How did Gottfried Wilhelm Leibniz distinguish necessary truths from contingent truths?

In his philosophy, Gottfried Wilhelm Leibniz distinguished between two types of truths to explain the nature of reality and logical necessity:12

• Truths of reason: These are necessary truths whose denial would involve a logical contradiction. They are grounded in the principle of contradiction and are considered true in all possible worlds.13
• Truths of fact: These are contingent truths that describe the actual world. Unlike truths of reason, their existence is not logically necessary; they could conceivably have been otherwise.1

Leibniz argued that the existence of these contingent truths depends on the free choice of God. To account for why the actual world exists rather than another, he employed the principle of sufficient reason, which asserts that there must be an adequate reason for the existence and nature of everything that could have failed to exist. Ultimately, he maintained that God, being omniscient and omnibenevolent, chose to actualize the "best of all possible worlds," providing the sufficient reason for the specific contingent facts of our reality.14