 A cause is regularly followed by its effect. This idea is at the core of regularity theories of causation. The most influential regularity theory can be found in Hume (1739). The theory has been refined by Mill (1843) who insisted that the relevant regularities are laws of nature. Further refinements used to enjoy popularity until David Lewis (1973) criticized the regularity theory and proposed an analysis of causation in terms of counterfactuals (see the entry on  counterfactual theories of causation).  Since then, counterfactual theories of causation have risen and regularity theories have more and more fallen into disuse.