Full Idea
The Humean effort to ground the intuition of causal directionality on temporal priority of cause alone fails, because in fact some causes and effects are simultaneous. The moving of the knife and separation of the orange occur together.
Gist of Idea
Humean accounts of causal direction by time fail, because cause and effect can occur together
Source
Harré,R./Madden,E.H. (Causal Powers [1975], 6.IV)
Book Reference
Harré,R/Madden,E.H.: 'Causal Powers: A Theory of Natural Necessity' [Blackwell 1975], p.114
A Reaction
Since I take causation to be largely concerned with movements of 'energy', this idea that cause and effect might be simultaneous sounds more like a matter of pragmatics and convention. Moving the knife and moving the orange are different.