Hume's 'Two Definitions' of Causation and the Ontology of 'Double Existence' (revised) with an Appendix 2021

[Originally published in Hume Studies 10 (1): 1-25. 1984.] This essay provides an interpretation of Hume’s “two definitions” of causation. It argues that the two definitions of causation must be interpreted in terms of Hume’s fundamental ontological distinction between perceptions and (material) objects. Central to Hume’s position on this subject is the claim that, while there is a natural tendency to suppose that there exist (metaphysical) causal powers in objects themselves, this is a product of our failure to distinguish perceptions and objects. Properly understood, our idea of causation involves no suggestion that there is anything more to causation among objects themselves than constant conjunction. A new appendix is added, discussing the relevance of this interpretation to the recent debate concerning Hume’s “causal realism.” [The original of this article was published in HUME STUDIES 10 (1984), 1 - 25, with corrections added separately in the following issue.]