55 ideas
| 11051 | Frege's logical approach dominates the analytical tradition [Hanna] |
| 11054 | Scientism says most knowledge comes from the exact sciences [Hanna] |
| 11070 | 'Denying the antecedent' fallacy: φ→ψ, ¬φ, so ¬ψ [Hanna] |
| 11071 | 'Affirming the consequent' fallacy: φ→ψ, ψ, so φ [Hanna] |
| 11088 | We can list at least fourteen informal fallacies [Hanna] |
| 11059 | Circular arguments are formally valid, though informally inadmissible [Hanna] |
| 11089 | Formally, composition and division fallacies occur in mereology [Hanna] |
| 9542 | The best known axiomatization of PL is Whitehead/Russell, with four axioms and two rules [Russell/Whitehead, by Hughes/Cresswell] |
| 21720 | Russell saw Reducibility as legitimate for reducing classes to logic [Linsky,B on Russell/Whitehead] |
| 10044 | Russell denies extensional sets, because the null can't be a collection, and the singleton is just its element [Russell/Whitehead, by Shapiro] |
| 18208 | We regard classes as mere symbolic or linguistic conveniences [Russell/Whitehead] |
| 11058 | Logic is explanatorily and ontologically dependent on rational animals [Hanna] |
| 11072 | Logic is personal and variable, but it has a universal core [Hanna] |
| 11061 | Intensional consequence is based on the content of the concepts [Hanna] |
| 8204 | Lewis's 'strict implication' preserved Russell's confusion of 'if...then' with implication [Quine on Russell/Whitehead] |
| 9359 | Russell's implication means that random sentences imply one another [Lewis,CI on Russell/Whitehead] |
| 21707 | Russell unusually saw logic as 'interpreted' (though very general, and neutral) [Russell/Whitehead, by Linsky,B] |
| 10036 | In 'Principia' a new abstract theory of relations appeared, and was applied [Russell/Whitehead, by Gödel] |
| 18248 | A real number is the class of rationals less than the number [Russell/Whitehead, by Shapiro] |
| 18152 | Russell takes numbers to be classes, but then reduces the classes to numerical quantifiers [Russell/Whitehead, by Bostock] |
| 10025 | Russell and Whitehead took arithmetic to be higher-order logic [Russell/Whitehead, by Hodes] |
| 8683 | Russell and Whitehead were not realists, but embraced nearly all of maths in logic [Russell/Whitehead, by Friend] |
| 10037 | 'Principia' lacks a precise statement of the syntax [Gödel on Russell/Whitehead] |
| 10093 | The ramified theory of types used propositional functions, and covered bound variables [Russell/Whitehead, by George/Velleman] |
| 8691 | The Russell/Whitehead type theory was limited, and was not really logic [Friend on Russell/Whitehead] |
| 10305 | In 'Principia Mathematica', logic is exceeded in the axioms of infinity and reducibility, and in the domains [Bernays on Russell/Whitehead] |
| 11063 | Logicism struggles because there is no decent theory of analyticity [Hanna] |
| 8684 | Russell and Whitehead consider the paradoxes to indicate that we create mathematical reality [Russell/Whitehead, by Friend] |
| 8746 | To avoid vicious circularity Russell produced ramified type theory, but Ramsey simplified it [Russell/Whitehead, by Shapiro] |
| 11055 | Supervenience can add covariation, upward dependence, and nomological connection [Hanna] |
| 12033 | An object is identical with itself, and no different indiscernible object can share that [Russell/Whitehead, by Adams,RM] |
| 11083 | A sentence is necessary if it is true in a set of worlds, and nonfalse in the other worlds [Hanna] |
| 11086 | Metaphysical necessity can be 'weak' (same as logical) and 'strong' (based on essences) [Hanna] |
| 11084 | Logical necessity is truth in all logically possible worlds, because of laws and concepts [Hanna] |
| 11085 | Nomological necessity is truth in all logically possible worlds with our laws [Hanna] |
| 10040 | Russell showed, through the paradoxes, that our basic logical intuitions are self-contradictory [Russell/Whitehead, by Gödel] |
| 11077 | Intuition includes apriority, clarity, modality, authority, fallibility and no inferences [Hanna] |
| 11080 | Intuition is more like memory, imagination or understanding, than like perception [Hanna] |
| 11078 | Intuition is only outside the 'space of reasons' if all reasons are inferential [Hanna] |
| 11053 | Explanatory reduction is stronger than ontological reduction [Hanna] |
| 11081 | Imagination grasps abstracta, generates images, and has its own correctness conditions [Hanna] |
| 11082 | Should we take the 'depictivist' or the 'descriptivist/propositionalist' view of mental imagery? [Hanna] |
| 11067 | Rational animals have a normative concept of necessity [Hanna] |
| 11068 | One tradition says talking is the essence of rationality; the other says the essence is logic [Hanna] |
| 11047 | Hegelian holistic rationality is the capacity to seek coherence [Hanna] |
| 11048 | Humean Instrumental rationality is the capacity to seek contingent truths [Hanna] |
| 11046 | Kantian principled rationality is recognition of a priori universal truths [Hanna] |
| 21725 | The multiple relations theory says assertions about propositions are about their ingredients [Russell/Whitehead, by Linsky,B] |
| 23474 | A judgement is a complex entity, of mind and various objects [Russell/Whitehead] |
| 23455 | The meaning of 'Socrates is human' is completed by a judgement [Russell/Whitehead] |
| 23480 | The multiple relation theory of judgement couldn't explain the unity of sentences [Morris,M on Russell/Whitehead] |
| 18275 | Only the act of judging completes the meaning of a statement [Russell/Whitehead] |
| 11045 | Most psychologists are now cognitivists [Hanna] |
| 21650 | No language is semantically referential; it all occurs at the level of thought or utterance [Pietroski, by Hofweber] |
| 23453 | Propositions as objects of judgement don't exist, because we judge several objects, not one [Russell/Whitehead] |