Full Idea
That thing from whose state a reason for the changes is most readily provided is adjudged to be the cause. ...Causes are not derived from a real influence, but from the providing of a reason.
Gist of Idea
The cause of a change is not the real influence, but whatever gives a reason for the change
Source
Gottfried Leibniz (Specimen inventorum [1689], A6.4.1620), quoted by Daniel Garber - Leibniz:Body,Substance,Monad 5
Book Reference
Garber,Daniel: 'Leibniz: Body, Substance, Monad' [OUP 2009], p.213
A Reaction
Leibniz is not denying that there are real influences. He seems to be offering the thesis which I am pursuing, that the need for explanation is the crucial factor in shaping the structure of our metaphysics.