Full Idea
The sufficient reason for God's choice can be found only in the fitness (convenance) or in the degree of perfection that the several worlds possess.
Gist of Idea
God's sufficient reason for choosing reality is in the fitness or perfection of possibilities
Source
Gottfried Leibniz (Exigency to Exist in Essences [1690], p.92)
Book Reference
Leibniz,Gottfried: 'Leibniz Selections', ed/tr. Wiener,Philip P. [Scribners 1951], p.92
A Reaction
The 'fitness' of a world and its 'perfection' seem very different things. A piece of a jigsaw can have wonderful fitness, without perfection. Occasionally you get that sinking feeling with metaphysicians that they just make it up.
Related Idea
Idea 19400 Possibles demand existence, so as many of them as possible must actually exist [Leibniz]