65 ideas
11159 | My account shows how the concept works, rather than giving an analysis [Fine,K] |
11157 | Modern philosophy has largely abandoned real definitions, apart from sortals [Fine,K] |
11171 | Defining a term and giving the essence of an object don't just resemble - they are the same [Fine,K] |
13252 | Some truths have true negations [Beall/Restall] |
13247 | A truthmaker is an object which entails a sentence [Beall/Restall] |
17926 | Rejecting double negation elimination undermines reductio proofs [Colyvan] |
13249 | (∀x)(A v B) |- (∀x)A v (∃x)B) is valid in classical logic but invalid intuitionistically [Beall/Restall] |
17925 | Showing a disproof is impossible is not a proof, so don't eliminate double negation [Colyvan] |
13243 | Excluded middle must be true for some situation, not for all situations [Beall/Restall] |
13242 | It's 'relevantly' valid if all those situations make it true [Beall/Restall] |
13246 | Relevant logic does not abandon classical logic [Beall/Restall] |
13245 | Relevant consequence says invalidity is the conclusion not being 'in' the premises [Beall/Restall] |
13254 | A doesn't imply A - that would be circular [Beall/Restall] |
13255 | Relevant logic may reject transitivity [Beall/Restall] |
13250 | Free logic terms aren't existential; classical is non-empty, with referring names [Beall/Restall] |
13235 | Logic studies consequence; logical truths are consequences of everything, or nothing [Beall/Restall] |
13238 | Syllogisms are only logic when they use variables, and not concrete terms [Beall/Restall] |
13234 | The view of logic as knowing a body of truths looks out-of-date [Beall/Restall] |
13232 | Logic studies arguments, not formal languages; this involves interpretations [Beall/Restall] |
13241 | The model theory of classical predicate logic is mathematics [Beall/Restall] |
13253 | There are several different consequence relations [Beall/Restall] |
13240 | A sentence follows from others if they always model it [Beall/Restall] |
17924 | Excluded middle says P or not-P; bivalence says P is either true or false [Colyvan] |
13236 | Logical truth is much more important if mathematics rests on it, as logicism claims [Beall/Restall] |
17929 | Löwenheim proved his result for a first-order sentence, and Skolem generalised it [Colyvan] |
17930 | Axioms are 'categorical' if all of their models are isomorphic [Colyvan] |
13237 | Preface Paradox affirms and denies the conjunction of propositions in the book [Beall/Restall] |
17928 | Ordinal numbers represent order relations [Colyvan] |
17923 | Intuitionists only accept a few safe infinities [Colyvan] |
17941 | Infinitesimals were sometimes zero, and sometimes close to zero [Colyvan] |
17922 | Reducing real numbers to rationals suggested arithmetic as the foundation of maths [Colyvan] |
17936 | Transfinite induction moves from all cases, up to the limit ordinal [Colyvan] |
17940 | Most mathematical proofs are using set theory, but without saying so [Colyvan] |
17931 | Structuralism say only 'up to isomorphism' matters because that is all there is to it [Colyvan] |
17932 | If 'in re' structures relies on the world, does the world contain rich enough structures? [Colyvan] |
11151 | An object is dependent if its essence prevents it from existing without some other object [Fine,K] |
11152 | Essences are either taken as real definitions, or as necessary properties [Fine,K] |
11161 | Essentially having a property is naturally expressed as 'the property it must have to be what it is' [Fine,K] |
11160 | Simple modal essentialism refers to necessary properties of an object [Fine,K] |
11158 | Essentialist claims can be formulated more clearly with quantified modal logic [Fine,K] |
11167 | Metaphysical necessity is a special case of essence, not vice versa [Fine,K] |
16537 | Essence as necessary properties produces a profusion of essential properties [Fine,K, by Lowe] |
11163 | The nature of singleton Socrates has him as a member, but not vice versa [Fine,K] |
11164 | It is not part of the essence of Socrates that a huge array of necessary truths should hold [Fine,K] |
10935 | An essential property of something must be bound up with what it is to be that thing [Fine,K, by Rami] |
10936 | Essential properties are part of an object's 'definition' [Fine,K, by Rami] |
11165 | If Socrates lacks necessary existence, then his nature cannot require his parents' existence [Fine,K] |
13244 | Relevant necessity is always true for some situation (not all situations) [Beall/Restall] |
11166 | The subject of a proposition need not be the source of its necessity [Fine,K] |
11169 | Conceptual necessities rest on the nature of all concepts [Fine,K] |
11162 | Socrates is necessarily distinct from the Eiffel Tower, but that is not part of his essence [Fine,K] |
11168 | Metaphysical necessities are true in virtue of the nature of all objects [Fine,K] |
17943 | Probability supports Bayesianism better as degrees of belief than as ratios of frequencies [Colyvan] |
17939 | Mathematics can reveal structural similarities in diverse systems [Colyvan] |
17938 | Mathematics can show why some surprising events have to occur [Colyvan] |
17934 | Proof by cases (by 'exhaustion') is said to be unexplanatory [Colyvan] |
17933 | Reductio proofs do not seem to be very explanatory [Colyvan] |
17935 | If inductive proofs hold because of the structure of natural numbers, they may explain theorems [Colyvan] |
17942 | Can a proof that no one understands (of the four-colour theorem) really be a proof? [Colyvan] |
17937 | Mathematical generalisation is by extending a system, or by abstracting away from it [Colyvan] |
13239 | Judgement is always predicating a property of a subject [Beall/Restall] |
13248 | We can rest truth-conditions on situations, rather than on possible worlds [Beall/Restall] |
13233 | Propositions commit to content, and not to any way of spelling it out [Beall/Restall] |
11170 | Analytic truth may only be true in virtue of the meanings of certain terms [Fine,K] |
11172 | The meaning of 'bachelor' is irrelevant to the meaning of 'unmarried man' [Fine,K] |