Full Idea
The metaphysics of Leibniz was explicitly based upon the doctrine that every proposition attributes a predicate to a subject and (what seemed to him almost the same thing) that every fact consists of a substance having a property.
Clarification
In 'the sky is blue', 'the sky' is the subject, and 'is blue' is the predicate
Gist of Idea
Leibniz bases everything on subject/predicate and substance/property propositions
Source
Bertrand Russell (My Philosophical Development [1959], Ch.5)
Book Reference
Russell,Bertrand: 'My Philosophical Development' [Routledge 1993], p.48
A Reaction
I think it is realised now that although predicates tend to attribute properties to things, they are far from being the same thing. See Idea 4587, for example. Russell gives us an interesting foot in the door of Leibniz's complex system.
Related Idea
Idea 4587 From the property predicates P and Q, we can get 'P or Q', but it doesn't have to designate another property [Heil]