According to David Hume our idea of a necessary connection between what we call cause and effect is produced when repeated observation of the conjunction of two events determines the mind to consider one upon the appearance of the other. No matter how we interpret Hume's theory of causation this explanation of the genesis of the idea of necessity is fraught with difficulty. I hope to show, looking at the three major interpretations of Hume's causal theory, that his account is (...) contradictory, plainly wrong, or inherently impossible to verify. (shrink)