How do we establish singular causal claims? It seems we do this all the time, from courtrooms to cloud chambers. Nevertheless, there is a strong lobby in the evidence-based medicine and policy movements that argues that we cannot make reliable causal judgments about single cases in these areas. So we cannot tell whether a policy or treatment ‘worked’ for any specific individual. The reason often seems rooted in the idea that a singular causal claim, if not equivalent to, at least implies, a counterfactual claim: c caused e e would not have occurred had c not occurred. Couple this with the idea that we cannot have compelling evidence about what would have happened in any actual case had things been different and you end up with serious doubts about the possibility of warranting singular causal claims.
Cartwright, N. (2015). Single Case Causes: What is Evidence and Why