92 ideas
| 12644 | Who cares what 'philosophy' is? Most pre-1950 thought doesn't now count as philosophy [Fodor] |
| 12633 | Definitions often give necessary but not sufficient conditions for an extension [Fodor] |
| 13634 | Satisfaction is 'truth in a model', which is a model of 'truth' [Shapiro] |
| 13643 | Aristotelian logic is complete [Shapiro] |
| 13651 | A set is 'transitive' if contains every member of each of its members [Shapiro] |
| 13647 | Choice is essential for proving downward Löwenheim-Skolem [Shapiro] |
| 13631 | Are sets part of logic, or part of mathematics? [Shapiro] |
| 13640 | Russell's paradox shows that there are classes which are not iterative sets [Shapiro] |
| 13654 | It is central to the iterative conception that membership is well-founded, with no infinite descending chains [Shapiro] |
| 13666 | Iterative sets are not Boolean; the complement of an iterative set is not an iterative sets [Shapiro] |
| 13653 | 'Well-ordering' of a set is an irreflexive, transitive, and binary relation with a least element [Shapiro] |
| 13642 | Logic is the ideal for learning new propositions on the basis of others [Shapiro] |
| 13627 | There is no 'correct' logic for natural languages [Shapiro] |
| 13667 | Skolem and Gödel championed first-order, and Zermelo, Hilbert, and Bernays championed higher-order [Shapiro] |
| 13668 | Bernays (1918) formulated and proved the completeness of propositional logic [Shapiro] |
| 13669 | Can one develop set theory first, then derive numbers, or are numbers more basic? [Shapiro] |
| 13662 | First-order logic was an afterthought in the development of modern logic [Shapiro] |
| 13624 | The 'triumph' of first-order logic may be related to logicism and the Hilbert programme, which failed [Shapiro] |
| 13660 | Maybe compactness, semantic effectiveness, and the Löwenheim-Skolem properties are desirable [Shapiro] |
| 13673 | The notion of finitude is actually built into first-order languages [Shapiro] |
| 15944 | Second-order logic is better than set theory, since it only adds relations and operations, and nothing else [Shapiro, by Lavine] |
| 13629 | Broad standard semantics, or Henkin semantics with a subclass, or many-sorted first-order semantics? [Shapiro] |
| 13650 | Henkin semantics has separate variables ranging over the relations and over the functions [Shapiro] |
| 13645 | In standard semantics for second-order logic, a single domain fixes the ranges for the variables [Shapiro] |
| 13649 | Completeness, Compactness and Löwenheim-Skolem fail in second-order standard semantics [Shapiro] |
| 13637 | If a logic is incomplete, its semantic consequence relation is not effective [Shapiro] |
| 13626 | Semantic consequence is ineffective in second-order logic [Shapiro] |
| 13632 | Finding the logical form of a sentence is difficult, and there are no criteria of correctness [Shapiro] |
| 12664 | A truth-table, not inferential role, defines 'and' [Fodor] |
| 12648 | Names in thought afford a primitive way to bring John before the mind [Fodor] |
| 12650 | 'Paderewski' has two names in mentalese, for his pianist file and his politician file [Fodor] |
| 13674 | We might reduce ontology by using truth of sentences and terms, instead of using objects satisfying models [Shapiro] |
| 13633 | 'Satisfaction' is a function from models, assignments, and formulas to {true,false} [Shapiro] |
| 13644 | Semantics for models uses set-theory [Shapiro] |
| 13670 | Categoricity can't be reached in a first-order language [Shapiro] |
| 13636 | An axiomatization is 'categorical' if its models are isomorphic, so there is really only one interpretation [Shapiro] |
| 13658 | Downward Löwenheim-Skolem: each satisfiable countable set always has countable models [Shapiro] |
| 13659 | Upward Löwenheim-Skolem: each infinite model has infinite models of all sizes [Shapiro] |
| 13648 | The Löwenheim-Skolem theorems show an explosion of infinite models, so 1st-order is useless for infinity [Shapiro] |
| 13675 | Substitutional semantics only has countably many terms, so Upward Löwenheim-Skolem trivially fails [Shapiro] |
| 12656 | P-and-Q gets its truth from the truth of P and truth of Q, but consistency isn't like that [Fodor] |
| 13635 | 'Weakly sound' if every theorem is a logical truth; 'sound' if every deduction is a semantic consequence [Shapiro] |
| 13628 | We can live well without completeness in logic [Shapiro] |
| 13630 | Non-compactness is a strength of second-order logic, enabling characterisation of infinite structures [Shapiro] |
| 13646 | Compactness is derived from soundness and completeness [Shapiro] |
| 13661 | A language is 'semantically effective' if its logical truths are recursively enumerable [Shapiro] |
| 13641 | Complex numbers can be defined as reals, which are defined as rationals, then integers, then naturals [Shapiro] |
| 13676 | Only higher-order languages can specify that 0,1,2,... are all the natural numbers that there are [Shapiro] |
| 13677 | Natural numbers are the finite ordinals, and integers are equivalence classes of pairs of finite ordinals [Shapiro] |
| 13652 | The 'continuum' is the cardinality of the powerset of a denumerably infinite set [Shapiro] |
| 13657 | First-order arithmetic can't even represent basic number theory [Shapiro] |
| 13656 | Some sets of natural numbers are definable in set-theory but not in arithmetic [Shapiro] |
| 13664 | Logicism is distinctive in seeking a universal language, and denying that logic is a series of abstractions [Shapiro] |
| 13625 | Mathematics and logic have no border, and logic must involve mathematics and its ontology [Shapiro] |
| 13663 | Some reject formal properties if they are not defined, or defined impredicatively [Shapiro] |
| 13638 | Properties are often seen as intensional; equiangular and equilateral are different, despite identity of objects [Shapiro] |
| 12653 | There's statistical, logical, nomological, conceptual and metaphysical possibility [Fodor] |
| 12651 | Some beliefs are only inferred when needed, like 'Shakespeare had not telephone' [Fodor] |
| 12628 | Knowing that must come before knowing how [Fodor] |
| 12625 | Pragmatism is the worst idea ever [Fodor] |
| 12636 | Mental states have causal powers [Fodor] |
| 12661 | The different types of resemblance don't resemble one another [Fodor] |
| 12632 | In the Representational view, concepts play the key linking role [Fodor] |
| 12624 | Only the labels of nodes have semantic content in connectionism, and they play no role [Fodor] |
| 12641 | Connectionism gives no account of how constituents make complex concepts [Fodor] |
| 12640 | Associative thinking avoids syntax, but can't preserve sense, reference or truth [Fodor] |
| 12643 | Ambiguities in English are the classic reason for claiming that we don't think in English [Fodor] |
| 12649 | We think in file names [Fodor] |
| 12647 | Mental representations name things in the world, but also files in our memory [Fodor] |
| 12655 | Frame Problem: how to eliminate most beliefs as irrelevant, without searching them? [Fodor] |
| 12630 | If concept content is reference, then my Twin and I are referring to the same stuff [Fodor] |
| 12658 | Nobody knows how concepts are acquired [Fodor] |
| 12662 | We have an innate capacity to form a concept, once we have grasped the stereotype [Fodor] |
| 12635 | Having a concept isn't a pragmatic matter, but being able to think about the concept [Fodor] |
| 12652 | Concepts have two sides; they are files that face thought, and also face subject-matter [Fodor] |
| 12626 | Cartesians put concept individuation before concept possession [Fodor] |
| 12637 | Frege's puzzles suggest to many that concepts have sense as well as reference [Fodor] |
| 12638 | If concepts have sense, we can't see the connection to their causal powers [Fodor] |
| 12639 | Belief in 'senses' may explain intentionality, but not mental processes [Fodor] |
| 12654 | You can't think 'brown dog' without thinking 'brown' and 'dog' [Fodor] |
| 12659 | Maybe stereotypes are a stage in concept acquisition (rather than a by-product) [Fodor] |
| 12660 | One stereotype might be a paradigm for two difference concepts [Fodor] |
| 12629 | For the referential view of thought, the content of a concept is just its reference [Fodor] |
| 12631 | Compositionality requires that concepts be atomic [Fodor] |
| 12657 | Abstractionism claims that instances provide criteria for what is shared [Fodor] |
| 12634 | 'Inferential-role semantics' says meaning is determined by role in inference [Fodor] |
| 12642 | Co-referring terms differ if they have different causal powers [Fodor] |
| 12663 | We refer to individuals and to properties, and we use singular terms and predicates [Fodor] |
| 12645 | Semantics (esp. referential semantics) allows inferences from utterances to the world [Fodor] |
| 12646 | Semantics relates to the world, so it is never just psychological [Fodor] |
| 12627 | Before you can plan action, you must decide on the truth of your estimate of success [Fodor] |
| 7903 | The six perfections are giving, morality, patience, vigour, meditation, and wisdom [Nagarjuna] |