Even within what seem like black-and-white issues of religious or nonreligious, God or no God, there are subtle differences in the way we believe. In 2015, Pew reported that 89 percent of Americans believe in God, and 63 percent feel certain that God exists — which is to say, they don't harbor doubt about whether there is a God. (The share of people who say they are certain of God's existence has dropped; it was 71 percent in 2007.) The same survey found that 97 percent of religiously affiliated Americans believe in God, meaning a curious 3 percent of self-identified religious people do not. So although I, the atheist, can't stop myself from tossing up the occasional prayer, someone is out there kneeling in a pew, head bowed but mind free from any thought of a higher being. They do say faith is mysterious.