16 ideas
| 9540 | A 'value-assignment' (V) is when to each variable in the set V assigns either the value 1 or the value 0 [Hughes/Cresswell] |
| 9541 | The Law of Transposition says (P→Q) → (¬Q→¬P) [Hughes/Cresswell] |
| 9543 | The rules preserve validity from the axioms, so no thesis negates any other thesis [Hughes/Cresswell] |
| 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] |
| 11026 | Classical logic is deliberately extensional, in order to model mathematics [Fitting] |
| 11028 | λ-abstraction disambiguates the scope of modal operators [Fitting] |
| 9544 | A system is 'weakly' complete if all wffs are derivable, and 'strongly' if theses are maximised [Hughes/Cresswell] |
| 17818 | How many? must first partition an aggregate into sets, and then logic fixes its number [Yourgrau] |
| 17822 | Nothing is 'intrinsically' numbered [Yourgrau] |
| 17817 | Defining 'three' as the principle of collection or property of threes explains set theory definitions [Yourgrau] |
| 17815 | We can't use sets as foundations for mathematics if we must await results from the upper reaches [Yourgrau] |
| 17821 | You can ask all sorts of numerical questions about any one given set [Yourgrau] |
| 15377 | Definite descriptions pick out different objects in different possible worlds [Fitting] |