The contents supply the key. He declares that he shall criticize Leibniz and Wolff (ii, 1:7). He rejects the doctrine of pre-established harmony according to which substances do not interact, rejecting Leibniz’s claim (Monadology 1714: sec. 7) that substances have no “windows”. For Kant, they do. Following Knutzen (who had earned his doctorate with a similar critique in 1735) he says that substances change each other’s states by their mutual actions (#4, 1:19). He also rejects Wolff’s notion of a “moving force”.  Kant argues (#3, 1:18) that force and motion have little to do with one another. Force is not so much about motion and more about being. So a “moving force” is a misnomer. For Kant, living forces are better described as the dynamic source for nature, an “active force” or a vis activa.