OXFORD UNIVERSITY PRESS, MAY 2016Psychological Fluency: Natural Kinds, Prototypicality, and Beauty in the Mean
Science is about special kinds of classes in nature. It is not interested in phony hybrid objects like a salamander 54 miles southeast of the Liberty Bell or elements with atomic numbers that are the sum of pets you have. Instead, science is interested in “carving nature at its joints,” to use the apt Platonic phrase further popularized by Quine. Once the theory carves those joints, it has identified Natural Kinds, objects in nature that play a taxonomic role in a mature, working science. What makes these kinds natural is that it is nature itself, not human practices of categorization, that fixes whether an object belongs in one class or another. Species and crystals, copper and maple trees, and visual transduction and lexical priming are ...
