One of my many joys of being a pediatrician is that I am involved in care and nurture of identical twins and triples. These children of multiple pregnancies are becoming more common because of infertility treatments. Advances in medical technologies has offered previously infertile couples the joys of parenthood. My challenge after their discharge from hospital and is brought to my clinic for review is to tell them apart. They are identical in every way. Sometimes, the parents sheepishly confess to me that they too have difficulty telling them apart! However, as they grow up, I slowly discover that I am able to tell them apart even though they are still identical in appearance. Initially it was the way they respond to others but gradually other telltale signs appear that mark their individual distinct personalities. It is a testimony to God’s creativity that each individual is unique with their unique personality. After making us, he threw away the molds. Thus the psalmist can echo that we are “fearfully and wonderfully” made (Psalm 139:14). Each person’s personality is as distinctive as their fingerprints or retina patterns. Though personalities are distinctive, they may be categorized into certain categories as people are also may be categorized according to ethnic origins, gender, or body shapes.
Carl Jung, a Swiss psychiatrist, published his book Psychological Types in 1923. In his book, Jung developed his observations that people are born with specific ‘preference’ which forms the foundation of his personality theory. Our personality are our preference that affect the way we perceive the world, receive information from the world around us, process the information and from it develop our responses which is acted out in our actions and behavior. This is what made each of us unique. We act on our level of preferences on an unconscious level and these preferences are well developed because it help us to live and cope with the complex world in which we live in with minimal stress. We because uncomfortable when we are forced to act outside our preferences.
Two people going into a building will notice different things, two persons having a conversation may remember different things and two persons listening to a sermon may respond in different ways. The principal reason for this, according to Jung, is that our preferences are born with us. Thus each of us have a distinct personality type. The procedure of determining the type of personality someone has is termed personality profiling. This does not mean we are robots and are not free to choose. We are free to choose but are likely to choose in a certain way because of our inborn preferences.

Knowing our personality will help us to understand ourselves. Knowing ourselves is part of the process of knowing God. Augustine of Hippo, one of the greatest theologian of the early church prays in his book, Confessions: “Lord, let me know myself; let me know you.” The Confessions may one of the earliest spiritual autobiography available and is still relevant today for its honesty and frankness. In his prayer, Augustine reveals his understanding that we need to know ourselves in order that we can know God. This is often referred to as the doctrine of double knowledge: knowing the lord and knowing ourselves. This is the basis of spiritual growth and theology. Reformer John Calvin uses this theme in The Institutes of the Christian Religion. Both Augustine and Calvin and many others realize that we need to know ourselves as a basis of knowing God. Knowing ourselves means moving beyond the falseness of our false self to the real self within. We are all born with our real self. However, as we grow older, we tend to develop a false self to meet the expectations of others, and to protect our real self. In time this become the self we show to the outside world. Often the false self is very different from our real self. 
Self-knowledge in the double knowledge doctrine involves discovering our real self. C.S. Lewis illustrate this process by an allegory in his book, Till We Have Faces. He retold the Ancient Greek myth of Cupid and Psyche from the perspective of Orual, the ugly half-sister of beautiful Psyche. Orual was so ugly that she hid herself behind a veil all the time. When Pysche was offered to the ‘God of the Mountain’ who was Cupid, Orural caused her to be banished by convincing her to lift the God’s veil which was forbidden. Later she came to repent her actions because of her jealousy and ignorance. Orual said,“How can [the gods] meet us face to face till we have faces?” Lewis argues that we have to speak with our own voices (not other’s), live our own desires (not other’s) and face the world with our own faces (not behind a mask). To do that we have to recognize our own voices and desires and have the courage to be transparent. In other words, to know our own unique personality which is one half of the double knowledge.

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