75 ideas
| 9108 | From an impossibility anything follows [William of Ockham] |
| 16676 | Why use more things when fewer will do? [William of Ockham] |
| 6806 | Do not multiply entities beyond necessity [William of Ockham] |
| 9107 | A proposition is true if its subject and predicate stand for the same thing [William of Ockham] |
| 16300 | Ockham had an early axiomatic account of truth [William of Ockham, by Halbach] |
| 15413 | With four tense operators, all complex tenses reduce to fourteen basic cases [Burgess] |
| 15415 | The temporal Barcan formulas fix what exists, which seems absurd [Burgess] |
| 15430 | Is classical logic a part of intuitionist logic, or vice versa? [Burgess] |
| 15431 | It is still unsettled whether standard intuitionist logic is complete [Burgess] |
| 15429 | Relevance logic's → is perhaps expressible by 'if A, then B, for that reason' [Burgess] |
| 15404 | Technical people see logic as any formal system that can be studied, not a study of argument validity [Burgess] |
| 15405 | Classical logic neglects the non-mathematical, such as temporality or modality [Burgess] |
| 15427 | The Cut Rule expresses the classical idea that entailment is transitive [Burgess] |
| 15421 | Classical logic neglects counterfactuals, temporality and modality, because maths doesn't use them [Burgess] |
| 15403 | Philosophical logic is a branch of logic, and is now centred in computer science [Burgess] |
| 15407 | Formalising arguments favours lots of connectives; proving things favours having very few [Burgess] |
| 15424 | Asserting a disjunction from one disjunct seems odd, but can be sensible, and needed in maths [Burgess] |
| 15409 | All occurrences of variables in atomic formulas are free [Burgess] |
| 15414 | The denotation of a definite description is flexible, rather than rigid [Burgess] |
| 9106 | The word 'every' only signifies when added to a term such as 'man', referring to all men [William of Ockham] |
| 15406 | 'Induction' and 'recursion' on complexity prove by connecting a formula to its atomic components [Burgess] |
| 15425 | The sequent calculus makes it possible to have proof without transitivity of entailment [Burgess] |
| 15426 | We can build one expanding sequence, instead of a chain of deductions [Burgess] |
| 15408 | 'Tautologies' are valid formulas of classical sentential logic - or substitution instances in other logics [Burgess] |
| 15418 | Validity (for truth) and demonstrability (for proof) have correlates in satisfiability and consistency [Burgess] |
| 15412 | Models leave out meaning, and just focus on truth values [Burgess] |
| 15411 | We only need to study mathematical models, since all other models are isomorphic to these [Burgess] |
| 15416 | We aim to get the technical notion of truth in all models matching intuitive truth in all instances [Burgess] |
| 15428 | The Liar seems like a truth-value 'gap', but dialethists see it as a 'glut' [Burgess] |
| 10185 | Set theory is the standard background for modern mathematics [Burgess] |
| 10184 | Structuralists take the name 'R' of the reals to be a variable ranging over structures, not a structure [Burgess] |
| 10189 | There is no one relation for the real number 2, as relations differ in different models [Burgess] |
| 10186 | If set theory is used to define 'structure', we can't define set theory structurally [Burgess] |
| 10187 | Abstract algebra concerns relations between models, not common features of all the models [Burgess] |
| 10188 | How can mathematical relations be either internal, or external, or intrinsic? [Burgess] |
| 9113 | Just as unity is not a property of a single thing, so numbers are not properties of many things [William of Ockham] |
| 9110 | The words 'thing' and 'to be' assert the same idea, as a noun and as a verb [William of Ockham] |
| 16608 | Ockham was an anti-realist about the categories [William of Ockham, by Pasnau] |
| 16654 | Our words and concepts don't always correspond to what is out there [William of Ockham] |
| 18529 | Relations are expressed either as absolute facts, or by a relational concept [William of Ockham] |
| 22132 | Species and genera are individual concepts which naturally signify many individuals [William of Ockham] |
| 9103 | A universal is not a real feature of objects, but only a thought-object in the mind [William of Ockham] |
| 15388 | Universals are single things, and only universal in what they signify [William of Ockham] |
| 16779 | Cut wood doesn't make a new substance, but seems to make separate subjects [William of Ockham] |
| 16757 | Hot water naturally cools down, which is due to the substantial form of the water [William of Ockham] |
| 16599 | Ockham says matter must be extended, so we don't need Quantity [William of Ockham, by Pasnau] |
| 16681 | Matter gets its quantity from condensation and rarefaction, which is just local motion [William of Ockham] |
| 9109 | If essence and existence were two things, one could exist without the other, which is impossible [William of Ockham] |
| 16792 | If parts change, the whole changes [William of Ockham] |
| 15420 | De re modality seems to apply to objects a concept intended for sentences [Burgess] |
| 15419 | General consensus is S5 for logical modality of validity, and S4 for proof [Burgess] |
| 15417 | Logical necessity has two sides - validity and demonstrability - which coincide in classical logic [Burgess] |
| 15422 | Three conditionals theories: Materialism (material conditional), Idealism (true=assertable), Nihilism (no truth) [Burgess] |
| 15423 | It is doubtful whether the negation of a conditional has any clear meaning [Burgess] |
| 9089 | Knowledge is a quality existing subjectively in the soul [William of Ockham] |
| 9091 | Sometimes 'knowledge' just concerns the conclusion, sometimes the whole demonstration [William of Ockham] |
| 9100 | Our intellect only assents to what we believe to be true [William of Ockham] |
| 9090 | Knowledge is certain cognition of something that is true [William of Ockham] |
| 9101 | Abstractive cognition knows universals abstracted from many singulars [William of Ockham] |
| 9102 | If an animal approached from a distance, we might abstract 'animal' from one instance [William of Ockham] |
| 2170 | Homer does not distinguish between soul and body [Homer, by Williams,B] |
| 9114 | There are no secure foundations to prove the separate existence of mind, in reason or experience [William of Ockham] |
| 9104 | A universal is the result of abstraction, which is only a kind of mental picturing [William of Ockham] |
| 9105 | Some concepts for propositions exist only in the mind, and in no language [William of Ockham] |
| 2171 | The 'will' doesn't exist; there is just conclusion, then action [Homer, by Williams,B] |
| 21819 | Plato says the Good produces the Intellectual-Principle, which in turn produces the Soul [Homer, by Plotinus] |
| 11388 | Let there be one ruler [Homer] |
| 16675 | Every extended material substance is composed of parts distant from one another [William of Ockham] |
| 19381 | The past has ceased to exist, and the future does not yet exist, so time does not exist [William of Ockham] |
| 9111 | God is not wise, but more-than-wise; God is not good, but more-than-good [William of Ockham] |
| 8010 | William of Ockham is the main spokesman for God's commands being the source of morality [William of Ockham] |
| 9112 | We could never form a concept of God's wisdom if we couldn't abstract it from creatures [William of Ockham] |
| 14829 | Homer so enjoys the company of the gods that he must have been deeply irreligious [Homer, by Nietzsche] |
| 9115 | To love God means to love whatever God wills to be loved [William of Ockham] |
| 16679 | Even an angel must have some location [William of Ockham, by Pasnau] |