Dual Character Concepts

Dual Character Concepts Joshua Knobe (joshua.knobe@yale.edu) Program in Cognitive Science, P.O. Box 208306 New Haven, CT 06520-8306 USA Sandeep Prasada (sprasada@hunter.cuny.edu) Department of Psychology, 695 Park Ave New York, NY 10065 USA Abstract Four experiments provided evidence for a class of ‘dual character concepts.’ Such concepts are characterized in terms of both (a) concrete features and (b) abstract values. Three experiments found that when an object fulfills only one of these two criteria, it is judged to be a category member in one sense but not in another. A fourth experiment showed that dual character concepts also support a distinct form of normative judgment. Keywords: Concepts; natural kinds; normativity. Imagine a physics professor who spends her days writing out equations but who clings dogmatically to a certain theoretical perspective against all empirical evidence. Does this person genuinely count as a scientist? In a case like this, one might feel that both answers are in some sense correct. It might therefore seem right to say: (1) There is a sense in which she is clearly a scientist, but ultimately, if you think about what it really means to be a scientist, you would have to say that she is not a scientist at all. Now suppose we come upon a person who has never been trained in formal experimental methods but who approaches everything in life by systematically revising her beliefs in light of empirical evidence. In a case of this latter type, it might seem appropriate to make the converse sort of statement: (2) There is a sense in which she is clearly not a scientist, but ultimately, if you think about what it really means to be a scientist, you would have to say that she truly is a scientist. To the extent that people do in fact show these patterns of intuition, we might conclude that they actually have two different characterizations of what it means to be a scientist – one in terms of concrete activities (conducting experiments, formulating theories, etc.), the other in terms of more abstract values (an impartial quest for empirical truth). The implicit assumption in most work on conceptual representation seems to have been that concepts characterize members of a category in a single way – whether via the representation of a definition, a prototype, salient exemplars, or a theory (for a review, see Murphy, 2002). Could current approaches to conceptual representation accommodate concepts that provide two ways of characterizing their members? Or must they be modified to handle such concepts? Before these broader issues can be addressed, we need a better understanding of the concepts in question. The experiments in this paper are aimed at providing this information. Dual character concepts The experiments seek to demonstrate that there is a whole class of concepts which are represented via both (a) a set of concrete features and (b) a set of abstract values that the concrete features are seen as realizing. These two representations are intrinsically related, but they are nonetheless distinct, and they can sometimes yield opposing verdicts about whether a particular object counts as a category member or not. We will argue that this pattern of intuitions can be found across a broad array of different concepts: SCIENTIST , ART , CRIMINAL , TEACHER , ROCK MUSIC , MOTHER , LOVE , and many others. These concepts, we suggest, differ fundamentally from the types of concepts that have been studied in the existing literature (e.g., from natural kind concepts). We will refer to them as dual character concepts. Not all concepts, however, are dual character concepts. Take the concept BUS DRIVER . It would be odd to say something like (3) of a person who does not have any of the features normally associated with bus drivers. (3) There is a sense in which she is clearly not a bus driver, but ultimately, if you think about what a bus driver really is, you would have to say that she truly is a bus driver. This latter concept does not appear to provide an abstract way of characterizing a category. Similarly for a wide range of other concepts: BUS DRIVER , PHARMACIST , ACQUAINTANCE , RUSTLING NOISE , SECOND COUSIN , and so on. These concepts, we suggest, do not have a dual character. We will use them in our studies as control concepts. The role of normative considerations Dual character concepts provide two distinct ways of characterizing category members: one based on concrete features, the other based on what we have been calling ‘abstract values.’ The latter way of characterizing category