25 ideas
| 8378 | Philosophers usually learn science from each other, not from science [Russell] |
| 19115 | You can 'rebut' an argument's conclusion, or 'undercut' its premises [Antonelli] |
| 10688 | 'Equivocation' is when terms do not mean the same thing in premises and conclusion [Beall/Restall] |
| 19119 | We infer that other objects are like some exceptional object, if they share some of its properties [Antonelli] |
| 19111 | Reasoning may be defeated by new premises, or by finding out more about the given ones [Antonelli] |
| 19114 | Should we accept Floating Conclusions, derived from two arguments in conflict? [Antonelli] |
| 19113 | Weakest Link Principle: prefer the argument whose weakest link is the stronger [Antonelli] |
| 19116 | Non-monotonic core: Reflexivity, Cut, Cautious Monotonicity, Left Logical Equivalence, Right Weakening [Antonelli] |
| 19117 | We can rank a formula by the level of surprise if it were to hold [Antonelli] |
| 19118 | People don't actually use classical logic, but may actually use non-monotonic logic [Antonelli] |
| 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] |
| 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] |
| 19110 | In classical logic the relation |= has Monotony built into its definition [Antonelli] |
| 19112 | Cautious Monotony ignores proved additions; Rational Monotony fails if the addition's negation is proved [Antonelli] |
| 10692 | Hilbert proofs have simple rules and complex axioms, and natural deduction is the opposite [Beall/Restall] |
| 8375 | 'Necessary' is a predicate of a propositional function, saying it is true for all values of its argument [Russell] |
| 4396 | The law of causality is a source of confusion, and should be dropped from philosophy [Russell] |
| 8376 | If causes are contiguous with events, only the last bit is relevant, or the event's timing is baffling [Russell] |
| 8380 | Striking a match causes its igniting, even if it sometimes doesn't work [Russell] |
| 8379 | In causal laws, 'events' must recur, so they have to be universals, not particulars [Russell] |
| 8381 | The constancy of scientific laws rests on differential equations, not on cause and effect [Russell] |