20 ideas
15375 | If terms change their designations in different states, they are functions from states to objects [Fitting] |
15376 | Intensional logic adds a second type of quantification, over intensional objects, or individual concepts [Fitting] |
15378 | Awareness logic adds the restriction of an awareness function to epistemic logic [Fitting] |
15379 | Justication logics make explicit the reasons for mathematical truth in proofs [Fitting] |
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] |
13206 | A 'linear or total ordering' must be transitive and satisfy trichotomy [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] |
11026 | Classical logic is deliberately extensional, in order to model mathematics [Fitting] |
7746 | We don't normally think of names as having senses (e.g. we don't give definitions of them) [Searle] |
7747 | How can a proper name be correlated with its object if it hasn't got a sense? [Searle] |
7748 | 'Aristotle' means more than just 'an object that was christened "Aristotle"' [Searle] |
7749 | Reference for proper names presupposes a set of uniquely referring descriptions [Searle] |
7750 | Proper names are logically connected with their characteristics, in a loose way [Searle] |
11028 | λ-abstraction disambiguates the scope of modal operators [Fitting] |
15377 | Definite descriptions pick out different objects in different possible worlds [Fitting] |