publication-status: Acceptedtypes: ArticleAuthor's version of a paper subsequently published in Biological Theory. Please cite the published version by following the DOI link.Scientific classification has long been recognized as involving a specific style of reasoning and doing
research, and as occasionally affecting the development of
scientific theories. However, the role played by classificatory activities in generating theories has not been closely
investigated within the philosophy of science. I argue that
classificatory systems can themselves become a form of
theory, which I call classificatory theory, when they come
to formalize and express the scientific significance of the
elements being classified. This is particularly evident in
some of the classification practices used in contemporary
experimental biology, such as bio-ontologies used to
classify genomic data and typologies used to classify
‘‘normal’’ stages of development in developmental biology.
In this paper, I explore some characteristics of classificatory theories and ways in which they differ from other
types of scientific theories and other components of scientific epistemology, such as models and background
assumptions.Economic and Social Research Council (ESRC
