- From: Pat Hayes <phayes@ihmc.us>
- Date: Mon, 11 Jan 2010 21:43:02 -0600
- To: Martin J. Dürst <duerst@it.aoyama.ac.jp>
- Cc: Dan Connolly <connolly@w3.org>, "www-tag@w3.org" <www-tag@w3.org>
On Jan 11, 2010, at 7:34 PM, Martin J. Dürst wrote: > Hello Pat, > > I'm not sure if you misunderstood me, but I didn't really want to > claim that numbers don't exist. I mainly wanted to point out, with a > hopefully much clearer example, that the argument about whether > resources exist or not (which Ian brought up) isn't really helpful > in deciding whether the term should be used or not. Ah, then we entirely agree. Sorry if my philosophical feathers got prematurely ruffled. > > So what I'm saying is "Even if you [take a nominalistic viewpoint > and] claim that numbers don't 'exist', this doesn't mean that it > doesn't make sense to talk about numbers. So even if you claim that > resources don't 'exist', this doesn't mean that it doesn't make > sense to talk about resources." > > Regards, Martin. > > P.S.: I haven't done philosophy of mathematics, so I have never > thought about this too deeply, but if I had to, I'd probably > strongly tend towards thinking that numbers DO exist. It really is VERY hard work being a nominalist mathematician :-) Pat > > On 2010/01/12 0:42, Pat Hayes wrote: >> >> On Jan 11, 2010, at 1:30 AM, Martin J. Dürst wrote: >> >>> Hello Dan, dear TAG, >>> >>> On 2009/12/10 13:55, Dan Connolly wrote: >>>> The clock has started on this issue in the HTML WG; proposals are >>>> due >>>> January 16, 2010 >>>> http://lists.w3.org/Archives/Public/public-html/2009Dec/0256.html >>>> >>>> I'm thinking out loud a bit here... >>>> >>>> I'm sympathetic to this viewpoint: >>>> >>>> "the confusion is caused by trying to reference something that >>>> doesn't >>>> exist. There is no such thing as what you call a "resource" -- >>>> it's an >>>> abstract concept that has no correspondance to the real world. It >>>> is >>>> unnecessary and makes talking about our infrastructure more >>>> complicated." >>>> -- http://lists.w3.org/Archives/Public/public-html/2009Sep/ >>>> 1133.html >>> >>> I was reading this a few weeks ago, and didn't feel comfortable >>> with it. >>> Recently, I think I found a way to explain why. Consider the >>> following >>> text: >>> >>> "the confusion is caused by trying to reference something that >>> doesn't >>> exist. There is no such thing as what you call a "number" -- it's an >>> abstract concept that has no correspondence to the real world." >>> >>> Indeed numbers don't exist in the real world. I can have five >>> oranges >>> or five apples, or hold up five fingers, but "five", what's that? >>> Can >>> you show me "five"? No. It will always be "five something". >> >> Martin, you really should not be trying to do philosophy of >> mathematics >> in a forum like this. The point of view you are (very loosely) >> expounding here is called 'nominalism'. It is one point of view, >> but by >> no means obvious or widely accepted. In my own view, like that of >> most >> working mathematicians, numbers *do* exist. I cannot SHOW you five, >> of >> course, because it is not physical; nevertheless, it does exist. (I >> would say, OF COURSE numbers exist in the real world. If they did >> not, >> equations would have no solution - because to have a solution >> means, a >> solution (which is a number assignment to the variables of the >> equation) >> *exists* - but they do; ergo, numbers exist.) And numbers can >> certainly >> be referred to. In fact, IMO - admittedly more controversial - >> nonexistent things can be referred to: you know who I mean by the >> name >> "Sherlock Holmes", for example. >> >> The problem with nominalism, by the way, is similar to that of >> atmospheric corrosion: it is very hard to stop it, once you start >> it up. >> Numbers don't exist in the real world... so, do programs exist? After >> all, a program file is just a binary file, which is nothing but a >> sequence of bits. Isn't the program itself just an imaginary >> abstraction? And what about those 'bits', aren't they *really*, in >> the >> *real* world, just electrical patterns in very small circuits? All >> you >> have argued here, in fact, is that there is a level of abstraction >> from >> the ultimate physical reality that you happen to be personally >> comfortable with (roughly, system-level programming, involving >> files and >> addresses), and you have decided is 'real'; anything above that is >> not >> 'real' for you. But your choice of 'real' is just as arbitrary as >> everyone else's. By my lights, your reality is way down in the weeds. >> When I read a web page, I am thinking about the weather in Oaxcala, >> not >> about files and addresses. >> >> Pat Hayes >> >> >>> >>> Nevertheless, I guess most people agree that "five", and numbers in >>> general, are immensely useful, even if they don't exist in the real >>> world. >>> >>> >>>> Meanwhile, the translation impact suggests otherwise: >>>> http://lists.w3.org/Archives/Public/public-html/2009Sep/1136.html >>> >>> That talks about the issue of translating the term "resource". >>> >>> There's also the issue of language negotiation. >>> http://httpd.apache.org/docs/2.2/, for example, looks different >>> for me >>> in Opera (where the top language in Accept-Language is English) >>> and in >>> Safari (where it's Japanese). Yet it's the same URI, and the same >>> resource (the top page of Apache HTTP Server Version 2.2 >>> documentation). >>> >>>> Ian points out usage that suggests "a resource is a bag of bits" >>>> in HTML 4, CSS, SVG etc. >>>> http://lists.w3.org/Archives/Public/public-html/2009Sep/1132.html >>>> >>>> Roy Fielding dismisses those as "just examples," but I think it's >>>> a bit more subtle than that... I think the webarch view of those >>>> usages >>>> is that typically, a URI identifies >>>> pretty much a file... the kind whose contents change over time, >>>> not the >>>> contents of the file at any one time. So to say '<xyz.html> >>>> identifies >>>> an HTML file' is not to say that it identifies a bag/sequence of >>>> bits, >>>> but rather that it identifies a resource whose representations >>>> have mime >>>> type text/html . >>>> But as I say, I'm sympathetic to the position that (outside of the >>>> Semantic Web) this >>>> abstraction just makes talking about all this stuff more >>>> complicated. >>>> >>>> Meanwhile, Ian also says: >>>> >>>> This is actually intended to refer to "bag of bits". It >>>> identifies a >>>> bag of bits in the same way that a telephone number identifies a >>>> person. Sure, if you call a number at different times you might >>>> end up >>>> with different people, but you're still using a phone number to >>>> identify a person, you just don't know which one until you try to >>>> use >>>> the phone. >>> >>> Well, that's true in some cases (where you use the phone number to >>> "identify" several people living there), but in many cases, it's >>> actually not true. There's definitely the very frequent case that >>> you >>> have a phone number identifying (for yourself) a single person, but >>> where you're not sure you'll get him/her, or somebody else from the >>> family (who exactly you don't really care). There's also the case >>> that >>> the phone gets answered by a (to you) complete stranger or somebody >>> you wouldn't expect (and therefore wouldn't identify by that phone >>> number) because that (to you) complete stranger happened to visit >>> and >>> e.g. was asked to pick up the phone and tell you that the phone's >>> owner is just washing the dishes or whatever, and will call back >>> soon. >>> >>>> I find that usage of "identify" very unappealing. I think normal >>>> usage >>>> of "identify" >>>> is unambiguous. If I say "In this game, teams are identified by >>>> color" and >>>> then told you that blue identifies team X and a different team Y, >>>> you'd >>>> consider that nonsense. >>> >>> Yes indeed. >>> >>> Regards, Martin. >>> >>>> I wonder about some terminology that just relates URIs with byte >>>> sequences, >>>> without going thru the intermediate concept of resources, and yet >>>> doesn't >>>> use "identify" in this confusing sense. >>>> >>>> Something like: >>>> >>>> A URL is a key typically used to retrieve a page from the Web; more >>>> generally, >>>> it is used as an address in the Web, whether to find documents, >>>> mailboxes, >>>> services, applications, etc. >>>> >>>> "navigation marker" also appeals to me, though I'm not sure >>>> there's any >>>> specific place >>>> in the HTML 5 spec to talk about it that way. >>>> >>>> So "find" in place of "identifiy". Somewhat ironic... "find" is a >>>> synonym for "locate"... >>>> so maybe... >>>> >>>> A URL is a key, typically used to locate a Web page; more >>>> generally, >>>> it is >>>> used to locate mailboxes, services, applications, etc. >>>> >>>> (footnote: I try to tow the party line where the standard term is >>>> 'URI' >>>> rather than 'URL', >>>> but only out of duty/burden/obligation; somewhere between RFC2396 >>>> in '98 >>>> and 3986 in '05, I tried to convince TimBL and the TAG that it's >>>> pushing >>>> water uphill to try >>>> to get the community to learn 'URI' rather than just going with >>>> the flow >>>> and using 'URL', >>>> but I couldn't make the sale. I'm reasonably happy to see >>>> arguments on >>>> both sides examined >>>> in some detail in the context of working out IRI interop stuff.) >>>> >>>> But maybe not... I think the analogy with files suggests that >>>> 'locate' >>>> raises >>>> the same issues as 'identify'; that is: filenames name files... or >>>> identify files... or >>>> locate files; in any case, when you open a file, edit it, and >>>> save it >>>> back, it's >>>> still the same file, and the filename identifies/names/locates/ >>>> refers to >>>> the file, >>>> not its contents at a given time. This analogy works with >>>> variables in a >>>> program, too: >>>> >>>> x = 1 >>>> y = 2 >>>> x = y + 2 >>>> >>>> There's just one variable called/named x; the name 'x' doesn't >>>> refer to >>>> 1 nor to 3, but rather to >>>> the place in memory that holds 1 at first and then 3. >>>> >>>> I guess it's only in very informal glosses that you can skip from >>>> the >>>> URL to the sequence-of-bytes >>>> without referring to the notion in between... though 'retrieve' >>>> does >>>> seem to get around it. >>>> Filenames can be used to retrieve sequences of bytes... variable >>>> names >>>> can be used >>>> to retrieve values. 'retrieve' doesn't generalize to mailto: and >>>> POST so >>>> well, but as Ian >>>> pointed out somewhere in the thread, the HTML 5 spec doesn't need >>>> that >>>> generalization. >>>> >>>> One specific case that the terminology showed up in the HTML 5 >>>> spec was >>>> around >>>> caches, I think; in that case, it's clear to me that the simplest >>>> way to >>>> talk about >>>> it is to talk about caching responses... or the content of response >>>> messages. >>>> Something like that. >>>> >>>> I hope to look at a few specific cases of HTML 5 spec text, but >>>> it's >>>> late here and >>>> I already spent a lot more time on this message than I intended >>>> to... >>>> >>> >>> -- >>> #-# Martin J. Dürst, Professor, Aoyama Gakuin University >>> #-# http://www.sw.it.aoyama.ac.jp mailto:duerst@it.aoyama.ac.jp >>> >>> >> >> ------------------------------------------------------------ >> IHMC (850)434 8903 or (650)494 3973 >> 40 South Alcaniz St. (850)202 4416 office >> Pensacola (850)202 4440 fax >> FL 32502 (850)291 0667 mobile >> phayesAT-SIGNihmc.us http://www.ihmc.us/users/phayes >> >> >> >> >> >> >> > > -- > #-# Martin J. Dürst, Professor, Aoyama Gakuin University > #-# http://www.sw.it.aoyama.ac.jp mailto:duerst@it.aoyama.ac.jp > ------------------------------------------------------------ IHMC (850)434 8903 or (650)494 3973 40 South Alcaniz St. (850)202 4416 office Pensacola (850)202 4440 fax FL 32502 (850)291 0667 mobile phayesAT-SIGNihmc.us http://www.ihmc.us/users/phayes
Received on Tuesday, 12 January 2010 03:44:10 UTC