Path: csiph.com!newsfeed.hal-mli.net!feeder3.hal-mli.net!newsfeed.hal-mli.net!feeder1.hal-mli.net!newsfeed.xs4all.nl!newsfeed4.news.xs4all.nl!xs4all!post.news.xs4all.nl!not-for-mail Return-Path: X-Original-To: python-list@python.org Delivered-To: python-list@mail.python.org X-Spam-Status: OK 0.017 X-Spam-Evidence: '*H*': 0.97; '*S*': 0.00; 'mathematics': 0.05; '"""': 0.07; 'abstraction': 0.09; 'undefined': 0.09; 'python': 0.11; 'suggest': 0.14; 'distinct': 0.16; 'early.': 0.16; 'informal': 0.16; 'relates': 0.16; 'elements': 0.16; 'sat,': 0.16; 'wrote:': 0.18; 'differ': 0.19; 'feb': 0.22; 'machine': 0.22; 'memory': 0.22; '15,': 0.26; 'define': 0.26; 'header:In-Reply-To:1': 0.27; 'am,': 0.29; 'absolute': 0.30; 'subject:list': 0.30; 'message- id:@mail.gmail.com': 0.30; "i'm": 0.30; 'everyone': 0.33; 'knows': 0.35; 'definition': 0.35; 'objects': 0.35; 'but': 0.35; 'received:google.com': 0.35; 'set.': 0.36; 'surely': 0.36; 'too': 0.37; 'level': 0.37; 'question,': 0.38; 'to:addr:python-list': 0.38; 'little': 0.38; 'to:addr:python.org': 0.39; 'unable': 0.39; 'called': 0.40; 'how': 0.40; 'even': 0.60; 'ian': 0.60; 'simply': 0.61; 'offer': 0.62; 'such': 0.63; 'our': 0.64; 'determine': 0.67; 'gathering': 0.68; 'physical': 0.72 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :content-type; bh=HBqZIQbOpzx9+DKClOajFIbKYUlAj0paHbDsvHUDtBY=; b=MSHt5x2OywUP18tNYLdcAC7Vq9h9iypxiOV+bhB4258JJC9fU8ONUBSvofd14Pk1N1 KN7f08fZgH8LtHa+blWKyoTG783Ypnu/0tnJA7HXgs0parpowRg8JX+3GasAe2XfGJ9C sGQWfrU9KYm8/YaRkYX5U3/7uaI60cfJ1rSxXboWJCH+Wt5ao9PyoASHqwLSFDDGB2Eg XUXygfkFapwprBaP7TUXAAAjuDEDwzMcQrdikTdB4eK/afW+pSygJIt9o/t7nlZntgQ+ xJVtgC31+2p/FQ8yoD7w+tR1pIEbPYtfpKCmZjdC5zNcjIwSOmoh6agxAPEJ0G9Mdb7b nACg== X-Received: by 10.66.141.144 with SMTP id ro16mr16253835pab.131.1392489992737; Sat, 15 Feb 2014 10:46:32 -0800 (PST) MIME-Version: 1.0 In-Reply-To: References: <13208de8-0f85-4e60-b059-dc087c8fda41@googlegroups.com> <917ede6d-db7c-4a8c-8203-27677283776b@googlegroups.com> <871tz5piy0.fsf@elektro.pacujo.net> <87vbwho1i0.fsf@elektro.pacujo.net> <87mwhtnzdu.fsf@elektro.pacujo.net> <87y51cn2m9.fsf@elektro.pacujo.net> <87mwhsn0nx.fsf@elektro.pacujo.net> <52ff4ce4$0$29973$c3e8da3$5496439d@news.astraweb.com> <87iosgmveg.fsf@elektro.pacujo.net> <52ff7cac$0$29973$c3e8da3$5496439d@news.astraweb.com> <87wqgwl4oo.fsf@elektro.pacujo.net> From: Ian Kelly Date: Sat, 15 Feb 2014 11:45:52 -0700 Subject: Re: Explanation of list reference To: Python Content-Type: text/plain; charset=ISO-8859-1 X-BeenThere: python-list@python.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: General discussion list for the Python programming language List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Newsgroups: comp.lang.python Message-ID: Lines: 26 NNTP-Posting-Host: 2001:888:2000:d::a6 X-Trace: 1392489996 news.xs4all.nl 2924 [2001:888:2000:d::a6]:46373 X-Complaints-To: abuse@xs4all.nl Xref: csiph.com comp.lang.python:66470 On Sat, Feb 15, 2014 at 11:37 AM, Ian Kelly wrote: > But what is a set? Cantor offers this definition: > > """ > A set is a gathering together into a whole of definite, distinct > objects of our perception [Anschauung] or of our thought - which are > called elements of the set. > """ > > But what precisely are "objects" and how are we to determine their > distinctness? Cantor above relates them to perception or thought, but > surely my own perception and thought differ from Cantor's. If > mathematics or philosophy offer us any absolute answer to this > question, I'm unable to find it. I sent the last message a little too early. To continue: the above definition of set is an informal one. In axiomatic set theory, it turns out that "set" is simply taken as an undefined primitive. In other words: "Set?! We all know what's a set! Everyone knows what's a set!!" At some level we have to have primitives, and while we can at some level delve into the machine in order to define an object in terms of memory location and layout and lifetime and even physical considerations such as "which memory?"; at the level of the Python abstraction I suggest that an object is simply an undefined primitive.