7 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] |
9544 | A system is 'weakly' complete if all wffs are derivable, and 'strongly' if theses are maximised [Hughes/Cresswell] |
12733 | Because of the definitions of cause, effect and power, cause and effect have the same power [Leibniz] |
12734 | Every necessary proposition is demonstrable to someone who understands [Leibniz] |
18671 | The ground for an attitude is not a thing's 'goodness', but its concrete characteristics [Ewing] |