“In the beginning God…” (Genesis 1:1, NIV)
In grasping a proper concept of reality, the first piece is understanding that God exists. The Bible begins with an account of the creation of the world, but that creation account already presupposes the existence of God. In the beginning, He is already there, and He acts to bring the world into being.
God is, we may say, the necessary presupposition. He is the basis of all else, including our own self-consciousness and the fact that we inhabit a rational universe. To honestly doubt the existence of myself may be insanity, but to doubt the existence of God is nonsense—for that would be doubting the basis for sense at all. God is the presupposition of the ordered and rational world in which we do our thinking.
Contrary to the popular idea that religion is a subjective field of life, one that concerns psychology and morality but not reality, religion is an objective field that concerns reality on the most fundamental level. The Bible begins with being: the God who is, and the universe He creates.
One practical implication of this is that human culture is inescapably religious because a culture must ask—and answer—questions about the nature of reality. And a culture that embraces idols rather than the true and living God embraces wrong ideas about reality, and thus should expect chaos. But a culture (or sub-culture, or counter-culture) that embraces the true and living God has a consistent first foundation on which to build an ordered society—a society that makes accurate judgments about transcendent matters, questions of the true, the beautiful, and the good.
Religion is never purely private, because religion is foundational to understanding the world. And true religion begins with the one true God, who was in the beginning, who acts, who lives eternally, and who reigns over this His world.