“Why Correlation Usually ≠ Causation”, Gwern2014-06-24 (, , , , , , ; backlinks; similar)⁠:

Correlations are oft interpreted as evidence for causation; this is oft falsified; do causal graphs explain why this is so common, because the number of possible indirect paths greatly exceeds the direct paths necessary for useful manipulation?

It is widely understood that statistical correlation between two variables ≠ causation. Despite this admonition, people are overconfident in claiming correlations to support favored causal interpretations and are surprised by the results of randomized experiments, suggesting that they are biased & systematically underestimate the prevalence of confounds / common-causation. I speculate that in realistic causal networks or DAGs, the number of possible correlations grows faster than the number of possible causal relationships. So confounds really are that common, and since people do not think in realistic DAGs but toy models, the imbalance also explains overconfidence.