On the Fourfold Root of the Principle of Sufficient...

It was Leibnitz who first formally stated the Principle of Sufficient Reason as a main principle of all knowledge and of all science. He proclaims it very pompously in various passages of his works, giving himself great airs, as though he had been the first to invent it; yet all he finds to say about it is, that everything must have a sufficient reason for being as it is, and not otherwise: and this the world had probably found out before him. True, he makes casual allusions to the distinction between its two chief significations, without, however, laying any particular stress upon it, or explaining it clearly anywhere else. The principal reference to it is in his "Principia Philosophiæ," § 32, and a little more satisfactorily in the French version, entitled "Monadologie": En vertu du principe de la raison suffisante, nous considérons qu'aucun fait ne sauroit se trouver vrai ou existant, aucune énonciation véritable, sans qu'il y ait une raison suffisante, pourquoi il en soit ainsi et non pas autrement.[40]