more on this theme | more from this thinker | more from this text
Full Idea
Even in the most contingent truths, there is always something to be conceived in the subject which serves to explain why this predicate or event pertains to it, or why this has happened rather than not.
Gist of Idea
To fully conceive the subject is to explain the resulting predicates and events
Source
Gottfried Leibniz (Letters to Antoine Arnauld [1686], 1686.06)
Book Ref
Leibniz,Gottfried: 'The Leibniz-Arnauld Correspondence', ed/tr. Mason,HT/Parkinson,GHR [Manchester UP 1967], p.50
A Reaction
The last bit, about containing what has happened, seems absurd, but the rest of it makes sense. It is just the Aristotelian essentialist view, that a full understanding of the inner subject will both explain and predict the surface properties.
Related Idea
Idea 13077 Basic predicates give the complete concept, which then predicts all of the actions [Leibniz]