Full Idea
To find real entities I had recourse to a unified formal atom. Hence I rehabilitated the substantial forms in a way to render them intelligible. I found that their nature consists in force, from which follows something analogous to sensation and appetite.
Gist of Idea
My formal unifying atoms are substantial forms, which are forces like appetites
Source
Gottfried Leibniz (New system of communication of substances [1695], p.139)
Book Reference
Leibniz,Gottfried: 'Philosophical Essays', ed/tr. Arlew,R /Garber,D [Hackett 1989], p.139
A Reaction
[several lines are here compressed] This passage sums up the key to Leibniz's essentialism, which I take to be a connection between Aristotelian form and the physicists' notion of force. This gives us a modern version of Aristotelianism for science.