...In the standard empiricist view, constant conjunctions of events are both necessary and sufficient for a causal law. In the realist view, constant conjunctions of events are neither necessary nor sufficient.
....To base one's analysis on the constant conjunction of events is to conflate three domains, according to Bhaskar (1978) (a) the empirical, which consists of experiences and sense impressions; (b) the actual, which consists of events; and (c) the real, which consists of the entities and structures that produce events.
...Reality... ...is stratified. Events are explained by underlying structures, which may be explained eventually by other structures at still deeper levels.
Ernest R House Realism In Research from Educational Researcher Vol 20 No 6 (1991) p.4-5