Correlation and Causation

Perhaps he addresses this in his book, but in the article Putnam's argument has a subtle flaw. He provides much evidence that involvement civic associations and positive social attributes, such as trust and economic productivity, are correlated. However, his only evidence that civic engagement causes positive social attributes is one very generic sentence without a citation:

"In fact, historical analysis suggested that these networks of organized reciprocity and civic solidarity, far from being an epiphenomenon of socioeconomic modernization, were a precondition for it."

This "suggestion" is the crux of Putnam's argument. All the evidence he presents that there is a correlation is totally irrelevant. What he needs is proof of causation, and the article lacks this.