127 ideas
| 12124 | Metaphysics is the best knowledge, because it is the simplest [Bacon] |
| 12123 | Natural history supports physical knowledge, which supports metaphysical knowledge [Bacon] |
| 12119 | Physics studies transitory matter; metaphysics what is abstracted and necessary [Bacon] |
| 12120 | Physics is of material and efficient causes, metaphysics of formal and final causes [Bacon] |
| 3426 | If one theory is reduced to another, we make fewer independent assumptions about the world [Kim] |
| 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] |
| 13654 | It is central to the iterative conception that membership is well-founded, with no infinite descending chains [Shapiro] |
| 13640 | Russell's paradox shows that there are classes which are not iterative sets [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] |
| 13627 | There is no 'correct' logic for natural languages [Shapiro] |
| 13642 | Logic is the ideal for learning new propositions on the basis of others [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] |
| 13667 | Skolem and Gödel championed first-order, and Zermelo, Hilbert, and Bernays championed higher-order [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] |
| 13626 | Semantic consequence is ineffective in second-order logic [Shapiro] |
| 13637 | If a logic is incomplete, its semantic consequence relation is not effective [Shapiro] |
| 13632 | Finding the logical form of a sentence is difficult, and there are no criteria of correctness [Shapiro] |
| 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] |
| 13636 | An axiomatization is 'categorical' if its models are isomorphic, so there is really only one interpretation [Shapiro] |
| 13670 | Categoricity can't be reached in a first-order language [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] |
| 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] |
| 3431 | Supervenience suggest dependence without reduction (e.g. beauty) [Kim] |
| 3437 | 'Physical facts determine all the facts' is the physicalists' slogan [Kim] |
| 3430 | Resemblance or similarity is the core of our concept of a property [Kim] |
| 3432 | Is weight a 'resultant' property of water, but transparency an 'emergent' property? [Kim] |
| 3434 | Emergent properties are 'brute facts' (inexplicable), but still cause things [Kim] |
| 13638 | Properties are often seen as intensional; equiangular and equilateral are different, despite identity of objects [Shapiro] |
| 3436 | Should properties be individuated by their causal powers? [Kim] |
| 3406 | Counterfactuals are either based on laws, or on nearby possible worlds [Kim, by PG] |
| 12121 | We don't assume there is no land, because we can only see sea [Bacon] |
| 12117 | Science moves up and down between inventions of causes, and experiments [Bacon] |
| 12127 | Many different theories will fit the observed facts [Bacon] |
| 3368 | Mind is basically qualities and intentionality, but how do they connect? [Kim] |
| 3392 | Mind is only interesting if it has causal powers [Kim] |
| 3396 | Experiment requires mental causation [Kim] |
| 3397 | Beliefs cause other beliefs [Kim] |
| 3367 | Both thought and language have intentionality [Kim] |
| 3365 | Intentionality involves both reference and content [Kim] |
| 3360 | Are pains pure qualia, or do they motivate? [Kim] |
| 3366 | Pain has no reference or content [Kim] |
| 3389 | Inverted qualia and zombies suggest experience isn't just functional [Kim] |
| 3391 | Crosswiring would show that pain and its function are separate [Kim, by PG] |
| 12126 | People love (unfortunately) extreme generality, rather than particular knowledge [Bacon] |
| 3422 | Externalism about content makes introspection depend on external evidence [Kim] |
| 3412 | How do we distinguish our anger from embarrassment? [Kim] |
| 3363 | We often can't decide what emotion, or even sensation, we are experiencing [Kim] |
| 3409 | Mental substance causation makes physics incomplete [Kim] |
| 3399 | If epiphenomenalism were true, we couldn't report consciousness [Kim] |
| 3390 | Are inverted or absent qualia coherent ideas? [Kim] |
| 3414 | What could demonstrate that zombies and inversion are impossible? [Kim] |
| 3359 | Cartesian dualism fails because it can't explain mental causation [Kim] |
| 3369 | Logical behaviourism translates mental language to behavioural [Kim] |
| 3428 | Behaviourism reduces mind to behaviour via bridging principles [Kim] |
| 3380 | Are dispositions real, or just a type of explanation? [Kim] |
| 3371 | Behaviour depends on lots of mental states together [Kim] |
| 3372 | Behaviour is determined by society as well as mental states [Kim] |
| 3373 | Snakes have different pain behaviour from us [Kim] |
| 3370 | What behaviour goes with mathematical beliefs? [Kim] |
| 3379 | Neurons seem to be very similar and interchangeable [Kim] |
| 3388 | Machine functionalism requires a Turing machine, causal-theoretical version doesn't [Kim] |
| 3384 | The person couldn't run Searle's Chinese Room without understanding Chinese [Kim] |
| 3393 | How do functional states give rise to mental causation? [Kim] |
| 3439 | Reductionism gets stuck with qualia [Kim] |
| 3427 | Reductionism is impossible if there aren't any 'bridge laws' between mental and physical [Kim] |
| 3376 | We can't assess evidence about mind without acknowledging phenomenal properties [Kim] |
| 3424 | Most modern physicalists are non-reductive property dualists [Kim] |
| 3362 | Supervenience says all souls are identical, being physically indiscernible [Kim] |
| 3413 | Zombies and inversion suggest non-reducible supervenience [Kim] |
| 3374 | Token physicalism isn't reductive; it just says all mental events have some physical properties [Kim] |
| 3433 | The core of the puzzle is the bridge laws between mind and brain [Kim] |
| 3377 | Elimination can either be by translation or by causal explanation [Kim] |
| 3438 | Reductionists deny new causal powers at the higher level [Kim] |
| 3440 | Without reductionism, mental causation is baffling [Kim] |
| 3375 | If an orange image is a brain state, are some parts of the brain orange? [Kim] |
| 3411 | How do we distinguish our attitudes from one another? [Kim] |
| 3386 | Folk psychology has been remarkably durable [Kim] |
| 3394 | Maybe folk psychology is a simulation, not a theory [Kim] |
| 3387 | A culture without our folk psychology would be quite baffling [Kim] |
| 3410 | Folk psychology has adapted to Freudianism [Kim] |
| 3382 | A machine with a mind might still fail the Turing Test [Kim] |
| 3383 | The Turing Test is too specifically human in its requirements [Kim] |
| 3408 | Two identical brain states could have different contents in different worlds [Kim] |
| 3420 | Two types of water are irrelevant to accounts of behaviour [Kim] |
| 3418 | 'Arthritis in my thigh' requires a social context for its content to be meaningful [Kim] |
| 3421 | Content is best thought of as truth conditions [Kim] |
| 3416 | Content may match several things in the environment [Kim] |
| 3419 | Pain, our own existence, and negative existentials, are not external [Kim] |
| 3417 | Content depends on other content as well as the facts [Kim] |
| 3403 | We assume people believe the obvious logical consequences of their known beliefs [Kim] |
| 3402 | If someone says "I do and don't like x", we don't assume a contradiction [Kim] |
| 12125 | Teleological accounts are fine in metaphysics, but they stop us from searching for the causes [Bacon] |
| 3401 | A common view is that causal connections must be instances of a law [Kim] |
| 3407 | Laws are either 'strict', or they involve a 'ceteris paribus' clause [Kim] |
| 12118 | Essences are part of first philosophy, but as part of nature, not part of logic [Bacon] |