"What Water Tells Us about the Mind:
                 Psychological Essentialism Refuted?"
                           Michael Strevens
                         Philosophy, Stanford

Psychological essentialism is an extremely attractive theory of the
nature of certain concepts that explains a number of interesting facts
about human inference and promises even to contribute to the
philosophical study of the relation between mind and world. Its
central posit is that humans conceive of certain categories as being
characterized by an unobserved central property, or essence. Some
psychologists and philosophers have argued against this thesis of
_psychological essentialism_ by claiming that it cannot explain the
way we think about various substances, including water. Essentialists
have responded to these arguments in a number of interesting ways. The
purpose of this paper is to describe and evaluate these arguments. My
conclusion: despite the essentialists' best efforts, water continues
to create significant problems for essentialism.