Full Idea
One must always explain nature along mathematical and mechanical lines, provided one knows that the very principles or laws of mechanics or of force do not depend upon mathematical extension alone but upon certain metaphysical reasons.
Gist of Idea
Nature is explained by mathematics and mechanism, but the laws rest on metaphysics
Source
Gottfried Leibniz (Letters to Antoine Arnauld [1686], 1686.07.4/14 X)
Book Reference
Leibniz,Gottfried: 'The Leibniz-Arnauld Correspondence', ed/tr. Mason,HT/Parkinson,GHR [Manchester UP 1967], p.66
A Reaction
I like this, and may even use it as the epigraph of my masterwork. Recently Stephen Hawking (physicist) has been denigrating philosophy, but I am with Leibniz on this one.