"Belief," as in "Do you believe in the existence of God?", is only an issue for the church (or Christianity) if the baseline is atheism: i.e., God cannot exist and cannot be "believed."
But most people are not atheists. If they are indifferent to the claims of Christianity (for which apparently "belief" is paramount), then they are equally indifferent to the claims of atheism. Both espouse the centrality of theistic thinking, one positively, one negatively; at least, that's the argument. And then it's just a matter of either/or, of who has the best argument. And besides adherents to the arguments, who's interested in that? Yes, there are people on the intertubes whose motivating purpose seems to be arguing about anything and everything, but especially politics. Even most politicians, however, don't go in to politics to argue (though that seems to be their raison d'être since at least the "Gingrich Revolution"); they to it to serve in government (or line their pockets, if you want to be cynical). There were once people who served in government to do what was right, generally. Two names come to mind from the Congress: Lyndon Johnson, in the Senate, and Sam Rayburn, in the House. Turns out they were instrumental in helping Hawaii become a state, by overcoming objections from Representatives and Senators from the South. Of course, they accomplished some other worthy goals, too.
They didn't do it because government was good or evil, was intrusive or exploitative, was a "deep state" or a "derp state." They didn't do it because government was either/or. Now, however, everything is either/or, to a pitched degree. It's not the kind that is different, it's the degree. There has always been a struggle between believers and non-believers; it's the degree of emphasis that's the issue.
Much as Christianity specifically has taken empiricism as the baseline for human understanding and epistemology (Christianity is on much sounder footing in Western philosophy connecting with phenomenology), so the discussion of religion in Western culture has taken atheism as the baseline, against which theism must assert its bona fides. That is completely the wrong argument. In fact, the problem is the diagnosis that an argument is what will "fix" the "problem" of the church. Contrary to what may be common experience, people don't go to church to argue; and solving the "argument" of atheism v. theism won't bring people flocking back to church as if this were the 1950's redux.
People go to church because church means something to them, and because they find people of like mind there, people they can be friends with. The Church of Meaning and Belonging can't get a foothold without the Church of Belonging existing first, and the Church of Belonging can't exist if people don't find people there they want to share time with. Then there is the question of how they share their time, and why they share their time.
But why did "belief" become the dividing line of our thinking? Why must we stand on one side or the other, with one side "wrong" and the other "right"?
Slate ran an interesting article about the "march for science," which turned on this concern:
Instead, the march revealed the glaring dissonance of opposing that trough of ignorance by instead accepting a cringe-worthy hive-mind mentality that celebrates Science as a vague but wonderful entity, what Richard Feynman called “cargo cult science.” There was an uncomfortable dronelike fealty to the concept—an oxymoronic faith that information presented and packaged to us as Science need not be further scrutinized before being smugly celebrated en masse. That is not intellectually rigorous thought—instead, it’s another kind of religion, and it is perhaps as terrifying as the thing it is trying to fight.
What the article argues for, ironically, is a more scholarly approach to knowledge, but does so in part by citing that Feynman article where the scientist relies on the hoariest of shibboleths (the "Middle Ages" were ignorant, then came the enlightened salvation of the Renaissance!) to make his point. Talk about "an uncomfortable drone like fealty to the concept." But that's that point, one drummed into me in seminary more than anywhere else in my education: what you cling to as certainty is your idol, your false god, your deity made in your image. It's a useful hermeneutic of suspicion to keep before one, because the either/or of belief (either you do ("fool!") or you don't ("wise!")), is just such a dead piece of silent, eyeless stone.
Jump to the end of the quote there, and "cargo cult" is connected with the broader non-science of Western culture: religion. Because religion is not "intellectually rigorous thought." Except, again, as I said, the most intellectually rigorous education I ever had was in seminary, where every assumption was challenged and no answers were given. I seriously doubt any student of any science had their assumptions, presumptions, and conclusions challenged as thoroughly as that. Even law school only challenged how I organized my thought and how I analyzed situations. Once I learned to "think like a lawyer," I had made it through the barrier between the laity and the learned. I left seminary knowing much more about the challenges than the certainties, much less inclined to "march" for religion than to consider the place of humans in the world they were busy making.
How many scientists are trained to think that way, trained to actually call in to question everything they have been told in lower-school science classes for decades is true? I don't mean the basic concept of science v., say, alchemy or astrology, but the conclusions of scientific research, of scientific thought, of accepted scientific theory. Not to question it because it is wrong, but to question it because you can't truly understand what you don't critically examine.
When it comes to belief, everybody just believes: that's the real foundation of modern Western philosophy. Not Descartes' cogito, but his conclusion that he had to rest his thought on his cogito: if he didn't accept something as a given, he couldn't establish anything. His ability to think escaped his hermeneutic skepticism only because, without that escape, all he had left was skepticism. You have to accept some givens in order to postulate a system. If you insist your ideas are not founded in a belief, then you are insisting it really is turtles all the way down. How many scientists study philosophy in order to understand empiricism, the philosophical basis of the scientific method? How many study phenomenology, or world religions, or even take a course in philosophy of religion? How many study formal logic, philosophy of science, the history of philosophy? And yet in my seminary studies I studied philosophy, history, absorbed information and thinking from anthropology and archaeology, studied languages and how language affects our understanding, our perceptions, our thinking; examined and developed hermeneutics, systems of interpretation and analysis. Do scientists study any of this? Or do they just study the field of science they are interested in?
That paper from Feynman about "cargo cults" doesn't display much more than a muddled, popular understanding of religion, history, and human culture. Anthropology is the scientific study of human culture, but what Feynman knows about that subject seems to be the pop culture notion of a "cargo cult" being one-for-one mapping of non-scientific, i.e., "religious," thought. Anthropologists wouldn't even engage that kind of discussion, because it is as ignorant as saying the planets are set in crystalline spheres rotating around the earth. I know this, Richard Feynman apparently doesn't; yet he is lionized for his "knowledge." Except, in certain areas, it should be spelled "nollij."
What's happening in modern American society is a dissolution of cultural bands that once held the center together. At least it seems that way, though I'm not so sure those bands were ever so strong or binding as we imagine. Most of us either remember the '50's, or take our starting point for American culture from there, and tacitly use it as our starting point for what we believe (v. what we know, in this context) about where we are now. I've quoted Eliot's "Choruses from 'The Rock'" time and again, about culture falling apart because of motor cars; words he wrote almost 100 years ago now. Cars mean nothing to us now, now it's cell phones and social media dividing us up. But, as Howland Owl said of nuclear physics, the situation ain't so new, and it ain't so clear.
We despise ambiguity; we want certainty. Many a scientist, or one scientifically trained, will outright reject or find reason to denigrate, Kuhn's ideas about science and "paradigms," because Kuhn introduces a conditional ambiguity into science. Similarly Schrodinger's cat tells us, not that the cat is neither dead nor alive, but that we can't predict with accuracy the reality of the state of the cat, we can only observe it by opening the box. The ambiguity is inherent in the position of not yet observing the contents of the rigged box. We want certainty, but the paradox of Schrodinger's thought experiment is that we can't have it without intervening (opening the box). Kuhn's ambiguity is that science is a human system, prompted and guided by human interests (and by the drunk under the streetlamp). But science must partake of the divine, the true, even if that "true" is the cosmos itself. We want to link our understanding of the cosmos to the cosmos so what we know what we know is "true."
We despise ambiguity; we want certainty. If I say I know God in my life, I'm immediately charged, or understood, as saying "God exists." We want that certainty because if God exists, then certain things must be true. But saying "God exists" is not the same thing as saying "A platypus exists." Surely it's odd to find a platypus in the wild, but the existence of the platypus means nothing to my life, to my culture, to my world. To say "God exists" is to say something entirely different than to say "My daughter exists," even though that statement has more meaning for me personally (and for her). I tend to agree with Tillich on this one: that the concept "existence" or "To exist" can't really be applied to a concept like "God" (and already someone will think I've slipped a card from the middle of the deck by using the term "concept," but it is the right term in this conversation). My father is dead, but does that mean my father doesn't exist? If by exist you mean "alive," then no, he doesn't exist. But his absence creates a presence that is still quite real for my mother, for my family, and the memories of him are no less real than they were when he was alive. Let's face it, most of what we know about friends and family is memory, especially as they grow older and move on. I have a large extended family I seldom see anymore, yet they exist for me even as more and more of them pass on. Not only in memory, but in me: I am who I am because of friends and family. I am my father's son, just as my daughter is his granddaughter. "Exist" goes far beyond a name etched into a headstone, or simply still drawing breath.
We want certainty, and we cheat to get it. God must "exist" as people do, as trees do, as platypi do; because that is existence as we know it. Except it isn't, of course; a tree I don't know about still exists, whether I know about it or not (unless you are a Berkeleyian, and I don't think there are many of those left around, though I would never say they don't exist!). But does a tree have existence?
Ambiguity is the heart and soul of thinking; which may be why we despise thinking so much. Thinking never leads to certainty; it only leads to more questions. So, ironically, to march for science is to march for uncertainty; and to not understand that is to abuse scientific reasoning as much as to declare certainty about God is to abuse Christianity. Am I certain about God? It is not a question I can answer, because it is not a valid question. I have faith in God, which is to say I have trust in God. Does that mean something to you? Perhaps no more than if I say I love my wife. I cannot prove that statement, but who asks me to? People said Bill Clinton could not love his wife, when he betrayed her trust so often and so publicly. People questioned how Hillary Clinton could love her husband, and in a simpler world perhaps they would have conformed to some expectations and divorced, or at least been publicly miserable about each other. They didn't, and we all had to realize whether or not they loved each other was not for our determination. No one asks if my love for my wife exists, but perhaps we could ask if it is true. Again, how would I prove it? I've known couples who loved each other even after their divorce, or without any benefit of marriage. Do such externals prove something that cannot otherwise be true? How do I establish that truth? If you say I cannot love my wife unless I prove it, my first question will be: what does "love" mean to you? If you say I cannot believe in God until I prove God's existence, I have two questions for you: what does the word "God" mean to you? And what is "existence"? Is it a property inherent in materiality, or a property of being?
You can see where this goes. We use language too loosely. We don't like to think about what we are saying, so busy are we to say it. Buckminster Fuller reportedly spent a year in silence, trying to recover the proper use of language. I'm not sure language is recovered in silence, so much as the use of it is discovered, perhaps even revealed (surely a revelation is at hand!) in usage. Rather like life itself; even the desert fathers lived in community, not in solitary isolation. If they had not contacted some other living soul, how would we know they were ever there?
Do I believe in God? I do. Do you understand what I mean by "believe" and "God"? Probably not. Do I communicate anything except confusion when I answer the question? Undoubtedly so.
Such is the ambiguity of the current situation.