Ioannidis and Psillos (2018) on mechanisms

“Mechanisms are causal pathways described in theoretical language that have certain functions; these descriptions can be enriched by offering more detailed or fine‐grained descriptions; the same mechanism can then be described at various levels using different theoretical vocabularies (e.g., cytological vs biochemical descriptions in the case of apoptosis); lastly, the descriptions of biomedically important mechanisms are often such that they contain specific causal information that can be used to make interventions for therapeutic purposes.” (Ioannidis & Psillos, 2018, pp. 1180–1)

Ioannidis, S., & Psillos, S. (2018). Mechanisms in practice: A methodological approach. Journal of Evaluation in Clinical Practice, 24(5), 1177–1183.