{"id":156,"date":"2003-08-18T15:28:00","date_gmt":"2003-08-18T19:28:00","guid":{"rendered":"http:\/\/www.markbaker.ca\/wp\/?p=157"},"modified":"2003-08-18T15:28:00","modified_gmt":"2003-08-18T19:28:00","slug":"self-description-redux","status":"publish","type":"post","link":"http:\/\/www.markbaker.ca\/blog\/2003\/08\/self-description-redux\/","title":{"rendered":"Self-description, redux"},"content":{"rendered":"<p>Kudos to Kendall Clark for stating\n<a href=\"http:\/\/www.xml.com\/pub\/a\/2003\/08\/13\/deviant.html\">XML is Not Self-Describing<\/a>,\nas <a href=\"http:\/\/www.markbaker.ca\/2002\/09\/Blog\/2003\/07\/16#2003-07-self-describing\">I did last month<\/a>.<\/p>\n\n<p>He writes;<\/p>\n\n<blockquote>\nWell, I&#8217;ve read too much Wittgenstein (not to mention too much Aquinas, Meister Eckhart, and Julian of Norwich) to think that a name is necessarily a self-description\n<\/blockquote>\n\n<p>I haven&#8217;t read them at all (8-), but I think I have a pretty good\nunderstanding of self-description that I developed &#8220;Bottom up&#8221;\nduring my study of Web architecture over the past few years.  As\nKendall brought this up again, I&#8217;d thought I&#8217;d write a few more words\nabout it.<\/p>\n\n<p>As I see it, description is always with respect to some context.  For example,\n&#8220;The sky is blue&#8221; is not a self-descriptive statement unless you know;<\/p>\n\n<ul>\n<li>ASCII<\/li>\n<li>English<\/li>\n<li>Which sky I mean<\/li>\n<li>Which colour blue I mean<\/li>\n<\/ul>\n\n<p>For any bag-o-bits, it seems to me that there exists a finite amount of\ncontextual knowledge which is necessary in order to be able to understand\nit.  &#8220;Self-describing&#8221; then, should mean that the bag itself contains\nsufficient information to identify the required contextual knowledge.<\/p>\n\n<p>Tim Berners-Lee likes to talk a lot about this.  Last\nyear in Honolulu at <a href=\"http:\/\/www2002.org\">WWW2002<\/a>, his keynote was\n<a href=\"http:\/\/www.w3.org\/2002\/Talks\/www2002-tbl\/Overview.html\">Specs Count<\/a>,\nand much of it was about the value in the ability to be able to\nperform successive application of public specifications in order to\nunderstand a message.  <em>That&#8217;s<\/em> contextual knowledge, and as you can see\nin his talk, it doesn&#8217;t begin with the HTTP message, it goes all the way\ndown to the IP segment and Ethernet frame; even those bits must be considered\n(see\n<a href=\"http:\/\/lists.w3.org\/Archives\/Public\/ietf-http-wg\/2002AprJun\/0012.html\">an example of where this issue can show up in practice<\/a>).<\/p>\n\n<p>Where the Web fits in here, is with its contribution of an enormously valuable\npiece of contextual knowledge; <a href=\"http:\/\/www.ietf.org\/rfc\/rfc2396.txt\">RFC 2396<\/a>\naka URIs.  With respect to the example above, I can use URIs instead of strings, where\nthose URIs can be <a href=\"http:\/\/esw.w3.org\/topic\/FollowLinksForMoreInformation\">used<\/a>\nto provide the specifics of <em>which<\/em> blue I meant, by relating it to other colours.<\/p>\n\n<p>There&#8217;s lots to be said about XML, RDF, and why SOA based Web services can\nnever be self-descriptive (hint; too many methods).  But I&#8217;ll leave it at that for now.<\/p>","protected":false},"excerpt":{"rendered":"Kudos to Kendall Clark for stating XML is Not Self-Describing, as I did last month. He writes; Well, I&#8217;ve read too much Wittgenstein (not to mention too much Aquinas, Meister Eckhart, and Julian of Norwich) to think that a name is necessarily a self-description I haven&#8217;t read them at all (8-), but I think I [&hellip;]","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[40],"class_list":["post-156","post","type-post","status-publish","format-standard","hentry","category-uncategorized","tag-xml"],"_links":{"self":[{"href":"http:\/\/www.markbaker.ca\/blog\/wp-json\/wp\/v2\/posts\/156","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.markbaker.ca\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.markbaker.ca\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.markbaker.ca\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.markbaker.ca\/blog\/wp-json\/wp\/v2\/comments?post=156"}],"version-history":[{"count":0,"href":"http:\/\/www.markbaker.ca\/blog\/wp-json\/wp\/v2\/posts\/156\/revisions"}],"wp:attachment":[{"href":"http:\/\/www.markbaker.ca\/blog\/wp-json\/wp\/v2\/media?parent=156"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.markbaker.ca\/blog\/wp-json\/wp\/v2\/categories?post=156"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.markbaker.ca\/blog\/wp-json\/wp\/v2\/tags?post=156"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}