Full Idea
Humeans say there can be no element of necessity in the causal relation because the conjunction of a description of a cause with the negation of a description of its usual effect is never self-contradictory.
Gist of Idea
Humeans say there is no necessity in causation, because denying an effect is never self-contradictory
Source
Harré,R./Madden,E.H. (Causal Powers [1975], 3.I)
Book Reference
Harré,R/Madden,E.H.: 'Causal Powers: A Theory of Natural Necessity' [Blackwell 1975], p.45
A Reaction
We might say there actually is a contradiction, because you assert the existence of something, and then deny that existence by denying that the effect could occur. If the object is inert this is wrong, but if it is defined by its powers it is right.