Path: ...!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!eternal-september.org!.POSTED!not-for-mail From: WM Newsgroups: sci.math Subject: Re: The reality of sets, on a scale of 1 to 10 [Was: The non-existence of "dark numbers"] Date: Sat, 5 Apr 2025 22:51:32 +0200 Organization: A noiseless patient Spider Lines: 23 Message-ID: References: <3449b34c60603bf59f694df42857003d0bda7ab5@i2pn2.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Injection-Date: Sat, 05 Apr 2025 22:51:32 +0200 (CEST) Injection-Info: dont-email.me; posting-host="5b0c37c41340495d601ca7bcde546cc5"; logging-data="3369984"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX18HiiDwdt5k/ayZUSiBf7T+iFMrMaSseYY=" User-Agent: Mozilla Thunderbird Cancel-Lock: sha1:eICuuY2v7e0PzciRdJcpknIz6wI= Content-Language: en-US In-Reply-To: Bytes: 2550 On 05.04.2025 21:08, FromTheRafters wrote: > WM was thinking very hard : >> On 04.04.2025 23:12, FromTheRafters wrote: >>> WM wrote on 4/4/2025 : >> >>>> 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'? >> >> A set containing element x is not the same as a set not containing >> element x. > > Then of course they are not "the same" but are they equivalent in size? According to Cantor they are equivalent or have same cardinality. But that is not a useful notion *because* sets with different number of members are called equivalent. Regards, WM