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Fall 2015




The accepted narrative treats John Stuart Mill's Kinds as the historical prototype for our natural kinds, but Mill actually employs two separate notions: Kinds and natural groups. Considering these, along with the accounts of Mill's 19th-century interlocutors, forces us to recognize two distinct questions. First, what marks a natural kind as worthy of inclusion in taxonomy? Second, what exists in the world that makes a category meet that criterion? Mill's two notions offer separate answers to the two questions: natural groups for taxonomy, and Kinds for ontology. This distinction is ignored in many contemporary debates about natural kinds and is obscured by the standard narrative which treats our natural kinds just as a development of Mill's Kinds.


An earlier version was presented at the 2014 Philosophy of Science Association meeting under the title 'What the 19th century knew about taxonomy and the 20th forgot' and at MiddleburyCollege.

Publisher Acknowledgement:

Magnus, P. D. (2015). John Stuart Mill on Taxonomy and Natural Kinds. HOPOS: The Journal of the International Society for the History of Philosophy of Science, 5(2), 269–280.



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