24 ideas
13206 | A 'linear or total ordering' must be transitive and satisfy trichotomy [Enderton] |
13201 | ∈ says the whole set is in the other; ⊆ says the members of the subset are in the other [Enderton] |
13204 | The 'ordered pair' <x,y> is defined to be {{x}, {x,y}} [Enderton] |
13200 | Note that {Φ} =/= Φ, because Φ ∈ {Φ} but Φ ∉ Φ [Enderton] |
13199 | The empty set may look pointless, but many sets can be constructed from it [Enderton] |
13203 | The singleton is defined using the pairing axiom (as {x,x}) [Enderton] |
13202 | Fraenkel added Replacement, to give a theory of ordinal numbers [Enderton] |
13205 | We can only define functions if Choice tells us which items are involved [Enderton] |
13134 | We negate predicates but do not negate names [Westerhoff] |
13117 | How far down before we are too specialised to have a category? [Westerhoff] |
13116 | Maybe objects in the same category have the same criteria of identity [Westerhoff] |
13118 | Categories are base-sets which are used to construct states of affairs [Westerhoff] |
13124 | Categories can be ordered by both containment and generality [Westerhoff] |
13125 | Categories are held to explain why some substitutions give falsehood, and others meaninglessness [Westerhoff] |
13126 | Categories systematize our intuitions about generality, substitutability, and identity [Westerhoff] |
13130 | Categories as generalities don't give a criterion for a low-level cut-off point [Westerhoff] |
13131 | The aim is that everything should belong in some ontological category or other [Westerhoff] |
13123 | All systems have properties and relations, and most have individuals, abstracta, sets and events [Westerhoff] |
13115 | Ontological categories are like formal axioms, not unique and with necessary membership [Westerhoff] |
13119 | Categories merely systematise, and are not intrinsic to objects [Westerhoff] |
13135 | A thing's ontological category depends on what else exists, so it is contingent [Westerhoff] |
14082 | No sortal could ever exactly pin down which set of particles count as this 'cup' [Schaffer,J] |
13129 | Essential kinds may be too specific to provide ontological categories [Westerhoff] |
14081 | Identities can be true despite indeterminate reference, if true under all interpretations [Schaffer,J] |