Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!uunet!seismo!uwvax!rutgers.rutgers.edu!sri-spam!ames!sdcsvax!ucbvax!SAIL.STANFORD.EDU!JMC From: JMC@SAIL.STANFORD.EDU (John McCarthy) Newsgroups: comp.ai.digest Subject: re: [Robert L. Causey: Natural Kinds] Message-ID: <8707200505.AA05770@ucbvax.Berkeley.EDU> Date: Sun, 19-Jul-87 02:15:00 EDT Article-I.D.: ucbvax.8707200505.AA05770 Posted: Sun Jul 19 02:15:00 1987 Date-Received: Tue, 21-Jul-87 00:43:04 EDT Sender: daemon@ucbvax.BERKELEY.EDU Distribution: world Organization: The ARPA Internet Lines: 21 Approved: ailist@stripe.sri.com [In reply to message from AI.CAUSEY@R20.UTEXAS.EDU sent Sat 18 Jul 87.] I agree with Bob Causey's comments and agree that the open questions he lists are unsolved and important. I have one caveat. The distinction between nomological and functional kinds exists in sufficiently elaborate mental structures, but I don't think that under 2 year olds make the distinction, i.e. have different mechanisms for learning them. For this reason, it is an open question whether it should be a primary distinction for robots. In a small child's world, chairs are distinguished from other objects by appearance, not by function. Evidence: a child doesn't refer to different appearing objects on which he can also sit as chairs. Concession: there may be such a category "sittable" in "mentalese", and languages with such categories might be as easily learnable as English. What saves the child from having to make the distinction between kinds of kinds at an early age is that so many of the kinds in his life are distinguishable from each other in many ways. The child might indeed be fooled by the different generations of calculator, but usually he's lucky. I hope to comment later on how robots should be programmed to identify and use kinds.