Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!utgpu!water!watmath!clyde!rutgers!ames!sdcsvax!ucbvax!hci.hw.ac.UK!gilbert From: gilbert@hci.hw.ac.UK.UUCP Newsgroups: comp.ai.digest Subject: Re: Natural Kinds (Re: AIList Digest V5 #186) Message-ID: <115@glenlivet.hci.hw.ac.uk> Date: Thu, 13-Aug-87 08:52:52 EDT Article-I.D.: glenlive.115 Posted: Thu Aug 13 08:52:52 1987 Date-Received: Tue, 18-Aug-87 01:07:34 EDT References: Sender: daemon@ucbvax.BERKELEY.EDU Reply-To: Gilbert Cockton Distribution: world Organization: Scottish HCI Centre Lines: 65 Approved: ailist@stripe.sri.com In article MINSKY@OZ.AI.MIT.EDU writes: > >In my view, Wittgenstein missed the point because he focussed on >"structure" only. What we have to do is also take into account the >"function", "goal", or "intended use" of the definition. My trick is >to catch the idea between two descriptions, structural and functional. >Consider a chair, for example. > > STRUCTURE: A chair usually has a seat, back, and legs - but > any of them can be changed in so many ways that it is hard > to make a definition to catch them all. > > FUNCTION: A chair is intended to be used to keep one's bottom > about 14 inches off the floor, to support one's back > comfortably, and to provide space to bend the knees. > >If you understand BOTH of these, then you can make sense of that list >of structural features - seat, back, and legs - .......[ cut ]...... >........This also helps us understand how to deal with "toy chair" and >such matters. Is a toy chair a chair? The answer depends on what you >want to use it for. It is a chair, for example, for a suitable toy >person, or for reminding people of "real" chairs, or etc. a toy chair is a chair if people say it is a chair. I didn't vote for any lexicographer to go and prescribe our language. Whilst agreement on structure is possible by an appeal to sense-data mediated by a culture's categories, agreement on function is less likely. How do we know that an object has a function? Whilst the prime use of a chair, is indeed for sitting on, this does not preclude it's use for other functions - now don't these go back to structure? Or are they related to intention (i.e. when someone hits you on the head with a chair)? Function is a dangerous word, as it pretends a closure well-suited to the description of a well-ordered, unchanging world. I hope that this new focus doesn't take AI down the path of American post-war sociology, where Talcott Parson's functionalism recast the great American dream as the 'natural' functions of all societies. In short, nothing, no "das ding an Sich", has a function. People give things functions. Give a polaroid to someone in a part of the world where cameras aren't understood, and the function is not going to jump out and reveal the essence of the object. In fact, museums of ethnography are full of examples of industrial products put to the strangest uses. There was also once a spate of jokes about what the Japanese did when faced with a western water-closet, and recently a book on Japanese etiquette has warned Westerners about using their hankerchiefs to blow their nose on - we are told that this is not the function of a hankerchief in Japan! So, don't ignore the social. It's the only reality there is. Wittgenstein may have missed your preferred point, but I think you're ignoring his observations. Had he been alive in the '60s, I've a feeling that the growth of sociology would have provided him with more substance for thought than GPS and the Want-P predicate. BTW - what is the function of a Want-P predicate, and what would a Japanese do with a hankerchief afterwards? :-) Times change, the world changes, knowledge-bases stagnate. -- Gilbert Cockton, Scottish HCI Centre, Ben Line Building, Edinburgh, EH1 1TN JANET: gilbert@uk.ac.hw.hci ARPA: gilbert%hci.hw.ac.uk@cs.ucl.ac.uk UUCP: ..{backbone}!mcvax!ukc!hwcs!hci!gilbert