Full Idea
The Copernican account is the truest theory, that is, the most intelligible theory and the only one capable of an explanation sufficient for a person of sound reason.
Gist of Idea
The Copernican theory is right because it is the only one offering a good explanation
Source
Gottfried Leibniz (On Copernicanism and Relativity of Motion [1689], p.92)
Book Reference
Leibniz,Gottfried: 'Philosophical Essays', ed/tr. Arlew,R /Garber,D [Hackett 1989], p.92
A Reaction
The word 'intelligible' here seems to be linked to the notion of a best explanation.