So what is this atheism that upsets so many people? It is really just the refusal to believe in God because of the absence of sufficient reasons. It is a nonbelief—not something believed to be the case. Thus there can be atheists with a great variety of different outlooks on innumerable topics. They are all united on just one negative proposition—“I do not believe in God.”
Very little follows from this as far as metaphysics, epistemology, ethics, politics, aesthetics, or other disciplines are concerned. However, atheists do all decline to affirm the existence of God and closely related supernatural entities and events.
Another crucial (and controversial) issue related to atheism is whether rejecting belief in God implies anything at all about the world other than that it is completely natural and accessible to study by the means deployed in the sciences and in ordinary understanding. For example, does atheism imply materialism? Does it imply physicalism? Does it preclude mental entities such as minds, concepts, thoughts, etc.? Strictly construed, it does not. Nature could well contain a great variety of stuff; so as far as what exists in the world, atheism is open to whatever type and kind of existence is discovered to exist by rational means.
Furthermore, atheism does not imply anything about whether ethics is part of human life. That, too, must be left to be determined by means of science and other naturalist approaches by which human beings study the world. Some atheists are reductive materialists and altogether deny ethics because ethics presupposes choice, something on the order of free will. “Ought” implies “can,” so that if human beings have various ethical or moral, even political, responsibilities or obligations, it must be the case that they are free either to fulfill or to neglect them on their own initiative. This is precluded if nature is fully deterministic, as reductive materialism takes it to be. An emergent view of nature, however, whereby different types and kinds of beings can exist, not all reducible to just one sort, could make room for choices and, thus, for ethics and other normative realms.
This is also the case where mentality is concerned. Some hold that atheism implies that no minds, distinct from brains, can exist, but that, too, is wrong. Take, for example, the late best-selling Russian-born author Ayn Rand. She was an atheist but did not deny the existence of consciousness, specifically the mind. Whether the mind exists is something we could well discover about nature. The matter is not something we can settle a priori. If evidence shows the existence of different types and kinds of beings—for example, biological, chemical, mathematical, musical, or whatever there might be in the world, including minds, feelings, thoughts, abstractions, and so forth—that would be that. Atheism does not require rejection of any of these realms or reality. That must remain a matter of what the various sciences discover and identify.
A few years ago, two very prominent “new” atheists suggested that atheists might gather into a group, perhaps called “Brights.” A problem with this was that simply too many varieties of atheists are to be found, many of whom would be quite uncomfortable in the company of fellow atheists who hold drastically different philosophical, ethical, and political positions. Secular humanists, for example, tend to hold positions on matters other than whether there are reasons to believe that God exists. If they are atheists (some are agnostics), they are just one variety.
It appears, then, that atheism per se is best not overloaded with beliefs apart from the simple one of nonbelief in God’s existence. The rest is best left to what is discovered to exist—to be true and right and good.