Beyond a doubt, the most significant question to ever penetrate the human mind is that of the existence of God. More consequences for humanity hinge on the denial or affirmation of God's existence than any other issue.
Countless numbers of Christian families have sent their children off to schools across America only to see them return as strangers robbed of their faith in God and of the basis for morality and ethics.
Many of these children have attempted to fill the vacuum in their lives through aberrant sex, drugs, and alcohol. Others have sought to fill this void with material success, which can never satisfy the spiritual needs of one created in the image of God.
"Is there really a God?" Though there are a variety of possible responses to this question, there are three traditional responses that predominate in Western society: (1) God does not exist — atheism; (2) we cannot know whether God exists — agnosticism; and (3) a personal God does exist — theism. This article will demonstrate how, in witnessing to an atheist, one can move from atheism to agnosticism, from agnosticism to theism, and from the concept of an impersonal God to the personal God of Scripture.
To begin, atheism involves a logical fallacy known as a universal negative. Simply stated, a person would have to be omniscient and omnipresent to be able to say "there is no God" from his own pool of knowledge. Only someone capable of being in all places at the same time — with a perfect knowledge of all that is in the universe — can make such a statement based on the facts. In other words, a person would have to be God to say there is no God. Hence, the assertion is logically indefensible.
By using arguments like this, you will often find that an atheist quickly converts to agnosticism and is thus making progress rapidly in the right direction.
This leads us to the second possible response: agnosticism. In dealing with an open-minded agnostic, an approach I have found effective is to point out that the universe is an effect which requires a sufficient cause, and the only sufficient cause is God. As Scripture says, "the heavens declare the glory of God; the skies proclaim the work of his hands" (Ps. 19:1).
It is helpful to clarify that there are only four possible explanations for how the universe came to be. The first is that the universe is an illusion. This ultimately reduces to solipsism — the theory that "self" is the only reality, that "I alone exist." This view is unacceptable in an age of scientific enlightenment. (Even a full-blown solipsist looks both ways before crossing the street.)
The second possibility is that the universe is eternal. This possibility flies in the face of the second law of thermodynamics, which says that everything in the universe is running inexorably downhill from order to disorder, from complexity to chaos. If the universe was eternally old, it would have died a heat-loss death an eternity ago.
The third "possibility" is that the universe emerged from nothing. Little needs to be said about the absurdity of this option. Reason tells us that out of nothing comes nothing. This position militates against the first law of thermodynamics, which says that energy can be neither created nor destroyed; it can only change forms. To say an effect can exist without a cause, one must deny the basis for all scientific investigation and rational thought.
The fourth (and only tenable) possibility is that the universe was created by God. Clearly, theism — the belief in a personal God who is the Creator and Ruler of the universe — is the only viable option on the question of God's existence. Once this is established, it can be pointed out that only a personal God can account for human personality, thought, and morality. Furthermore, this personal God has manifested Himself in the person of Jesus Christ, who demonstrated His deity through the undeniable fact of the Resurrection. Additionally, God has provided His written Word which can be shown to be divine rather than human in origin.
Although we cannot talk atheists and agnostics into the Kingdom of God, God can use our answers to open their hearts to receive the gospel. Scripture therefore exhorts us to "always be prepared to give to every man an answer" (1 Pet. 3:15).
(For further insight, my tape “Objections Overruled” and Personal Witness Training: Your Handle on the Great Commission are available from CRI.)