I believe (along with others) there can be no true atheism, regardless the sincerity of such a profession! Children are void of doubting God’s reality when addressed concerning it, and adults always know of it. This is “the light of men . . . which lighteth every man that cometh into the world (Jhn 1:4, 9). I believe the “light” here means that God “shews” us His reality in our conscience—via the material world: “For the wrath of God is revealed from heaven.” “Because what may be known of God is manifest in them, for God has shown it to them.” “Since the creation of the world His invisible attributes are clearly seen, being understood by the things that are made.” “Although they knew God, they did not glorify Him” (Rom 1:18, 19, 20, 21). “Even though they did not like to retain God in their knowledge” (v 28) “they are without excuse” (v 20). John Gill on John 1:9: “It is best therefore to understand these words of the light of nature, and reason, which Christ, as the word, and Creator and light of men, gives to every man that is born into the world; and which serves to detect the Quakers' notion of the light within, which every man has, and is no other than the light of a natural conscience; and shows how much men, even natural men, are obliged to Christ, and how great a person he is, and how deserving of praise, honor, and glory. The phrase, "every man that cometh into the world", is Jewish, and often to be met with in Rabbinical writings, and signifies all men that are born into the world.” Since everything we see gives us the undeniable (e.g. “clearly seen”) knowledge of God’s reality, knowing that God is real is not an issue of faith, but of knowledge! During their deliverance and travels many of God’s people knew He was real but chose not trust in Him (Heb 3:12, 18, 19; 4:2, 6, 11). James (partly in opposition to the polytheism of the Gentiles) wrote that if, “Thou believest that there is one God; thou doest well: the devils also believe, and tremble” (2:19). The phrase “doest well” is not in reference to doing good but to merely being accurate, right or correct. In this sense we are discussing believing about God, not believing in God. There is only one alternative when not trusting in God—“suppressing” the knowledge of Him (Rom 1:18)!