7.5. Implementing Categories
Categories are conceptual constructs that we use in a mostly invisible way when we talk or think about them. When we organize our kitchens, closets, or file cabinets using shelves, drawers, and folders, these physical locations and containers are visible implementations of our personal category system, but they are not the categories. This distinction between category design and implementation is obvious when we follow signs and labels in libraries or grocery stores to find things, search a product catalog or company personnel directory, or analyze a set of economic data assembled by the government from income tax forms. These institutional categories were designed by people prior to the assignment of resources to them.
This separation between category creation and category implementation prompts us to ask how a system of categories can be implemented. We will not discuss the implementation of categories in the literal sense of building physical or software systems that organize resources. Instead, we will take a higher-level perspective that analyzes the implementation problem to be solved for the different types of categories discussed in §7.3, and then explain the logic followed to assign resources correctly to them.
7.5.1. Implementing Enumerated Categories
Categories defined by enumeration are easy to implement. The members or legal values in a set define the category, and testing an item for membership means looking in the set for it. Enumerated ...