Full Idea
If two propositions (about perfections) are incompatible, that cannot be demonstrated without a resolution of the terms, for otherwise their nature would not enter into the ratiocination.
Gist of Idea
Perfections must have overlapping parts if their incompatibility is to be proved
Source
Gottfried Leibniz (New Essays on Human Understanding [1704], App X)
Book Reference
'The Existence of God', ed/tr. Hick,John [Macmillan 1964], p.38
A Reaction
If God is omnipotent and wholly free, these appear to be fully separate perfections. But it is their implications (can God decide to do otherwise, given His foreknowledge?) which lead to a problem. So this analyis of contradiction is wrong.
Related Idea
Idea 1414 A perfection is a simple quality, which is positive and absolute, and has no limit [Leibniz]