111 ideas
| 19693 | There is practical wisdom (for action), and theoretical wisdom (for deep understanding) [Aristotle, by Whitcomb] |
| 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] |
| 1575 | For Aristotle logos is essentially the ability to talk rationally about questions of value [Roochnik on Aristotle] |
| 1589 | Aristotle is the supreme optimist about the ability of logos to explain nature [Roochnik on Aristotle] |
| 8200 | Aristotelian definitions aim to give the essential properties of the thing defined [Aristotle, by Quine] |
| 4385 | Aristotelian definition involves first stating the genus, then the differentia of the thing [Aristotle, by Urmson] |
| 13689 | 'Theorems' are formulas provable from no premises at all [Sider] |
| 13705 | Truth tables assume truth functionality, and are just pictures of truth functions [Sider] |
| 13710 | In D we add that 'what is necessary is possible'; then tautologies are possible, and contradictions not necessary [Sider] |
| 13706 | Intuitively, deontic accessibility seems not to be reflexive, but to be serial [Sider] |
| 13711 | System B introduces iterated modalities [Sider] |
| 13708 | S5 is the strongest system, since it has the most valid formulas, because it is easy to be S5-valid [Sider] |
| 13712 | Epistemic accessibility is reflexive, and allows positive and negative introspection (KK and K¬K) [Sider] |
| 13714 | We can treat modal worlds as different times [Sider] |
| 13720 | Converse Barcan Formula: □∀αφ→∀α□φ [Sider] |
| 13718 | The Barcan Formula ∀x□Fx→□∀xFx may be a defect in modal logic [Sider] |
| 13723 | System B is needed to prove the Barcan Formula [Sider] |
| 13715 | You can employ intuitionist logic without intuitionism about mathematics [Sider] |
| 13282 | Aristotle relativises the notion of wholeness to different measures [Aristotle, by Koslicki] |
| 13680 | Maybe logical consequence is a primitive notion [Sider] |
| 13679 | Maybe logical consequence is more a matter of provability than of truth-preservation [Sider] |
| 13678 | The most popular account of logical consequence is the semantic or model-theoretic one [Sider] |
| 13682 | Maybe logical consequence is impossibility of the premises being true and the consequent false [Sider] |
| 13722 | A 'theorem' is an axiom, or the last line of a legitimate proof [Sider] |
| 4730 | For Aristotle, the subject-predicate structure of Greek reflected a substance-accident structure of reality [Aristotle, by O'Grady] |
| 12664 | A truth-table, not inferential role, defines 'and' [Fodor] |
| 13696 | When a variable is 'free' of the quantifier, the result seems incapable of truth or falsity [Sider] |
| 13700 | A 'total' function must always produce an output for a given domain [Sider] |
| 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] |
| 13703 | λ can treat 'is cold and hungry' as a single predicate [Sider] |
| 13687 | No assumptions in axiomatic proofs, so no conditional proof or reductio [Sider] |
| 13688 | Good axioms should be indisputable logical truths [Sider] |
| 13691 | Induction has a 'base case', then an 'inductive hypothesis', and then the 'inductive step' [Sider] |
| 13690 | Proof by induction 'on the length of the formula' deconstructs a formula into its accepted atoms [Sider] |
| 13685 | Natural deduction helpfully allows reasoning with assumptions [Sider] |
| 13686 | We can build proofs just from conclusions, rather than from plain formulae [Sider] |
| 13697 | Valuations in PC assign truth values to formulas relative to variable assignments [Sider] |
| 13684 | The semantical notion of a logical truth is validity, being true in all interpretations [Sider] |
| 13704 | It is hard to say which are the logical truths in modal logic, especially for iterated modal operators [Sider] |
| 13724 | In model theory, first define truth, then validity as truth in all models, and consequence as truth-preservation [Sider] |
| 12656 | P-and-Q gets its truth from the truth of P and truth of Q, but consistency isn't like that [Fodor] |
| 13698 | In a complete logic you can avoid axiomatic proofs, by using models to show consequences [Sider] |
| 13699 | Compactness surprisingly says that no contradictions can emerge when the set goes infinite [Sider] |
| 13701 | A single second-order sentence validates all of arithmetic - but this can't be proved axiomatically [Sider] |
| 13692 | A 'precisification' of a trivalent interpretation reduces it to a bivalent interpretation [Sider] |
| 13693 | A 'supervaluation' assigns further Ts and Fs, if they have been assigned in every precisification [Sider] |
| 13695 | Supervaluational logic is classical, except when it adds the 'Definitely' operator [Sider] |
| 13694 | We can 'sharpen' vague terms, and then define truth as true-on-all-sharpenings [Sider] |
| 13683 | A relation is a feature of multiple objects taken together [Sider] |
| 13276 | The unmoved mover and the soul show Aristotelian form as the ultimate mereological atom [Aristotle, by Koslicki] |
| 13277 | The 'form' is the recipe for building wholes of a particular kind [Aristotle, by Koslicki] |
| 13702 | The identity of indiscernibles is necessarily true, if being a member of some set counts as a property [Sider] |
| 13721 | 'Strong' necessity in all possible worlds; 'weak' necessity in the worlds where the relevant objects exist [Sider] |
| 13707 | Maybe metaphysical accessibility is intransitive, if a world in which I am a frog is impossible [Sider] |
| 13709 | Logical truths must be necessary if anything is [Sider] |
| 12653 | There's statistical, logical, nomological, conceptual and metaphysical possibility [Fodor] |
| 13716 | 'If B hadn't shot L someone else would have' if false; 'If B didn't shoot L, someone else did' is true [Sider] |
| 13717 | Transworld identity is not a problem in de dicto sentences, which needn't identify an individual [Sider] |
| 13719 | Barcan Formula problem: there might have been a ghost, despite nothing existing which could be a ghost [Sider] |
| 5991 | For Aristotle, knowledge is of causes, and is theoretical, practical or productive [Aristotle, by Code] |
| 12651 | Some beliefs are only inferred when needed, like 'Shakespeare had not telephone' [Fodor] |
| 12628 | Knowing that must come before knowing how [Fodor] |
| 11239 | The notion of a priori truth is absent in Aristotle [Aristotle, by Politis] |
| 23312 | Aristotle is a rationalist, but reason is slowly acquired through perception and experience [Aristotle, by Frede,M] |
| 12625 | Pragmatism is the worst idea ever [Fodor] |
| 16111 | Aristotle wants to fit common intuitions, and therefore uses language as a guide [Aristotle, by Gill,ML] |
| 16971 | Plato says sciences are unified around Forms; Aristotle says they're unified around substance [Aristotle, by Moravcsik] |
| 11243 | Aristotelian explanations are facts, while modern explanations depend on human conceptions [Aristotle, by Politis] |
| 3320 | Aristotle's standard analysis of species and genus involves specifying things in terms of something more general [Aristotle, by Benardete,JA] |
| 12000 | Aristotle regularly says that essential properties explain other significant properties [Aristotle, by Kung] |
| 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] |
| 12640 | Associative thinking avoids syntax, but can't preserve sense, reference or truth [Fodor] |
| 12641 | Connectionism gives no account of how constituents make complex concepts [Fodor] |
| 23300 | Aristotle and the Stoics denied rationality to animals, while Platonists affirmed it [Aristotle, by Sorabji] |
| 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] |
| 11240 | The notion of analytic truth is absent in Aristotle [Aristotle, by Politis] |
| 12627 | Before you can plan action, you must decide on the truth of your estimate of success [Fodor] |
| 6559 | Aristotle never actually says that man is a rational animal [Aristotle, by Fogelin] |
| 11150 | It is the mark of an educated mind to be able to entertain an idea without accepting it [Aristotle] |
| 3037 | Aristotle said the educated were superior to the uneducated as the living are to the dead [Aristotle, by Diog. Laertius] |
| 8660 | There are potential infinities (never running out), but actual infinity is incoherent [Aristotle, by Friend] |
| 12058 | Aristotle's matter can become any other kind of matter [Aristotle, by Wiggins] |
| 22729 | The concepts of gods arose from observing the soul, and the cosmos [Aristotle, by Sext.Empiricus] |