Concepts are theories about what constitutes a phenomenon

Evidence

Concepts are theories about ontology: they are theories about the fundamental constitutive elements of a phenomenon. … I use the term in a straightforward way to designate the core characteristics of a phenomenon and their interrelationships. For example, we can ask about what constitutes a welfare state. Typically, these are states that provide goods and services like unemployment insurance, medical services, and retirement benefits. To be a welfare state is to provide these goods and services. — Gary Goertz, Social Science Concepts and Measurement, 133

Categorization

• DEFINE: Reframes ‘concept’ from a label or definition into an ontological claim about constitutive elements — the book’s foundational move.
• XREF: Connects to earlier selection work on how classification systems constitute infrastructures — here the constitutive move is at the level of individual concepts rather than whole taxonomies.