Full Idea
I relegate derivative forces to the phenomena, but I think that it is clear that primitive forces can be nothing other than the internal strivings of simple substances.
Gist of Idea
Derivate forces are in phenomena, but primitive forces are in the internal strivings of substances
Source
Gottfried Leibniz (Letters to Burcher De Volder [1706], 1705.01), quoted by Daniel Garber - Leibniz:Body,Substance,Monad 8
Book Reference
Garber,Daniel: 'Leibniz: Body, Substance, Monad' [OUP 2009], p.314
A Reaction
I like 'internal strivings', which sounds to me like the Will to Power (Idea 7140). There seems to be an epistemological challenge in trying to disentangle the derivative forces from the primitive ones.
Related Idea
Idea 7140 Chemical 'laws' are merely the establishment of power relations between weaker and stronger [Nietzsche]