78 ideas
8187 | Frege was strongly in favour of taking truth to attach to propositions [Frege, by Dummett] |
10073 | There cannot be a set theory which is complete [Smith,P] |
10616 | Second-order arithmetic can prove new sentences of first-order [Smith,P] |
10076 | The 'range' of a function is the set of elements in the output set created by the function [Smith,P] |
10605 | Two functions are the same if they have the same extension [Smith,P] |
10075 | A 'partial function' maps only some elements to another set [Smith,P] |
10074 | A 'total function' maps every element to one element in another set [Smith,P] |
10612 | An argument is a 'fixed point' for a function if it is mapped back to itself [Smith,P] |
10615 | The Comprehension Schema says there is a property only had by things satisfying a condition [Smith,P] |
10595 | A 'theorem' of a theory is a sentence derived from the axioms using the proof system [Smith,P] |
18772 | We can treat designation by a few words as a proper name [Frege] |
14075 | Proper name in modal contexts refer obliquely, to their usual sense [Frege, by Gibbard] |
10424 | A Fregean proper name has a sense determining an object, instead of a concept [Frege, by Sainsbury] |
18773 | People may have different senses for 'Aristotle', like 'pupil of Plato' or 'teacher of Alexander' [Frege] |
4978 | The meaning of a proper name is the designated object [Frege] |
10510 | Frege ascribes reference to incomplete expressions, as well as to singular terms [Frege, by Hale] |
18937 | If sentences have a 'sense', empty name sentences can be understood that way [Frege, by Sawyer] |
18940 | It is a weakness of natural languages to contain non-denoting names [Frege] |
18939 | In a logically perfect language every well-formed proper name designates an object [Frege] |
10602 | A 'natural deduction system' has no axioms but many rules [Smith,P] |
10613 | No nice theory can define truth for its own language [Smith,P] |
9462 | Frege is intensionalist about reference, as it is determined by sense; identity of objects comes first [Frege, by Jacquette] |
18936 | Frege moved from extensional to intensional semantics when he added the idea of 'sense' [Frege, by Sawyer] |
10078 | An 'injective' ('one-to-one') function creates a distinct output element from each original [Smith,P] |
10077 | A 'surjective' ('onto') function creates every element of the output set [Smith,P] |
10079 | A 'bijective' function has one-to-one correspondence in both directions [Smith,P] |
10070 | If everything that a theory proves is true, then it is 'sound' [Smith,P] |
10086 | Soundness is true axioms and a truth-preserving proof system [Smith,P] |
10596 | A theory is 'sound' iff every theorem is true (usually from true axioms and truth-preservation) [Smith,P] |
10598 | A theory is 'negation complete' if it proves all sentences or their negation [Smith,P] |
10597 | 'Complete' applies both to whole logics, and to theories within them [Smith,P] |
10069 | A theory is 'negation complete' if one of its sentences or its negation can always be proved [Smith,P] |
10609 | Two routes to Incompleteness: semantics of sound/expressible, or syntax of consistency/proof [Smith,P] |
10080 | 'Effective' means simple, unintuitive, independent, controlled, dumb, and terminating [Smith,P] |
10087 | A theory is 'decidable' if all of its sentences could be mechanically proved [Smith,P] |
10088 | Any consistent, axiomatized, negation-complete formal theory is decidable [Smith,P] |
10081 | A set is 'enumerable' is all of its elements can result from a natural number function [Smith,P] |
10083 | A set is 'effectively enumerable' if a computer could eventually list every member [Smith,P] |
10084 | A finite set of finitely specifiable objects is always effectively enumerable (e.g. primes) [Smith,P] |
10085 | The set of ordered pairs of natural numbers <i,j> is effectively enumerable [Smith,P] |
10601 | The thorems of a nice arithmetic can be enumerated, but not the truths (so they're diffferent) [Smith,P] |
10600 | Being 'expressible' depends on language; being 'capture/represented' depends on axioms and proof system [Smith,P] |
10599 | For primes we write (x not= 1 ∧ ∀u∀v(u x v = x → (u = 1 ∨ v = 1))) [Smith,P] |
10610 | The reals contain the naturals, but the theory of reals doesn't contain the theory of naturals [Smith,P] |
10619 | The truths of arithmetic are just true equations and their universally quantified versions [Smith,P] |
10608 | The number of Fs is the 'successor' of the Gs if there is a single F that isn't G [Smith,P] |
10618 | All numbers are related to zero by the ancestral of the successor relation [Smith,P] |
10849 | Baby arithmetic covers addition and multiplication, but no general facts about numbers [Smith,P] |
10850 | Baby Arithmetic is complete, but not very expressive [Smith,P] |
10852 | Robinson Arithmetic (Q) is not negation complete [Smith,P] |
10851 | Robinson Arithmetic 'Q' has basic axioms, quantifiers and first-order logic [Smith,P] |
10068 | Natural numbers have zero, unique successors, unending, no circling back, and no strays [Smith,P] |
10603 | The logic of arithmetic must quantify over properties of numbers to handle induction [Smith,P] |
10848 | Multiplication only generates incompleteness if combined with addition and successor [Smith,P] |
10604 | Incompleteness results in arithmetic from combining addition and successor with multiplication [Smith,P] |
10617 | The 'ancestral' of a relation is a new relation which creates a long chain of the original relation [Smith,P] |
10533 | We can't get a semantics from nouns and predicates referring to the same thing [Frege, by Dummett] |
4893 | Frege was asking how identities could be informative [Frege, by Perry] |
18752 | 'The concept "horse"' denotes a concept, yet seems also to denote an object [Frege, by McGee] |
22318 | Frege failed to show when two sets of truth-conditions are equivalent [Frege, by Potter] |
4980 | The meaning (reference) of a sentence is its truth value - the circumstance of it being true or false [Frege] |
9180 | Holism says all language use is also a change in the rules of language [Frege, by Dummett] |
4981 | The reference of a word should be understood as part of the reference of the sentence [Frege] |
15597 | Frege's Puzzle: from different semantics we infer different reference for two names with the same reference [Frege, by Fine,K] |
17002 | Frege's 'sense' is ambiguous, between the meaning of a designator, and how it fixes reference [Kripke on Frege] |
18778 | Every descriptive name has a sense, but may not have a reference [Frege] |
7805 | Frege started as anti-realist, but the sense/reference distinction led him to realism [Frege, by Benardete,JA] |
4976 | The meaning (reference) of 'evening star' is the same as that of 'morning star', but not the sense [Frege] |
4977 | In maths, there are phrases with a clear sense, but no actual reference [Frege] |
4979 | We are driven from sense to reference by our desire for truth [Frege] |
15155 | Expressions always give ways of thinking of referents, rather than the referents themselves [Frege, by Soames] |
11126 | 'Sense' gives meaning to non-referring names, and to two expressions for one referent [Frege, by Margolis/Laurence] |
8164 | Frege was the first to construct a plausible theory of meaning [Frege, by Dummett] |
9817 | Earlier Frege focuses on content itself; later he became interested in understanding content [Frege, by Dummett] |
8171 | Frege divided the meaning of a sentence into sense, force and tone [Frege, by Dummett] |
4954 | Frege uses 'sense' to mean both a designator's meaning, and the way its reference is determined [Kripke on Frege] |
7304 | Frege explained meaning as sense, semantic value, reference, force and tone [Frege, by Miller,A] |
1863 | If the soul achieves well-being in another life, it doesn't follow that I do [Aquinas] |