The Christian can challenge the non-Christian approach to interpreting human experience "only if he shows the non-Christian that even in his virtual negation of God, he is still really presupposing God.” He puts the point succinctly in saying: "Anti-theism presupposes theism.” The intellectual achievements of the unbeliever are possible only because he is "borrowing, without recognizing it, the Christian ideas of creation and providence." The non-Christian thus "makes positive contributions to science in spite of his principles" because he is inconsistent.

The first objection that suggests itself may be expressed in the rhetorical question "Do you mean to assert that non-Christians do not discover truth by the methods they employ?" The reply is that we mean nothing so absurd as that. The implication is that non-Christians are never able and therefore never do employ their own method consistently.... The best and only possible proof for the existence of God is that his existence is required for the uniformity of nature and for the coherence of all things in the world.... Thus there is absolutely certain proof for the existence of God and the truth of Christian theism. Even non-Christians presuppose its truth while they verbally reject it. They need to presuppose the truth of Christian theism in order to account for their own accomplishments.

The sense of deity on the basis of Paul’s doctrine in Romans 1 provides us with an account of how those who disclaim any belief in God can know much about most subjects. The knowledge of God which every man has as the image of God and as surrounded by God's clear revelation assures us, then, that all men are in contact with the truth. Not even sin in its most devastating expressions can remove this knowledge, for "sin would not be sin except for this ineradicable knowledge of God.” It is this knowledge of God that all men have in common that guarantees that every man can contribute to the progress of science, and that some measure of unity in that task can exist between believers and unbelievers.

The apostle Paul speaks of the natural man as actually possessing the knowledge of God (Rom. 1:19-21). The greatness of his sin lies precisely in the fact that "when they knew God, they glorified him not as God." No man can escape knowing God. It is indelibly involved in his awareness of anything whatsoever.... We have at once to add Paul's further instruction to the effect that all men, due to the sin within them, always and in all relationships seek to "suppress" this knowledge of God (Rom.1:18).... Deep down in his mind every man knows that he is the creature of God and responsible to God. Every man, at bottom, knows that he is a covenant breaker. But every man acts and talks as though this were not so.

Unbelievers have faith as well as believers. But that is due to the fact that they too are creatures of God. Faith therefore always has content. It is against the content of faith as belief in God that man has become an unbeliever. As such he tries to suppress the content of his original faith.... And thus there is no foundation for man's knowledge of himself or of the world at all.... When this faith turns into unbelief this unbelief cannot succeed in suppressing fully the original faith in God. Man as man is inherently and inescapably a believer in God. Thus he can contribute to true knowledge in the universe.

Since self-consciousness presupposes God-consciousness there are no real atheists, only some that make a false profession. Unbelievers are suppressing what they believe about God the Creator. Self-deception involves deception of the self, by the self, about the self, and for the sake of the self. The analysis of self-deception in terms of iterated beliefs, corrigible disavowals, motivated rationalization of evidence, and self-covering intentions can help us better appreciate what Paul says in Romans 1, namely, that "knowing God," all men "suppress the truth in unrighteousness" and that unbelievers culpably deceive themselves about their Maker.

All men know and hence believe that God exists. The revelational evidence is so plain that nobody can avoid holding the conviction that God exists, even though they may never explicitly assent to this belief. We are justified in ascribing such a belief to men on the basis of their observed behavior in reasoning (e.g., relying on the uniformity of nature), in morals (e.g., holding to ethical absolutes in some fashion), and in emotion (e.g., fearing death). Nevertheless, all men are motivated in unrighteousness and by fear of judgment to ignore, hide, and disavow any belief in the living and true God, either through atheism or false religiosity.