Taxonomic definitions in social science, with firms, markets and institutions as case studies

Definitions are crucial for institutional analysis. This article explains the nature of taxonomic definitions, with particular attention to their use in economics and other social sciences. Taxonomic definitions demarcate one species of entity from another. They are vital for the communication of meaning between scientists, who must share some basic conception of what types of entity they are investigating, to establish a division of labour over subsequent theoretical analysis and empirical investigation of the type of entity defined. Generally, taxonomic definitions build on past usage and are parsimonious: they are not meant to be explanations or descriptions. By contrast, overloaded taxonomic definitions can create square-one disagreement about what is being investigated. As illustrative examples, the paper considers different degrees of progress with attempts to define firms, markets and institutions.