50 ideas
12223 | It is a fallacy to explain the obscure with the even more obscure [Hale/Wright] |
7791 | The simplest of the logics based on possible worlds is Lewis's S5 [Lewis,CI, by Girle] |
13030 | Extensionality: ∀x ∀y (∀z (z ∈ x ↔ z ∈ y) → x = y) [Kunen] |
13032 | Pairing: ∀x ∀y ∃z (x ∈ z ∧ y ∈ z) [Kunen] |
13033 | Union: ∀F ∃A ∀Y ∀x (x ∈ Y ∧ Y ∈ F → x ∈ A) [Kunen] |
13037 | Infinity: ∃x (0 ∈ x ∧ ∀y ∈ x (S(y) ∈ x) [Kunen] |
13038 | Power Set: ∀x ∃y ∀z(z ⊂ x → z ∈ y) [Kunen] |
13034 | Replacement: ∀x∈A ∃!y φ(x,y) → ∃Y ∀X∈A ∃y∈Y φ(x,y) [Kunen] |
13039 | Foundation:∀x(∃y(y∈x) → ∃y(y∈x ∧ ¬∃z(z∈x ∧ z∈y))) [Kunen] |
13036 | Choice: ∀A ∃R (R well-orders A) [Kunen] |
13029 | Set Existence: ∃x (x = x) [Kunen] |
13031 | Comprehension: ∃y ∀x (x ∈ y ↔ x ∈ z ∧ φ) [Kunen] |
13040 | Constructibility: V = L (all sets are constructible) [Kunen] |
9358 | There are several logics, none of which will ever derive falsehoods from truth [Lewis,CI] |
9357 | Excluded middle is just our preference for a simplified dichotomy in experience [Lewis,CI] |
9364 | Names represent a uniformity in experience, or they name nothing [Lewis,CI] |
12230 | Singular terms refer if they make certain atomic statements true [Hale/Wright] |
10631 | If 'x is heterological' iff it does not apply to itself, then 'heterological' is heterological if it isn't heterological [Hale/Wright] |
10624 | The incompletability of formal arithmetic reveals that logic also cannot be completely characterized [Hale/Wright] |
8784 | Neo-logicism founds arithmetic on Hume's Principle along with second-order logic [Hale/Wright] |
8787 | The Julius Caesar problem asks for a criterion for the concept of a 'number' [Hale/Wright] |
10629 | If structures are relative, this undermines truth-value and objectivity [Hale/Wright] |
10628 | The structural view of numbers doesn't fit their usage outside arithmetical contexts [Hale/Wright] |
8788 | Logicism is only noteworthy if logic has a privileged position in our ontology and epistemology [Hale/Wright] |
10622 | The neo-Fregean is more optimistic than Frege about contextual definitions of numbers [Hale/Wright] |
8783 | Logicism might also be revived with a quantificational approach, or an abstraction-free approach [Hale/Wright] |
12225 | Neo-Fregeanism might be better with truth-makers, rather than quantifier commitment [Hale/Wright] |
12224 | Are neo-Fregeans 'maximalists' - that everything which can exist does exist? [Hale/Wright] |
12226 | The identity of Pegasus with Pegasus may be true, despite the non-existence [Hale/Wright] |
18465 | An 'equivalence' relation is one which is reflexive, symmetric and transitive [Kunen] |
12229 | Maybe we have abundant properties for semantics, and sparse properties for ontology [Hale/Wright] |
18443 | A successful predicate guarantees the existence of a property - the way of being it expresses [Hale/Wright] |
10626 | Objects just are what singular terms refer to [Hale/Wright] |
11002 | Equating necessity with informal provability is the S4 conception of necessity [Lewis,CI, by Read] |
9362 | Necessary truths are those we will maintain no matter what [Lewis,CI] |
7803 | Modal logic began with translation difficulties for 'If...then' [Lewis,CI, by Girle] |
9365 | We can maintain a priori principles come what may, but we can also change them [Lewis,CI] |
21500 | We rely on memory for empirical beliefs because they mutually support one another [Lewis,CI] |
21501 | If we doubt memories we cannot assess our doubt, or what is being doubted [Lewis,CI] |
6556 | If anything is to be probable, then something must be certain [Lewis,CI] |
21498 | Congruents assertions increase the probability of each individual assertion in the set [Lewis,CI] |
5828 | Extension is the class of things, intension is the correct definition of the thing, and intension determines extension [Lewis,CI] |
9361 | We have to separate the mathematical from physical phenomena by abstraction [Lewis,CI] |
10630 | Abstracted objects are not mental creations, but depend on equivalence between given entities [Hale/Wright] |
8786 | One first-order abstraction principle is Frege's definition of 'direction' in terms of parallel lines [Hale/Wright] |
12227 | Abstractionism needs existential commitment and uniform truth-conditions [Hale/Wright] |
12228 | Equivalence abstraction refers to objects otherwise beyond our grasp [Hale/Wright] |
12231 | Reference needs truth as well as sense [Hale/Wright] |
10627 | Many conceptual truths ('yellow is extended') are not analytic, as derived from logic and definitions [Hale/Wright] |
9363 | Science seeks classification which will discover laws, essences, and predictions [Lewis,CI] |