Full Idea
The primary mechanical axiom is that the whole cause and the entire effect have the same power [potentia]. ..This depends on the definition of cause, effect and power.
Gist of Idea
Because of the definitions of cause, effect and power, cause and effect have the same power
Source
Gottfried Leibniz (De arcanus motus [1676], 203), quoted by Daniel Garber - Leibniz:Body,Substance,Monad 6
Book Reference
Garber,Daniel: 'Leibniz: Body, Substance, Monad' [OUP 2009], p.237
A Reaction
This is a useful reminder that if one is going to build a metaphysics on powers (which I intend to do), then the conservation laws in physics are highly relevant.
Related Idea
Idea 15095 A property's causal features are essential, and only they fix its identity [Shoemaker]