display all the ideas for this combination of texts
4 ideas
10573 | Dedekind cuts lead to the bizarre idea that there are many different number 1's [Fine,K] |
Full Idea: Because of Dedekind's definition of reals by cuts, there is a bizarre modern doctrine that there are many 1's - the natural number 1, the rational number 1, the real number 1, and even the complex number 1. | |
From: Kit Fine (Replies on 'Limits of Abstraction' [2005], 2) | |
A reaction: See Idea 10572. |
10575 | Why should a Dedekind cut correspond to a number? [Fine,K] |
Full Idea: By what right can Dedekind suppose that there is a number corresponding to any pair of irrationals that constitute an irrational cut? | |
From: Kit Fine (Replies on 'Limits of Abstraction' [2005], 2) |
10574 | Unless we know whether 0 is identical with the null set, we create confusions [Fine,K] |
Full Idea: What is the union of the singleton {0}, of zero, and the singleton {φ}, of the null set? Is it the one-element set {0}, or the two-element set {0, φ}? Unless the question of identity between 0 and φ is resolved, we cannot say. | |
From: Kit Fine (Replies on 'Limits of Abstraction' [2005], 2) |
17890 | There are at least eleven types of large cardinal, of increasing logical strength [Koellner] |
Full Idea: Some of the standard large cardinals (in order of increasing (logical) strength) are: inaccessible, Mahlo, weakly compact, indescribable, Erdös, measurable, strong, Wodin, supercompact, huge etc. (...and ineffable). | |
From: Peter Koellner (On the Question of Absolute Undecidability [2006], 1.4) | |
A reaction: [I don't understand how cardinals can have 'logical strength', but I pass it on anyway] |