15 ideas
18901 | Truthmakers are facts 'of' a domain, not something 'in' the domain [Sommers] |
18904 | 'Predicable' terms come in charged pairs, with one the negation of the other [Sommers, by Engelbretsen] |
18895 | Logic which maps ordinary reasoning must be transparent, and free of variables [Sommers] |
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] |
18897 | Predicate logic has to spell out that its identity relation '=' is an equivalent relation [Sommers] |
18893 | Translating into quantificational idiom offers no clues as to how ordinary thinkers reason [Sommers] |
18903 | Sommers promotes the old idea that negation basically refers to terms [Sommers, by Engelbretsen] |
18894 | Predicates form a hierarchy, from the most general, down to names at the bottom [Sommers] |
9544 | A system is 'weakly' complete if all wffs are derivable, and 'strongly' if theses are maximised [Hughes/Cresswell] |
18900 | Unfortunately for realists, modern logic cannot say that some fact exists [Sommers] |
13127 | Categories can't overlap; they are either disjoint, or inclusive [Sommers, by Westerhoff] |
18898 | In standard logic, names are the only way to refer [Sommers] |
6005 | Animals are dangerous and nourishing, and can't form contracts of justice [Hermarchus, by Sedley] |