One very natural dividing line that—for better or worse—is often used to distinguish those who believe in God from those who do not is that between theism and atheism, where ‘theism’ is used to mark the believers and ‘atheism’ the non-believers. Such contrastive labels can serve many practical functions even when the terms in question are not clearly defined. Individuals are often, on the basis of their beliefs and values, attracted toward one such label more so than the other. However, (...) once a clear statement of the substantive difference between theism and atheism is requested, things become more complicated, much more so than our casual use of these terms would suggest. What exactly is the best way to capture the relationship between theism and atheism? To what extent are they opposed to one another, and relatedly, to what extent should they be regarded as exhausting the available theoretical options? §2 will canvass a range of responses to this cluster of questions. In §3, we explore the social-epistemic dimension of the atheism/theism divide, by focusing in particular on the issue of religious disagreements, including those disagreements that take very different assumptions as starting points. (shrink)