Path: ...!news.tomockey.net!news.samoylyk.net!news.quux.org!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!eternal-september.org!.POSTED!not-for-mail From: FromTheRafters Newsgroups: sci.math Subject: Re: The reality of sets, on a scale of 1 to 10 [Was: The non-existence of "dark numbers"] Date: Fri, 04 Apr 2025 17:12:27 -0400 Organization: Peripheral Visions Lines: 22 Message-ID: References: <3449b34c60603bf59f694df42857003d0bda7ab5@i2pn2.org> Reply-To: erratic.howard@gmail.com MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-15"; format=flowed Content-Transfer-Encoding: 8bit Injection-Date: Fri, 04 Apr 2025 23:12:35 +0200 (CEST) Injection-Info: dont-email.me; posting-host="a100b5c6d1170e676b7b9b71c8f8f5d9"; logging-data="505038"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1+7JPHmAjgLeZ4lE3Vmr4+aujtNESVh3PQ=" Cancel-Lock: sha1:pXjr4KQYg3CX9LW8SnR3aOhFXQE= X-Newsreader: MesNews/1.08.06.00-gb X-ICQ: 1701145376 Bytes: 2432 WM wrote on 4/4/2025 : > On 04.04.2025 18:41, Alan Mackenzie wrote: >> WM wrote: >>> On 03.04.2025 21:10, Alan Mackenzie wrote: >> >>>>> It is not at all difficult to understand. Difficult to understand is >>>>> only why cardinality is used at all. >> >>>> Those two sentences contradict eachother. Cardinality is used because it >>>> is a sensible way of comparing the size of sets. >> >>> No. >> >> You're wrong. > > You are caught in a world of stupidity. Set theorists have damaged the honour > of human intellect even more than Pope Pius XII. > > When an element is added to a set, then this set is no longer the same but > different because the number of its members is different. How do you know that they are not 'the same'? No bijection perhaps?