11 ideas
| 13489 | Von Neumann treated cardinals as a special sort of ordinal [Neumann, by Hart,WD] |
| Full Idea: Von Neumann's decision was to start with the ordinals and to treat cardinals as a special sort of ordinal. | |
| From: report of John von Neumann (On the Introduction of Transfinite Numbers [1923]) by William D. Hart - The Evolution of Logic 3 | |
| A reaction: [see Hart 73-74 for an explication of this] |
| 12336 | A von Neumann ordinal is a transitive set with transitive elements [Neumann, by Badiou] |
| Full Idea: In Von Neumann's definition an ordinal is a transitive set in which all of the elements are transitive. | |
| From: report of John von Neumann (On the Introduction of Transfinite Numbers [1923]) by Alain Badiou - Briefings on Existence 11 |
| 18180 | Von Neumann numbers are preferred, because they continue into the transfinite [Maddy on Neumann] |
| Full Idea: Von Neumann's version of the natural numbers is in fact preferred because it carries over directly to the transfinite ordinals. | |
| From: comment on John von Neumann (On the Introduction of Transfinite Numbers [1923]) by Penelope Maddy - Naturalism in Mathematics I.2 n9 |
| 18179 | For Von Neumann the successor of n is n U {n} (rather than {n}) [Neumann, by Maddy] |
| Full Idea: For Von Neumann the successor of n is n U {n} (rather than Zermelo's successor, which is {n}). | |
| From: report of John von Neumann (On the Introduction of Transfinite Numbers [1923]) by Penelope Maddy - Naturalism in Mathematics I.2 n8 |
| 15925 | Each Von Neumann ordinal number is the set of its predecessors [Neumann, by Lavine] |
| Full Idea: Each Von Neumann ordinal number is the set of its predecessors. ...He had shown how to introduce ordinal numbers as sets, making it possible to use them without leaving the domain of sets. | |
| From: report of John von Neumann (On the Introduction of Transfinite Numbers [1923]) by Shaughan Lavine - Understanding the Infinite V.3 |
| 19400 | Possibles demand existence, so as many of them as possible must actually exist [Leibniz] |
| Full Idea: From the conflict of all the possibles demanding existence, this at once follows, that there exists that series of things by which as many of them as possible exist. | |
| From: Gottfried Leibniz (Exigency to Exist in Essences [1690], p.91) | |
| A reaction: I'm in tune with a lot of Leibniz, but my head swims with this one. He seems to be a Lewisian about possible worlds - that they are concrete existing entities (with appetites!). Could Lewis include Leibniz's idea in his system? |
| 19401 | God's sufficient reason for choosing reality is in the fitness or perfection of possibilities [Leibniz] |
| Full Idea: The sufficient reason for God's choice can be found only in the fitness (convenance) or in the degree of perfection that the several worlds possess. | |
| From: Gottfried Leibniz (Exigency to Exist in Essences [1690], p.92) | |
| A reaction: The 'fitness' of a world and its 'perfection' seem very different things. A piece of a jigsaw can have wonderful fitness, without perfection. Occasionally you get that sinking feeling with metaphysicians that they just make it up. |
| 7771 | We need 'events' to explain adverbs, which are adjectival predicates of events [Davidson, by Lycan] |
| Full Idea: To deal with the truth conditions for some adverbs, Davidson introduced a domain of 'events', and made adverbs into adjectival predicates of events. | |
| From: report of Donald Davidson (The Logical Form of Action Sentences [1967]) by William Lycan - Philosophy of Language Ch.9 | |
| A reaction: This seems to be a striking case of a procedure of which I heartily disapprove - deriving you ontology from your semantics. Do all languages have adverbs? |
| 8860 | Language-learning is not good enough evidence for the existence of events [Yablo on Davidson] |
| Full Idea: One needs a better reason for believing in events than the help they provide with language-learning. | |
| From: comment on Donald Davidson (The Logical Form of Action Sentences [1967], §8) by Stephen Yablo - Apriority and Existence §8 | |
| A reaction: I can almost believe in micro-events at the quantum level, but I cannot believe that the Renaissance (made of events within events within events) is an event, even though I may 'quantify over it', and discuss its causes and effects. |
| 15002 | If the best theory of adverbs refers to events, then our ontology should include events [Davidson, by Sider] |
| Full Idea: Davidson argued that the best linguistic theory of adverbial modification assigns truth-conditions quantifying over events; thus we must embrace an ontology of events. | |
| From: report of Donald Davidson (The Logical Form of Action Sentences [1967]) by Theodore Sider - Writing the Book of the World 07.8 | |
| A reaction: Sider is critical and I agree. This is just the sort of linguistic manoeuvre that gets philosophy a bad name. As Yablo remarks, we have a terrible tendency to want to thingify everything. |
| 19402 | The actual universe is the richest composite of what is possible [Leibniz] |
| Full Idea: The actual universe is the collection of the possibles which forms the richest composite. | |
| From: Gottfried Leibniz (Exigency to Exist in Essences [1690], p.92) | |
| A reaction: 'Richest' for Leibniz means a maximum combination of existence, order and variety. It's rather like picking the best starting team from a squad of footballers. |