 Analytic philosophers of history most commonly approached these issues on the basis of a theory of causation drawn from positivist philosophy of science. This theory is ultimately grounded in Humean assumptions about causation: that causation is nothing but constant conjunction. So analytic philosophers were drawn to the covering-law model of explanation, because it appeared to provide a basis for asserting historical causation. As noted above, this approach to causal explanation is fatally flawed in the social sciences, because universal causal regularities among social phenomena are unavailable. So it is necessary either to arrive at other interpretations of causality or to abandon the language of causality. A second approach was to define causes in terms of a set of causally relevant conditions for the occurrence of the event—for example, necessary and/or sufficient conditions, or a set of conditions that enhance or reduce the likelihood of the event. This approach found support in “ordinary language” philosophy and in analysis of the use of causal language in such contexts as the courtroom (Hart and Honoré 1959). Counterfactual reasoning is an important element of discovery of a set of necessary and/or sufficient conditions; to say that \(C\) was necessary for the occurrence of \(E\) requires that we provide evidence that \(E\) would not have occurred if \(C\) were not present (Mackie 1965, 1974). And it is evident that there are causal circumstances in which no single factor is necessary for the occurrence of the effect; the outcome may be overdetermined by multiple independent factors.