Full Idea
Whatever concerns reasonable substances (the minds of men) is more naturally explained by the consideration of ends, whereas other substances (bodies) are better explained by efficient causes.
Gist of Idea
Minds are best explained by their ends, and bodies by efficient causes
Source
Gottfried Leibniz (Geometrical Method and Metaphysics [1712], p.89)
Book Reference
Leibniz,Gottfried: 'Leibniz Selections', ed/tr. Wiener,Philip P. [Scribners 1951], p.89
A Reaction
That is, I take it, that the type of causal explanation considered most appropriate is the one that leads to the greatest understanding. So there is no absolute or correct answer as to which type of causation is the more important.