All of the research that I have read so far focuses on intuitions that philosophers make explicit in their analyses. For instance, philosophers who are studying reference spend a lot of time constructing scenarios and consulting their intuitions to test different theories of intuition. However, as Machery et al have shown, the intuitions that western philosophers have about reference may not be shared by members of other cultures (specifically East Asian cultures1). Like I said, this is very interesting, though the implications are still up for debate, but it made me wonder about something that might be even more interesting (at least to me). What about the implicit intuitions that may drive certain philosophical theories?
If the last 30 years of research in cognitive science have taught me anything, it's that many of our basic cognitive intuitions, biases, tendencies, and processes, are unavailable for reflection. This is, in fact, why cognitive psychology is useful. If we could simply discover what our minds are doing through disciplined reflection, we'd have no need for third-person experimental techniques. Fortunately, there's enough about our cognition that is implicit, unconscious, or automatic to keep cognitive psychologists working for centuries to come. My question, then, is how do these implicit aspects of cognition affect philosophical theorizing? It would be beyond the scope of a blog post to look at a bunch of different implicit intuitions or biases, and wonder about their effects on philosophy, so I'll stick to one: psychological essentialism.
While "essentialism" as a metaphysical doctrine has been out of style at various times (and still is today, especially among post-Husserlian continental philosophers), it has been a dominant theme throughout the history of western metaphysics since at least Aristotle. Most recently, and inspired by the work of philosophers like Putnam and Kripke, realists of all sorts, from scientific realists to naturalists in legal philosophy have tended to adopt an essentialist metaphysics, at least about natural kinds. I don't want to address all of the arguments within analytic philosophy for and against essentialism (and to be honest, with the exception of some anti-realist analytic philosophies, I'm simply not qualified to do so), but I do want to wonder about the role of essentialist intuitions in the prominence of essentialism in western thought.
Psychological essentialism is a theory of concepts in cognitive psychology that involves the idea that people are basically essentialists in their reasoning. It doesn't entail metaphysical essentialism, but is instead an epistemological stance toward natural kind concepts, and perhaps other (e.g., functional kind) concepts as well. Psychological essentialism entails that people believe that things "have essences or underlying natures that make them the thing that they are."2. Furthermore, most people are unaware of what those essences are. As Gelman and Diesendruck3 put it:
Essentialism does not entail that people know (consciously or unconsciously) what the essence is. Medin and Ortony (1989)4 referred to this unknown-yet-believed-in entity as an “essence placeholder”. People may implicitly assume, for example, that there is some quality that bears share that confers category identity and causes identifiable surface features, and they may use this belief to guide inductive inferences and explanations without being able to identify any feature or trait as the bear essence. This belief can be considered an unarticulated heuristic rather than a detailed theory.
Under this view, when people encounter an instance of a kind, they use its perceptual features to categorize it, but the category itself is defined by its internal, unperceived essence. This is possible because people, as essentialists, believe that certain diagnostic perceptual properties (e.g., a giraffe's long neck) are causally related to certain underlying properties (genetics, transmission from parents, etc.).
There is a wide variety of evidence for essentialist intuitions, both in adults and in young children. For instance, people tend to classify things based on internal properties, rather than perceptual ones, even after they have undergone radical perceptual transformations (e.g., a skunk given the body of a squirrel)5. Also, at a young age, people tend to make inferences about the future states of natural kinds based on internal properties, rather than facts about the environment (for instance, children infer that apple seeds will become apple trees, regardless of the environmental conditions)6. Furthermore, when people believe that unseen essential properties determine category membership, they are more likely to defer to the opinion of experts7. While psychological essentialism theories of concepts do not capture all instance of categorization8, they do provide insight into many classification phenomena.
Psychological essentialism doesn't entail metaphysical essentialism, necessarily. Medin put it this way9:
If psychological essentialism is bad metaphysics, why should people act as if things had essences? The reason is that it may prove to be good epistemology. One could say that people adopt an essentialist heuristic, namely, the hypothesis that things that look alike tend to share deeper properties (similarities). Our perceptual and conceptual systems appear to have evolved such that the essentialist heuristic is very often correct ....
Still, in light of the recent discussions of intuitions among experimental philosophers, I can't help but wonder about the role of psychological essentialism in the formulation of essentialist metaphysics. If people have implicit essentialist intuitions which mirror the types of essentialist theories proposed by philosophers (notice how the description of psychological essentialism above resembles Kripke's essentialism and causal theories of reference), might the essentialist theories be driven by those intuitions? What would the implications of this be, if true? Might it mean that philosophers, or at least western philosophers, are biased toward essentialist metaphysical theories? Would these biases then need careful scrutiny? Or has the history of to-and-fro debate between essentialists and non-essentialists amounted to a scrutiny of these intuitions, even if they didn't address the intuitions themselves? I'm inclined to think that if the reliance on explicit intuitions calls into question the theories of analytic philosophy, then so too might the unconscious reliance on implicit intuitions, such as psychological essentialism. At least, I think it's an interesting issue to think about.
1 The work of Machery et al was inspired, in part, by the research presented in this book, which is very interesting, but still needs a strong experimental basis for most researchers to begin to take it seriously. It's interesting that some of that basis is coming from philosophers!
2From Medin D. L. (1989) Concepts and conceptual structure. American Psychologist 44: 1469-1481.
3 From Diesendruck G. & Gelman S. A.(1999). Domain differences in absolute judgments of category membership: Evidence for an essentialist account of categorization. Psychonomic Bulletin & Review, 6(2), 338-346.
4 From Medin, D. L. & Ortony, A. (1989). Psychological essentialism. In S. Vosniadou and A. Ortony (Eds.), Similarity and analogical reasoning. New York: Cambridge University Press.
5 See e.g., Conceptual Change in Childhood by Susan Carey; Keil, F. (1986). Conceptual development and category structure. In U. Neisser (Ed.), Concepts and Conceptual Development. Cambridge: Cambridge University Press. Concepts, Kinds, and Cognitive Development by Frank Keil; and Rips, L. J. (1989). Similarity, typicality, and categorization. In S. Vosniadou & A. Ortony (Eds.), Similarity and Analogical Reasoning. New York: Cambridge University Press.
6 Gelman, S. A., & Wellman, H. M. (1991). Insides and essences: Early understandings of the nonobvious. Cognition, 38, 213-244.
7 Deference in Categorisation: Evidence for Essentialism? by Nick Braisby.
8 See Barbara Malt (1994) Water is not H2O. Cognitive Psychology, 27, 41-70, as well as the Braisby paper, for some interesting examples.
9 From Medin D. L. (1989).