Full Idea
Every time we find some quality in a subject, we ought to think that, if we understood the nature of this subject and of this quality, we should conceive how this quality could result from it.
Gist of Idea
If you fully understand a subject and its qualities, you see how the second derive from the first
Source
Gottfried Leibniz (New Essays on Human Understanding [1704], Pref)
Book Reference
Leibniz,Gottfried: 'Philosophical Writings', ed/tr. Parkinson,G.H.R. [Dent 1973], p.168
A Reaction
Thus (in Kripke's analogy) God cannot make 'subjects' on Thursday and then add 'qualities' on Friday. Add the point that all subjects are physical, and I say you have the whole story. The physical entails the mental. The laws result from the qualities.
Related Idea
Idea 13191 The properties of a thing flow from its essence [Leibniz]