14 ideas
| 10688 | 'Equivocation' is when terms do not mean the same thing in premises and conclusion [Beall/Restall] |
| 10690 | Formal logic is invariant under permutations, or devoid of content, or gives the norms for thought [Beall/Restall] |
| 10691 | Logical consequence needs either proofs, or absence of counterexamples [Beall/Restall] |
| 10695 | Logical consequence is either necessary truth preservation, or preservation based on interpretation [Beall/Restall] |
| 10689 | A step is a 'material consequence' if we need contents as well as form [Beall/Restall] |
| 12219 | Whether a modal claim is true depends on how the object is described [Quine, by Fine,K] |
| 10922 | Objects are the values of variables, so a referentially opaque context cannot be quantified into [Quine] |
| 10696 | A 'logical truth' (or 'tautology', or 'theorem') follows from empty premises [Beall/Restall] |
| 10693 | Models are mathematical structures which interpret the non-logical primitives [Beall/Restall] |
| 10692 | Hilbert proofs have simple rules and complex axioms, and natural deduction is the opposite [Beall/Restall] |
| 10923 | Aristotelian essentialism says a thing has some necessary and some non-necessary properties [Quine] |
| 10921 | Necessity can attach to statement-names, to statements, and to open sentences [Quine] |
| 10924 | Necessity is in the way in which we say things, and not things themselves [Quine] |
| 5960 | When the soul is intelligent and harmonious, it is part of god and derives from god [Plutarch] |