 The principle of piety is “to live honorably.”  An important difference between strict right and equity, on the one hand, and piety, on the other, is that the former pertain to our pursuit of goods and avoidance of evils over the course of our natural lives while the latter pertains to our pursuit of goods and avoidance of evils throughout our entire lives, that is, over the whole course of our immortal existence. The third grade of justice thus relies on two central tenets of Leibniz's metaphysics, for which he believes there are demonstrative proofs; indeed, he believes he provides such proofs (PE, “Principles of Nature and Grace, Based on Reason,” §4, §8; PE, “Monadology,” §4, §38). The tenets on which this account relies are (1) that the soul is immortal and (2) that God is the ruler of the universe. Most relevant to our purpose are not the arguments he supplies in support of these but, rather, the work that the theses do in his account of piety.