Jean Paul Sartre writes in Existentialism is a Humanism that "Existentialism is nothing else but an attempt to draw the full conclusion from a consistently atheistic position." For Sartre and like-minded thinkers existentialism is necessarily atheistic and there is much that follows from this, not the least of which is the conclusion that man is forlorn, abandoned, alone in a world which is incompatible with his deepest yearnings and needs. In a word, the world is absurd and life is meaningless. I've discussed this consequence in several places on Viewpoint (see, for instance, In the Absence of God and Grounding Human Rights).
There is another strand of existentialist thinking, however, which goes back to Kierkegaard, Pascal, even to Augustine, emerging out of the Christian worldview of these thinkers.
Like the atheistic existentialism of Nietzsche, Sartre, and others, it places a strong emphasis on man's subjectivity, that is upon his feelings, intuitions, emotions, and experience. Christian existentialism, no less than the atheistic variety, elevates the heart over the head, the realm of interior experience over the coldly rational, objective, and logical. Like his atheistic colleagues the Christian existentialist considers the preeminence of the subjective to be the essential characteristic of an existential approach to life, but in contrast to his skeptical friends he couples subjectivity to a belief in God. Indeed, belief in God is seen as the paramount example of the triumph of the subjective over the dehumanization of the purely rational approach to life and the world.
In his book The Universe Next Door James Sire discusses some ways in which Christians who tend toward the existential in their thinking differ from Christians who do not. For Sire, Christian existentialism focuses on the personal and the relational. The non-existential is more impersonal and more oriented toward the rational. Sire applies this distinction to a number of aspects of Christian belief and compares the two approaches. Using Sire's work as a springboard but not confining ourselves to it, let's consider the following examples of the difference between what Sire calls depersonalized Christianity and personalized, or existential, Christianity as applied to various doctrines of faith and practice:
Sin: The depersonalized view sees sin as a breaking of a rule, like one of the commandments, whereas in the personalized, or existential view, sin is seen as a betrayal of a relationship. Sin is anything which harms, or would harm, oneself or another, and, as such, it damages and subverts our relationships to our fellow men and certainly to God, who requires of us that we love each other.
Repentance: The depersonalized view sees repentance as an admission of guilt, whereas the personalized approach sees it as a deep sorrow or anguish over our unfaithfulness to God or our betrayal of our obligation to love our fellow man.
Forgiveness: In the depersonalized view one is forgiven in much the same way that one is absolved of a traffic ticket, i.e. by simply paying the fine. One breaks the rule, is fined, and that's the end of it. In the existential view forgiveness is a restoration of a ruptured relationship that can only be accomplished with tears and embraces, whether literal or metaphorical.
Faith: For the non-existential Christian, faith is merely giving one's assent to a set of propositions, as in the recitation of the Apostle's Creed. For the existential Christian, however, faith is committing oneself to a person in a love-relationship. The difference between the two views is like the difference between signing a contract and falling in love. It's living moment by moment with the deep angst that comes from knowing that what one loves could be lost, that what one believes can never be made sure by reason, it can only be certified by the heart.
Christian Life: In the non-existential approach the Christian life is a matter of observing certain rules of behavior. For the Christian existentialist it is living for, and with, another person (i.e. God). It is immersing oneself in the other to the extent that the other is the entire purpose and focus of one's being. The difference between the two views is like the difference between being in a business partnership and being involved in a passionate romance.
The Authority of the Bible: In the existential approach the meaning of Scripture is determined by how it speaks to the individual reader. The significance of the text is different for different people, and all meanings or interpretations are equally valid because they're all subjectively discerned. In a non-existential approach to the Bible, the text is seen to have an objective meaning, or meanings, quite apart from any subjective impression it makes on the reader. In other words, the meaning of the text is to be discovered through proper hermeneutics and not simply by consulting our feelings and intuitions.
Many Christians are wary of existentialism because of the overt atheism of its twentieth century practitioners and because of what they see as a rather "squishy" view of Biblical interpretation, but there is much else about this view of life which resonates with the profound human desire for union with God. Augustine wrote that: "Thou hast made us for thyself, O Lord, and our hearts are restless till they find their rest in thee." Christian existentialism is a response to this deep yearning of the heart for a relationship with the God who has created us for himself.