Full Idea
Capacities just as much as powers, what particulars and substances are liable to undergo as well as what they are able to do, are explained by reference to what the thing is in itself.
Gist of Idea
Essence explains passive capacities as well as active powers
Source
Harré,R./Madden,E.H. (Causal Powers [1975], 1.II.C)
Book Reference
Harré,R/Madden,E.H.: 'Causal Powers: A Theory of Natural Necessity' [Blackwell 1975], p.13
A Reaction
This is an important warning against trying to give the whole account in terms of powers - unless the capacities and structures and categorical properties can also be explained in terms of the basic powers.