48 ideas
12330 | In ontology, logic dominated language, until logic was mathematized [Badiou] |
12318 | The female body, when taken in its entirety, is the Phallus itself [Badiou] |
12325 | Philosophy has been relieved of physics, cosmology, politics, and now must give up ontology [Badiou] |
12324 | Consensus is the enemy of thought [Badiou] |
13838 | A decent modern definition should always imply a semantics [Hacking] |
18806 | Frege thought traditional categories had psychological and linguistic impurities [Frege, by Rumfitt] |
13833 | 'Thinning' ('dilution') is the key difference between deduction (which allows it) and induction [Hacking] |
13834 | Gentzen's Cut Rule (or transitivity of deduction) is 'If A |- B and B |- C, then A |- C' [Hacking] |
13835 | Only Cut reduces complexity, so logic is constructive without it, and it can be dispensed with [Hacking] |
12337 | There is 'transivity' iff membership ∈ also means inclusion ⊆ [Badiou] |
12321 | The axiom of choice must accept an indeterminate, indefinable, unconstructible set [Badiou] |
12342 | Topos theory explains the plurality of possible logics [Badiou] |
13845 | The various logics are abstractions made from terms like 'if...then' in English [Hacking] |
13840 | First-order logic is the strongest complete compact theory with Löwenheim-Skolem [Hacking] |
13844 | A limitation of first-order logic is that it cannot handle branching quantifiers [Hacking] |
13842 | Second-order completeness seems to need intensional entities and possible worlds [Hacking] |
12341 | Logic is a mathematical account of a universe of relations [Badiou] |
13837 | With a pure notion of truth and consequence, the meanings of connectives are fixed syntactically [Hacking] |
13839 | Perhaps variables could be dispensed with, by arrows joining places in the scope of quantifiers [Hacking] |
8490 | First-level functions have objects as arguments; second-level functions take functions as arguments [Frege] |
8492 | Relations are functions with two arguments [Frege] |
13843 | If it is a logic, the Löwenheim-Skolem theorem holds for it [Hacking] |
12334 | There is no single unified definition of number [Badiou] |
12335 | Numbers are for measuring and for calculating (and the two must be consistent) [Badiou] |
12333 | Each type of number has its own characteristic procedure of introduction [Badiou] |
12322 | Must we accept numbers as existing when they no longer consist of units? [Badiou] |
12327 | The undecidability of the Continuum Hypothesis may have ruined or fragmented set theory [Badiou] |
12329 | If mathematics is a logic of the possible, then questions of existence are not intrinsic to it [Badiou] |
12328 | Platonists like axioms and decisions, Aristotelians like definitions, possibilities and logic [Badiou] |
8487 | Arithmetic is a development of logic, so arithmetical symbolism must expand into logical symbolism [Frege] |
12331 | Logic is definitional, but real mathematics is axiomatic [Badiou] |
12340 | There is no Being as a whole, because there is no set of all sets [Badiou] |
12323 | Existence is Being itself, but only as our thought decides it [Badiou] |
12326 | The primitive name of Being is the empty set; in a sense, only the empty set 'is' [Badiou] |
12332 | The modern view of Being comes when we reject numbers as merely successions of One [Badiou] |
18899 | Frege takes the existence of horses to be part of their concept [Frege, by Sommers] |
12320 | Ontology is (and always has been) Cantorian mathematics [Badiou] |
4028 | Frege allows either too few properties (as extensions) or too many (as predicates) [Mellor/Oliver on Frege] |
8489 | The concept 'object' is too simple for analysis; unlike a function, it is an expression with no empty place [Frege] |
9947 | Concepts are the ontological counterparts of predicative expressions [Frege, by George/Velleman] |
10319 | An assertion about the concept 'horse' must indirectly speak of an object [Frege, by Hale] |
8488 | A concept is a function whose value is always a truth-value [Frege] |
9948 | Unlike objects, concepts are inherently incomplete [Frege, by George/Velleman] |
4972 | I may regard a thought about Phosphorus as true, and the same thought about Hesperus as false [Frege] |
12338 | We must either assert or deny any single predicate of any single subject [Badiou] |
12316 | For Enlightenment philosophers, God was no longer involved in politics [Badiou] |
8491 | The Ontological Argument fallaciously treats existence as a first-level concept [Frege] |
12317 | The God of religion results from an encounter, not from a proof [Badiou] |