60 ideas
22289 | Dedekind proved definition by recursion, and thus proved the basic laws of arithmetic [Dedekind, by Potter] |
9456 | Modal logic is multiple systems, shown in the variety of accessibility relations between worlds [Jacquette] |
7689 | The modal logic of C.I.Lewis was only interpreted by Kripke and Hintikka in the 1960s [Jacquette] |
10183 | An infinite set maps into its own proper subset [Dedekind, by Reck/Price] |
22288 | We have the idea of self, and an idea of that idea, and so on, so infinite ideas are available [Dedekind, by Potter] |
10706 | Dedekind originally thought more in terms of mereology than of sets [Dedekind, by Potter] |
9457 | The two main views in philosophy of logic are extensionalism and intensionalism [Jacquette] |
7681 | Logic describes inferences between sentences expressing possible properties of objects [Jacquette] |
9463 | Classical logic is bivalent, has excluded middle, and only quantifies over existent objects [Jacquette] |
7682 | Logic is not just about signs, because it relates to states of affairs, objects, properties and truth-values [Jacquette] |
7697 | On Russell's analysis, the sentence "The winged horse has wings" comes out as false [Jacquette] |
9466 | Nominalists like substitutional quantification to avoid the metaphysics of objects [Jacquette] |
9465 | Substitutional universal quantification retains truth for substitution of terms of the same type [Jacquette] |
9458 | Extensionalists say that quantifiers presuppose the existence of their objects [Jacquette] |
9461 | Intensionalists say meaning is determined by the possession of properties [Jacquette] |
7701 | Can a Barber shave all and only those persons who do not shave themselves? [Jacquette] |
9823 | Numbers are free creations of the human mind, to understand differences [Dedekind] |
10090 | Dedekind defined the integers, rationals and reals in terms of just the natural numbers [Dedekind, by George/Velleman] |
7524 | Order, not quantity, is central to defining numbers [Dedekind, by Monk] |
17452 | Ordinals can define cardinals, as the smallest ordinal that maps the set [Dedekind, by Heck] |
14131 | Dedekind's ordinals are just members of any progression whatever [Dedekind, by Russell] |
17611 | We want the essence of continuity, by showing its origin in arithmetic [Dedekind] |
10572 | A cut between rational numbers creates and defines an irrational number [Dedekind] |
14437 | Dedekind's axiom that his Cut must be filled has the advantages of theft over honest toil [Dedekind, by Russell] |
18094 | Dedekind says each cut matches a real; logicists say the cuts are the reals [Dedekind, by Bostock] |
18244 | I say the irrational is not the cut itself, but a new creation which corresponds to the cut [Dedekind] |
9824 | In counting we see the human ability to relate, correspond and represent [Dedekind] |
17612 | Arithmetic is just the consequence of counting, which is the successor operation [Dedekind] |
9826 | A system S is said to be infinite when it is similar to a proper part of itself [Dedekind] |
18087 | If x changes by less and less, it must approach a limit [Dedekind] |
13508 | Dedekind gives a base number which isn't a successor, then adds successors and induction [Dedekind, by Hart,WD] |
18096 | Zero is a member, and all successors; numbers are the intersection of sets satisfying this [Dedekind, by Bostock] |
18841 | Categoricity implies that Dedekind has characterised the numbers, because it has one domain [Rumfitt on Dedekind] |
14130 | Induction is proved in Dedekind, an axiom in Peano; the latter seems simpler and clearer [Dedekind, by Russell] |
8924 | Dedekind originated the structuralist conception of mathematics [Dedekind, by MacBride] |
9153 | Dedekindian abstraction talks of 'positions', where Cantorian abstraction talks of similar objects [Dedekind, by Fine,K] |
7707 | To grasp being, we must say why something exists, and why there is one world [Jacquette] |
7687 | Existence is completeness and consistency [Jacquette] |
7692 | Being is maximal consistency [Jacquette] |
7679 | Ontology is the same as the conceptual foundations of logic [Jacquette] |
7678 | Ontology must include the minimum requirements for our semantics [Jacquette] |
7683 | Logic is based either on separate objects and properties, or objects as combinations of properties [Jacquette] |
7684 | Reduce states-of-affairs to object-property combinations, and possible worlds to states-of-affairs [Jacquette] |
7703 | If classes can't be eliminated, and they are property combinations, then properties (universals) can't be either [Jacquette] |
7685 | An object is a predication subject, distinguished by a distinctive combination of properties [Jacquette] |
7699 | Numbers, sets and propositions are abstract particulars; properties, qualities and relations are universals [Jacquette] |
9825 | A thing is completely determined by all that can be thought concerning it [Dedekind] |
12887 | A whole must have one characteristic, an internal relation, and a structure [Rescher/Oppenheim] |
7691 | The actual world is a consistent combination of states, made of consistent property combinations [Jacquette] |
7688 | The actual world is a maximally consistent combination of actual states of affairs [Jacquette] |
7695 | Do proposition-structures not associated with the actual world deserve to be called worlds? [Jacquette] |
7694 | We must experience the 'actual' world, which is defined by maximally consistent propositions [Jacquette] |
7706 | If qualia supervene on intentional states, then intentional states are explanatorily fundamental [Jacquette] |
7704 | Reduction of intentionality involving nonexistent objects is impossible, as reduction must be to what is actual [Jacquette] |
9189 | Dedekind said numbers were abstracted from systems of objects, leaving only their position [Dedekind, by Dummett] |
9827 | We derive the natural numbers, by neglecting everything of a system except distinctness and order [Dedekind] |
9979 | Dedekind has a conception of abstraction which is not psychologistic [Dedekind, by Tait] |
9460 | Extensionalist semantics forbids reference to nonexistent objects [Jacquette] |
9459 | Extensionalist semantics is circular, as we must know the extension before assessing 'Fa' [Jacquette] |
7702 | The extreme views on propositions are Frege's Platonism and Quine's extreme nominalism [Jacquette] |