Predicting when contact works does not explain how it works.

Evidence

The original hypothesis says nothing about the processes by which contact changes attitudes and behavior. It predicts only when contact will lead to positive change, not how and why the change occurs. A broader theory of intergroup contact requires an explicit specification of the processes involved, which I provide below. — Thomas F. Pettigrew, Intergroup Contact Theory, 35

Categorization

• DEEPTHINKING: A clean statement of the distinction between predictive and mechanistic theory — the gap between knowing the conditions and knowing the causal machinery. Worth sitting with whenever evaluating any social-science model.