The document discusses causality in health sciences from an epistemological perspective. It argues that causal claims require both probabilistic and mechanistic evidence, and that neither monistic nor pluralistic accounts fully capture the dual aspect of causal epistemology. The document proposes an "epistemic" account of causality, where causal beliefs are determined by the total evidence available to an agent. It also argues that epidemiology establishes "variational causal claims" through comparative studies of how disease risk varies with changes in exposure, rather than measuring regularity or invariance.