Xref: utzoo comp.ai:3136 talk.philosophy.misc:1865 sci.lang:3971 Path: utzoo!attcan!uunet!lll-winken!ames!ucsd!rutgers!elbereth.rutgers.edu!harnad From: harnad@elbereth.rutgers.edu (Stevan Harnad) Newsgroups: comp.ai,talk.philosophy.misc,sci.lang Subject: Re: Categorization Summary: On Imposed versus Ad Lib (= Arbitrary) Categorization Message-ID: Date: 19 Jan 89 17:51:00 GMT References: <681@cogsci.ucsd.EDU> <2959@uhccux.uhcc.hawaii.edu> <2899@xyzzy.UUCP> Organization: Rutgers Univ., New Brunswick, N.J. Lines: 136 throopw@xyzzy.UUCP (Wayne A. Throop) of Data General, RTP NC. wrote: " the consequences of not being bigger than a breadbox can be... " every bit as important... as the distinction among fungi is to *you*... " So, other than the motives and goals of the categorizer, there is " nothing to make one categorization more "natural" or "less arbitrary" " than another. Hence, categorization is inherently subjective, " not objective. In my posting I distinguished two senses in which a category might be arbitrary; the first was because it did not pick out a "natural kind" [note that this is also a nonstandard sense of "natural kind"] and the second was because it was merely subjective. I suggested that the first sense of "arbitrary" was not relevant to the problem of how categories were internally represented, because a category might be arbitrary in the first sense, yet still be based on classical features; the features would then simply be picked out because of socially imposed consequences rather than nature-imposed ones. Bigger-than-a-breadbox may be an arbitrary socially imposed distinction for us and a biological imperative to another organism. The difference between these two cases does not much matter for the kind of internal representation you may need to perform this categorization successfully (except inasmuch as differences in size and sensorimotor equipment may entail differences in detectability and means of detection). Subjective categories, on the other hand ("looks pretty to me," "reminds me of his sister") are arbitrary in the second sense, in that there may indeed exist no objective invariant features "out there" whose presence or absence is guiding the judgment. Under those conditions there can be no MIScategorization, no feedback, no consequences. The relevant distinction for modeling category representation, I suggested, was "imposed" vs "ad lib" categorization. For no matter what the source of the imposition, the imposed categories that we can successfully sort must be classical; the ad lib ones need not be. But a model for ad lib categories is no model for imposed ones. [Philosophers, by the way, use "natural kind" in a different way; they would say a natural kind is not merely a category that is picked out by our sense organs because of its biological consequences for us; they would say it's something picked out by empirical scientific inquiry because of its role in a causal theory of the physical world; this would make only things like matter, energy, electrons, galaxies proteins, and perhaps species, etc., the candidates for being natural kinds. Not aspiring to be an ontologist, I am not concerned with this distinction, but only with the cognitive question of how the categories that ARE imposed on us, by nature or nurture, are internally represented so as to allow us to pick them out correctly as we do.] " [The reason we single out a given feature and sort objects in the world " according to it] *must* be (not may be) arbitrary. The choice of " categorization... involves the motives and goals of the categorizer, " and is thus subjective (and objectively arbitrary). I really don't know what you mean by "arbitrary." If a hungry rat that has learned to turn right for food in a maze is behaving arbitrarily, then everything we do is arbitrary and the word loses its meaning. Nor is the rat behaving "subjectively": It may be behaving automatically, just like a machine (though I doubt it). But even if it makes its decision consciously, and hence subjectively, the decision, because it is based on objective consequences, is not MERELY subjective, hence not arbitrary in my second sense. (It's not arbitrary in my first sense either, if nature imposes the maze.) [One can always substitute such an operant-responding situation for a categorization problem by the way, because many operants ARE categorical responses.] " I fail to see why nature is any less arbitrary than a human dictator. " In each case, categorization happens relative to features "important" " to some categorizer. Hence, in this sense, *all* categories are " arbitrary. Then what is NOT arbitrary, and why? And what does "arbitrary" mean? I think that its complement, "nonarbitrary," always has an implicit user- or task-relativity built into it (just as, in a prior posting, I noted that "feature" does, namely, it is a detectable state of affairs -- one that is either directly dectectable by some organism or instrument, or symbolically describable in terms that are themselves the names of categories with features that are detectable by some organism or instrument or ... etc.; this is my "symbol grounding" theory). When a category-name, such as "arbitrary," is applied to "everything," it fails to be informative, for reasons that are deeply related to the internal representation of categories. (I have discussed this in a paper called "Uncomplemented Categories." I think it would be equally uninformative to say that all categories are "metaphorical," for this simply throws out the literal/figurative distinction and the (classical) features underlying it, hence it throws out the meaning of the category "metaphorical.") " one can use Humpty Dumpty's word as a category marker. "It doesn't " say Haynes until *Dumpty* says it says Haynes." is just as objectively " based a category as any other... For ME it becomes objective then, but not for Humpty Dumpty! I can pick it out, using the unfailing cue that Dumpty says so. But Dumpty could be doing it just because of a whim, as the spirit moves him. But before you hasten to inform me that that makes all categories "observer relative," hence arbitrary after all, note that Dumpty and I are not picking out the same categories, even though we're picking out the same objects! I'm picking out the category "things Dumpty calls X." Apart from Dumpty's say-so, there may be NOTHING these things have in common, yet his say-so is enough to make it a classical category for me. But not for Dumpty! He has no external cue. He's not picking out the things so-and-so says are X, based reliably and validly on the cue of so-and-so's say-so. God knows HOW he's picking them out. He's using some subjective, internal cue; perhaps just a momentary, spontaneous impulse. That makes it a different category, even though it has the same members as mine; and a subjective, arbitrary one at that. (I trust there's no problem with the idea that different categories can have the same members, as with Frege's morning-star/evening-star/Venus, or sets in mathematics that differ in their intensions but not their extensions, etc.) " no categorizations are arbitrary in [the second] sense. Humpty Dumpty's, for example, is; or perhaps it's better to say that, being arbitrary in the second sense, it's not really a category at all. " it may well be that people in practice don't categorize in order to " derive "X-is-like-Y" measures, but rather pseudocategorize according to " these measures. I can't understand this point. To me, to categorize is to sort instances in a reliable, correct, objective, all-or-none fashion. If it's not reliable, correct or all-or-none, it's not categorization (or not categorical to the degree that it's not reliable, correct or all-or-none). If it's not objective, it's subjective; then you can call it what you like, because I have no idea what's being sorted, and on what basis. -- Stevan Harnad INTERNET: harnad@confidence.princeton.edu harnad@princeton.edu srh@flash.bellcore.com harnad@elbereth.rutgers.edu harnad@princeton.uucp BITNET: harnad@pucc.bitnet CSNET: harnad%princeton.edu@relay.cs.net (609)-921-7771