Full Idea
Everything takes place in souls as if there were no body, and everything takes place in bodies as if there were no souls.
Gist of Idea
Souls act as if there were no bodies, and bodies act as if there were no souls
Source
Gottfried Leibniz (Principle of Life and Plastic Natures [1705], p.198)
Book Reference
Leibniz,Gottfried: 'Leibniz Selections', ed/tr. Wiener,Philip P. [Scribners 1951], p.198
A Reaction
I don't think I have ever encountered a modern thinker who accepts this view. Leibniz rejected Occasionalism, but his account depends entirely on the role of God, to set up the pre-established harmony. Why would God do that?