It seems to me that when people say "correlation is not causation", they typically mean you can't learn about a causal relationship by just looking at the corre

It seems to me that when people say "correlation is not causation", they typically mean you can't learn about a causal relationship by just looking at the correlation. The article makes the converse statement: you can't infer the absence of a causal relationship from the absence of correlation, or equivalently (contrapositive), even when you know there is a causal relationship, it won't necessarily lead to a visible correlation in the data.