No other debate seems to generate as much antipathy and mutual condescension than that concerned with belief in a god. History is soaked in the martyrdom of believers, often when the groups are merely variations on a larger one. A real fear surrounds political rhetoric concerning declarations pitting one religious group against another. Certainly, many wars have been fought within that dynamic but it's fair to say that those are eclipsed in number by conflicts of sects within larger groups. The conflagration that is the Middle World, for instance, is not between Christianity and Islam but that of the sects of Islam. With that in mind, it is a blessing that the modern vocal debate between atheism and theism does not follow the same trend.
While violence does not typically follow this debate, similar levels of ignorance and condescension do. Much is said about how tribalism has a hand in this, pitting one group against another as we fulfill the human social propensity to separate ourselves into disparate groups. The difficulty here is tribalism doesn't necessitate conflict of any particular kind. We can no more stop identifying with groups than we can stop forming pictures from disparate data points, like seeing Jesus on a piece of toast or animals in cloud formations. What we can shift is what we do after such automatic tendencies, the "second-step" so to speak along a particular path. The first step doesn't necessitate a conclusion, only a trajectory. What we do after will far more determine where we end up.
Determining an end goal in any debate is an important variable in what behavior manifests along the way. If the goal is a collapse of the other person's position, then total war is often inevitable. Words such as "decimate" are bandied about. Unfortunately for those cheering on one side, the other side will use the same descriptive terms for the same debate. This is why the war metaphor loses its legitimacy. In a physical war, "decimation" is possible, there are physical objects that move from one state to another, from completion to destruction. This is difficult to determine when it comes to ideological debates because the fortresses of a person's individual mind are as clearly constructed. On the surface, a person's stated position can appear to boil down to a singular point and hold varying degrees of stability. Beneath that surface each belief is an amalgamation of beliefs, often predicated on a structure of viewing the world that is little acknowledged.
What Belief?
Let's explore the belief in "a god," not "God." It is egoistic hubris to think that your god is the only god. When asked "Do you believe in God?", the question is really "Do you believe in my God?" and the acceptable answers have already been pre-determined. What is being ignored in such questions is a host of other beliefs. I'll point out just two beliefs everyone holds whenever engaged in dialogue. One, each person must tacitly accept that their sensory capacities are functioning in a way that they can trust what is said by one is heard exactly or nearly so by the other. Two, both tacitly believe that these words serve as a means of describing, or close enough, a shared reality. Such beliefs appear so obvious that pointing them out seems absurd, yet it is because they are so "obvious" that further beliefs develop which are anything but helpful.
Let's take the belief that words describe a shared reality. As any experience of miscommunication that involves some iteration of "that's not what I meant" can attest, words may point to a shared reality but the potential object or meaning is far broader than what we had in mind. Imagine a chair and then ask someone to do the same, write a brief description, and then compare. The odds are the descriptions will hold some generic similarities and a great deal of variation. If such is the case for simple things like chairs, imagine what it may mean for a far more complex idea like justice, equality, forgiveness, and god. However, suppose the tacit belief that words describe a shared reality is simply accepted. In that case, the result is a further belief that what one says means only one thing, whether that be from the perspective of the speaker or listener.
There are few more contentious examples of this belief in monolithic meaning than that concerning "god." The fact is that the term has no intrinsic meaning, not even that of a general kind like the previous chair example. With a chair and other physical objects, there's an extra layer of data being accessed beyond that of the mental space known as imagination, namely an actual shared experience of interacting with a chair. With "god" all that exists is the mental space, there is no actual shared experience because there's no commonality outside of an internal construct. There's no way to externally verify that what two or more people are thinking is the same. What is possible in this scenario is the sharing of yet further word concepts and the approval or disapproval of their appropriation for "god."
An Empty Vessel
The result is "god" as an empty vessel, a hollowed-out term capable of being filled with anything a person desires. Unsurprisingly, the substance of the term is filled with each person's character qualities, desires, hopes, dreams, and socio-historical assumptions. This is why when confronted by a theist-believer, the question of "What god do you believe in?" should always be followed up by "How do you consider your fellow human being should be treated?" or other questions concerning ethics. To stop at the first question is to fall victim to the assumption of monolithic meaning. On the contrary, there is simply no "true" believer if such is understood as being a singularly accurate representation of adhering to a particular god.
What is being fought over between and within theistic ideological systems is empty space. The conflict here is not over who's god is better, but who gets to fill in space with their desires, aspirations, demands, etc. It is a war over emptiness, an absence that is as tiny as the supposed human soul and as large as the cosmos. This is no less true than when the atheist enters the party. There is nothing being added when this is done except yet another person's notion of what to fill that emptiness with. The only distinction between a theist and an atheist is the possible substance accrued to the term, with the theist removing all other potential substances than their own and the atheist removing the last of them.
Atheism vs Theism, combine "god", filled with nearly anything a person desires and the human tendency to view contrary opinion-holders as deficient in intellect or moral character, the result ends up being a collection of ignorance and contempt that often describes the dialogue between competing groups. To avoid this, first, acknowledge the emptiness of what is being fought over, then accept that a person's concept of "god" may be different than assumed. Move forward to what matters most in the practice of living: how we treat one another and the world. Forgoing this, we'll continue circling the emptiness being fought over only to eventually fall into that dark morass.