It is interesting that when all the dust has settled, many big-name Christian apologists return to this simple answer. They will say that in their personal experience, the existence of God seems intuitively obvious. Plantinga will say that he simply sees it to be apparent when he views a beautiful mountain vista. Craig will say that he believes in God, not because of his own powerful arguments, but because of the internal witness of the Holy Spirit. John Calvin wrote of the sensus divinitatis or “sense of divinity” that resides in every human. He claimed that even false religion was an evidence, as
they never could have succeeded in this, had the minds of men not been previously imbued with that uniform belief in God, from which, as from its seed, the religious propensity springs. … The most audacious despiser of God is most easily disturbed, trembling at the sound of a falling leaf. How so, unless in vindication of the divine majesty, which smites their consciences the more strongly the more they endeavor to flee from it. They all, indeed, look out for hiding-places where they may conceal themselves from the presence of the Lord, and again efface it from their mind; but after all their efforts they remain caught within the net. Though the conviction may occasionally seem to vanish for a moment, it immediately returns, and rushes in with new impetuosity, so that any interval of relief from the gnawing of conscience is not unlike the slumber of the intoxicated or the insane, who have no quiet rest in sleep, but are continually haunted with dire horrific dreams. Even the wicked themselves, therefore, are an example of the fact that some idea of God always exists in every human mind.1
While not everyone claims to have this experience, it is worth considering. Why is human history filled with religion? Why are we so predisposed to believe in the invisible? Richard Dawkins argues that it is the evolutionary training of our brains that leads us to see gods in the heavens and fairies in the grass. Have all humans been so easily and completely deceived, only to be saved from their delusion by the modern skeptic who finally understands the truth?
If humans have a “sense” of the divine or an inexplicable desire for religion, then this feature of human history is easily explained by classical theism. Humanity has a God-shaped hole in its heart. In the absence of God, this feature remains a mystery.
However, this internal sense is not the only proof that could be offered from experience. There is also such a thing as shared experience, or better stated, the living testimony of the life of faith shown to us by the community of believers.
Theologian Karl Barth wrote, “Theology had first to renounce all apologetics or external guarantees of its position within the environment of other sciences, for it will always stand on the firmest ground when it simply acts according to the law of its own being.”2 Many authors have taken this notion and run quickly and passionately away from all classical Christian apologetics. However, this need not be the only interpretation of Barth. Instead, this challenge is a call to a more holistic apologetic, one where natural theology and philosophical studies are seen as neither preeminent nor meaningless.
Paul writes, “We destroy arguments and every lofty opinion raised against the knowledge of God, and take every thought captive to obey Christ” (2 Corinthians 10:5). The notion of “thought” surely extends beyond the raw intellect and into the emotive and the creative components of humanity. The success of Christianity has long been understood in this way, as an apologetic both of thought and of will, powerfully combining intellectually stimulating argument with heart-rending acts of self-sacrifice. Stackhouse calls this second component “corollary apologetics” and then states,
Since the Christian message fundamentally is an invitation extended to human beings (not just human brains) to encounter and embrace the person of Jesus Christ (rather than merely to adopt a doctrinal system or ideology) it is then obvious that establishing the plausibility and credibility of that message will depend upon more than intellectual argument. It will depend instead upon the Holy Spirit of God shining out through all the lamps of good works we can raise to the glory of our Father in heaven.3
It may very well be that the missing piece in the pursuit of God is found in the unrivaled conduct of the Church. This moves the conflict from the realm of philosophy to the practical world of congregational life. If the Church cannot complete the unfinished task of apologetics with the communal imitation of Christ Jesus, then Christianity has no right to expect conversions in the first place. In the material world of real people and real problems, it is the reality of God incarnate in Christ and Christ incarnate in his church that steers humanity from many possible rationalities to the true and living God.