Mathematical aggregation must be faithful to a concept’s semantics.

Evidence

A key requirement is that the mathematical operations match the semantics of the concept. For example, if the concept states that a given feature is necessary for the concept then the mathematics involving that feature must be faithful to the idea of a necessary condition. — Gary Goertz, Social Science Concepts and Measurement, 151

Categorization

• XREF: Connects to measurement-validity literature and to the concept-stretching debates in the adjacent chapters.
• SEED: Angle: a piece on how averaging (μ) smuggles in ‘substitutability’ assumptions that silently contradict concepts defined by necessary conditions.
• corroborated: 2 independent passages support this claim — Gary Goertz, Social Science Concepts and Measurement, 151