Here is a passage that I often return to, from the inaugural address of one of my presidential predecessors, Edward John Carnell:
Whoever meditates on the mystery of his own life will quickly realize why only God, the searcher of the secrets of the heart, can pass final judgment. We cannot judge what we have no access to. The self is a swirling conflict of fears, impulses, sentiments, interests, allergies, and foibles. It is a metaphysical given for which there is no easy rational explanation. Now, if we cannot unveil the mystery of our own motives and affections, how much less can we unveil the mystery in others?
Others have also focused on the mystery of self-knowledge. In one of his rare love-poems, Matthew Arnold wrote: “What heart knows another? Ah! Who knows his own?” And commenting on St. Paul’s “Who has known the mind of the Lord?,” Gregory of Nyssa observed: “For my part I also ask: Who has known his own mind? Those who think themselves capable of grasping the nature of God would do well to consider whether they have looked into themselves.”
Carnell’s application of this realization is the right one. The awareness of the difficulty of self-knowledge ought to inspire in each of us a good dose of humility. If we have a hard time getting clear about our own motives and desires, we ought to hang a little loose in speculating about the inner life of others.
Even a non-Calvinist Christian should be able to affirm what John Calvin argues in the opening sections of his Institutes: the knowledge of God and the knowledge of self are intimately connected. We can’t grasp the one without the other. More specifically, Calvin says, we get a sense of our own inner life only when we view it in the “mirror” of God’s law. And, needless to say, that lesson is not learned by a one-time glance in the mirror. We need to keep looking, and even so, the best we can hope for is that we will see ourselves in a glass darkly, until the Day comes when our vision will be aided by a perfect Light. Which means that for now, humility is a virtue that needs to be cultivated on a daily basis.