Messy Chemical Kinds

Following Kripke ([1980]) and Putnam ([1973], [1975]), the received view of chemical kinds has been a microstructuralist one. To be a microstructuralist about chemical kinds is to think that membership in said kinds is conferred by microstructural properties. Recently, the received microstructuralist view has been elaborated and defended (for example, Hendry [2006], [2012]), but it has also been attacked on the basis of complexities, both chemical (for example, Needham [2011]) and ontological (for example, LaPorte [2004]). Here, I look at which complexities really challenge the microstructuralist view; at how the view itself might be made more complicated in order to accommodate such challenges; and finally, at what this increasingly complicated picture implies for our standard assessment of chemical kindhood—primarily, for the widespread assumption that chemical kinds in general are more neat and tidy than those messy biological ones. 1 The Received (Microstructuralist) View2 A Taxonomy of Chemical Kinds3 Atomic Number (Z = 79)4 H2O, H3O+, OH−, and More5 Complicating the Microstructuralist Picture6 Concrete and Other Mixtures7 Macromolecules, Especially Proteins8 Abandoning Sameness of Elemental Composition9 Not So Different after All