarchical: proto-files, then first-order, then higher-order encyclopedic [Recanati] |
16370 | A file has a 'nucleus' through its relation to the object, and a 'periphery' of links to other files [Recanati] |
22242 | Mental files are concepts, which are either collections or (better) containers [Recanati] |
22243 | The Frege case of believing a thing is both F and not-F is explained by separate mental files [Recanati] |
16381 | The content of thought is what is required to understand it (which involves hearers) [Recanati] |
16365 | Mental files are individual concepts (thought constituents) [Recanati] |
16356 | There may be two types of reference in language and thought: descriptive and direct [Recanati] |
16393 | In super-direct reference, the referent serves as its own vehicle of reference [Recanati] |
16386 | Direct reference is strong Millian (just a tag) or weak Kaplanian (allowing descriptions as well) [Recanati] |
16372 | Sense determines reference says same sense/same reference; new reference means new sense [Recanati] |
16388 | We need sense as well as reference, but in a non-descriptive form, and mental files do that [Recanati] |
16359 | Sense is a mental file (not its contents); similar files for Cicero and Tully are two senses [Recanati] |
16355 | Problems with descriptivism are reference by perception, by communications and by indexicals [Recanati] |
16348 | Descriptivism says we mentally relate to objects through their properties [Recanati] |
16384 | Definite descriptions reveal either a predicate (attributive use) or the file it belongs in (referential) [Recanati] |
16352 | A rigid definite description can be attributive, not referential: 'the actual F, whoever he is….' [Recanati] |
22245 | A linguistic expression refers to what its associated mental file refers to [Recanati] |
16353 | Singularity cannot be described, and it needs actual world relations [Recanati] |
8073 | How do we parse 'time flies like an arrow' and 'fruit flies like an apple'? [Devlin] |
16382 | Fregean modes of presentation can be understood as mental files [Recanati] |
16389 | If two people think 'I am tired', they think the same thing, and they think different things [Recanati] |
16363 | Indexicals (like mental files) determine their reference relationally, not by satisfaction [Recanati] |
16364 | Indexical don't refer; only their tokens do [Recanati] |
16351 | In 2-D semantics, reference is determined, then singularity by the truth of a predication [Recanati] |
16350 | Two-D semantics is said to help descriptivism of reference deal with singular objects [Recanati] |
8076 | The distinction between sentences and abstract propositions is crucial in logic [Devlin] |
16380 | Russellian propositions are better than Fregean thoughts, by being constant through communication [Recanati] |
22250 | There are speakers' thoughts and hearers' thoughts, but no further thought attached to the utterance [Recanati] |
22249 | The Naive view of communication is that hearers acquire exactly the thoughts of the speaker [Recanati] |