Full Idea
I recognize a primitive entelechy in the active force found in motion, something analogous to the soul, whose nature consists in a certain law of the same series of changes.
Gist of Idea
An entelechy is a law of the series of its event within some entity
Source
Gottfried Leibniz (Letters to Burcher De Volder [1706], 1699.03.24)
Book Reference
Leibniz,Gottfried: 'Philosophical Essays', ed/tr. Arlew,R /Garber,D [Hackett 1989], p.173
A Reaction
This is his 'law-of-the-series', which is a speculative attempt to pin down the character of the active essence of things which gives rise to activity. The law of such activity is within the things themselves, as scientific essentialists claim.