Family resemblance concepts are structured by OR, the set-theoretic union.

Evidence

If we ask what logical operator generates the pattern in table 2.2, the answer is OR. Of course, the set theoretic partner to OR is the union. Hence we have the following mathematical principle for the family resemblance concept structure: The family resemblance concept structure is mathematically modeled by OR or the union in set theory. — Gary Goertz, Social Science Concepts, 273

Categorization

• DEFINE: Names the formal logical operator (OR/union) that underlies the fuzzy, non-necessary-condition structure of family resemblance concepts.
• XREF: Connects to any prior chapter material on necessary-and-sufficient conditions and to prototype/radial category debates in cognitive science.