61 ideas
| 22285 | Impredicative definitions are circular, but fine for picking out, rather than creating something [Potter] |
| 22301 | The Identity Theory says a proposition is true if it coincides with what makes it true [Potter] |
| 22324 | It has been unfortunate that externalism about truth is equated with correspondence [Potter] |
| 10702 | Set theory's three roles: taming the infinite, subject-matter of mathematics, and modes of reasoning [Potter] |
| 10713 | Usually the only reason given for accepting the empty set is convenience [Potter] |
| 13044 | Infinity: There is at least one limit level [Potter] |
| 10676 | The Axiom of Choice is a non-logical principle of set-theory [Hossack] |
| 10686 | The Axiom of Choice guarantees a one-one correspondence from sets to ordinals [Hossack] |
| 23623 | Predicativism says only predicated sets exist [Hossack] |
| 23624 | The iterative conception has to appropriate Replacement, to justify the ordinals [Hossack] |
| 10708 | Nowadays we derive our conception of collections from the dependence between them [Potter] |
| 13546 | The 'limitation of size' principles say whether properties collectivise depends on the number of objects [Potter] |
| 23625 | Limitation of Size justifies Replacement, but then has to appropriate Power Set [Hossack] |
| 10687 | Maybe we reduce sets to ordinals, rather than the other way round [Hossack] |
| 10707 | Mereology elides the distinction between the cards in a pack and the suits [Potter] |
| 10677 | Extensional mereology needs two definitions and two axioms [Hossack] |
| 10704 | We can formalize second-order formation rules, but not inference rules [Potter] |
| 22279 | Frege's sign |--- meant judgements, but the modern |- turnstile means inference, with intecedents [Potter] |
| 22291 | Deductivism can't explain how the world supports unconditional conclusions [Potter] |
| 23628 | The connective 'and' can have an order-sensitive meaning, as 'and then' [Hossack] |
| 23627 | 'Before' and 'after' are not two relations, but one relation with two orders [Hossack] |
| 10671 | Plural definite descriptions pick out the largest class of things that fit the description [Hossack] |
| 10666 | Plural reference will refer to complex facts without postulating complex things [Hossack] |
| 10669 | Plural reference is just an abbreviation when properties are distributive, but not otherwise [Hossack] |
| 10675 | A plural comprehension principle says there are some things one of which meets some condition [Hossack] |
| 10703 | Supposing axioms (rather than accepting them) give truths, but they are conditional [Potter] |
| 22295 | Modern logical truths are true under all interpretations of the non-logical words [Potter] |
| 10673 | Plural language can discuss without inconsistency things that are not members of themselves [Hossack] |
| 10680 | The theory of the transfinite needs the ordinal numbers [Hossack] |
| 10684 | I take the real numbers to be just lengths [Hossack] |
| 10712 | If set theory didn't found mathematics, it is still needed to count infinite sets [Potter] |
| 23626 | Transfinite ordinals are needed in proof theory, and for recursive functions and computability [Hossack] |
| 17882 | It is remarkable that all natural number arithmetic derives from just the Peano Axioms [Potter] |
| 10674 | A plural language gives a single comprehensive induction axiom for arithmetic [Hossack] |
| 10681 | In arithmetic singularists need sets as the instantiator of numeric properties [Hossack] |
| 10685 | Set theory is the science of infinity [Hossack] |
| 23621 | Numbers are properties, not sets (because numbers are magnitudes) [Hossack] |
| 23622 | We can only mentally construct potential infinities, but maths needs actual infinities [Hossack] |
| 22310 | The formalist defence against Gödel is to reject his metalinguistic concept of truth [Potter] |
| 22298 | Why is fictional arithmetic applicable to the real world? [Potter] |
| 22287 | If 'concrete' is the negative of 'abstract', that means desires and hallucinations are concrete [Potter] |
| 10668 | We are committed to a 'group' of children, if they are sitting in a circle [Hossack] |
| 13043 | A relation is a set consisting entirely of ordered pairs [Potter] |
| 22284 | 'Greater than', which is the ancestral of 'successor', strictly orders the natural numbers [Potter] |
| 13042 | If dependence is well-founded, with no infinite backward chains, this implies substances [Potter] |
| 10664 | Complex particulars are either masses, or composites, or sets [Hossack] |
| 10678 | The relation of composition is indispensable to the part-whole relation for individuals [Hossack] |
| 13041 | Collections have fixed members, but fusions can be carved in innumerable ways [Potter] |
| 10665 | Leibniz's Law argues against atomism - water is wet, unlike water molecules [Hossack] |
| 10682 | The fusion of five rectangles can decompose into more than five parts that are rectangles [Hossack] |
| 10709 | Priority is a modality, arising from collections and members [Potter] |
| 22281 | A material conditional cannot capture counterfactual reasoning [Potter] |
| 22327 | Knowledge from a drunken schoolteacher is from a reliable and unreliable process [Potter] |
| 10663 | A thought can refer to many things, but only predicate a universal and affirm a state of affairs [Hossack] |
| 22273 | Traditionally there are twelve categories of judgement, in groups of three [Potter] |
| 22290 | The phrase 'the concept "horse"' can't refer to a concept, because it is saturated [Potter] |
| 22283 | Compositionality should rely on the parsing tree, which may contain more than sentence components [Potter] |
| 22282 | 'Direct compositonality' says the components wholly explain a sentence meaning [Potter] |
| 22296 | Compositionality is more welcome in logic than in linguistics (which is more contextual) [Potter] |
| 6005 | Animals are dangerous and nourishing, and can't form contracts of justice [Hermarchus, by Sedley] |
| 10683 | We could ignore space, and just talk of the shape of matter [Hossack] |