The “categorization as a theoretical tool” framework is delineated to clarify how innovation is possible even though candidates for exchange face a “categorical imperative” – pressure from their audience to adopt the conventional practices associated with existing categories. The key insight is that categorization is generally a useful tool for sorting and screening exchange opportunities. This insight is developed to suggest how the nature of the imperative varies with the audience’s objectives and the theory of value it espouses and how the strength of the imperative varies with the social challenges and opportunities for engaging in, and learning from, experiments with unconventionality.