Unfortunately, in many of the recent discussions about atheism and God, a number of crucial distinctions have gotten blurred together. It has become common, especially for the critics of atheism, to conflate atheism, materialism, naturalism, evolution, and natural selection. Then, an objection to one of these positions is taken to undermine all of them. This would be a mistake since there are several distinct positions here that the atheist may or may not also accept. And much of the energy that has been expended to knock them down is wasted because several of them turn out to be compatible with theism. Let’s clarify:
Atheism—Simply put, an atheist is someone who does not believe in a god or gods. A person’s atheism is widewhen they deny the existence of all gods. We can describe someone as adopting a narrow atheism position when they deny the existence of a particular conception of god. So Christians are typically narrow atheists about Allah, for instance, or about Thor.
Negative atheism: The term atheism can be understood the way “atypical” or “asymmetrical” are. It can mean “simply lacking a belief in God.” People who have not reflected on the question, or who are not sure can be described as lacking an affirmative belief in God, so they can be characterized as negative atheists along with those who affirm that no God exists. This sense of the term is not typically distinguished; usually what people mean when they describe someone as “atheist” is that they are positive atheists—they believe that no God exists. For the most part, when I use the terms “atheist” or “atheism” in my blog, I mean, “positive atheism.”
Ontological naturalism-is the view that the only things that exist are those that are discovered by and investigated by scientific methods. This could means something like, “the totality is made up entirely of spatial-temporal objects,” where spatial-temporal objects is understood very broadly. One way ontological naturalism can be spelled out is in terms of causal closure. Everything that happens is brought about by a fully physical history that is discoverable by science. There are no spooky, supernatural, or non-natural entities or causes, or if there are, they will be understandable in scientific, natural terms. (See Naturalism in the Stanford Encyclopedia of Philosophy.)
Methodological Naturalism– is the view that the best, most effective, or only means of acquiring knowledge is through the methods of science, not through a priori or purely conceptual approaches. The study of spatial-temporal objects employing the principles of observation, hypothesis, and empirical disconfirmation is the only way for us to come to know the world, even for traditionally conceptual and philosophical problems. Some people hold that methodological naturalism is compatible with a ontological supernaturalism. That is, they insist that we can believe in, or there can exist, supernatural beings, such as God, even though we engage in empirical investigations where no such entities are evident. The big question for the theist who is also a methodological naturalist, of course, will be, “how is the knowledge of God obtained?” MN is typically viewed as an epistemological thesis—it’s about how to acquire knowledge—rather than a metaphysical view about the ultimate constituents of reality. (See Naturalism in the Stanford Encyclopedia of Philosophy.)
Materialism—is the view that all things are made of matter and nothing else. While materialism appears to overlap with naturalism, especially ontological naturalism, we should see it as an explicitly metaphysical thesis about the ultimatum constituents of reality, but not as much a view about what the best methods are for acquiring knowledge of that reality. Some of the Greeks, for instance, arrived at the materialism conclusion through a priori or more conceptual reasoning.
Eliminative materialism- is a position from the philosophy of mind. It is the “radical claim that our ordinary, common-sense understanding of the mind is deeply wrong and that some or all of the mental states posited by common-sense do not actually exist.” The eliminative materialist believes that with the expansion of our scientific inquiries, there are often concepts such as “demonic spirits,” or “celestial spheres,” that cease to find a place within our theories. Some terms, like “heat,” we keep, but only be radically revising what we think the ultimate physical constituents of heat are. Other terms are too embedded in an old model of reality to be effectively salvaged. The label applies primarily to a position about minds, but we can see the implications for God and many religious concepts.
Reductionism—complex systems and phenomena can be reduced and explained entirely in terms of their parts and their causal interactions. Reductionism in philosophy of mind can be contrasted with emergentism, or epiphenomenalism. According to these anti-reductionist views, mental states, qualia, consciousness or other phenomena are produced by physical processes, but they cannot be explained entirely in terms of them. For a variety of reasons, theists are often anti-reductionists, but reductionism itself as a thesis about explaining objects in nature is distinct from atheism.
Supernaturalism—is the denial of ontological naturalism. Not all things that exist are natural. There are some entities, forces, or phenomena that exist beyond the spatial-temporal world that science investigates.
Theism—the view that God exists. Typically, the God that is of most interest to atheists and people characterized as theists is the singular, all powerful, all knowing, all good, personal deity who is the central figure in the major western monotheistic religions.
Evolution—is change in objects over time. Stars, dialects, and political systems evolve. In biological species, change can be induced by many factors including but not limited to natural selection. The suspected asteroid collision that brought on the extinction of the dinosaurs was an evolutionary event, but the extinction was not due to natural selection.
Natural Selection—is a specific causal mechanism on Earth whereby species evolved over time. The reproduction of organisms yields heritable variations. Some of these variations render some organisms better able to survive than others. Those differences in survival rates produce differences in reproduction of those heritable traits in the next generation.
I won’t embark on an ambitious argumentative thesis at this point. In fact, I think that wide positive atheism, and some forms of ontological naturalism, eliminative materialism, reductionism, and evolution by natural selection are the most reasonable positions given what we know. But I want to emphasize that an objection to reductionism or to naturalism, by themselves, are not objections to atheism. Atheism (narrow, positive) is a view about the existence of God, nothing more, nothing less. That view is compatible with a number of other ontological and epistemological views. So it will not do to conflate these importantly different positions together and accept or reject them wholesale on the basis of a particular objection to one of them.