A Theist is someone who believes in God or a god, an atheist is someone who lacks such belief. Is it that simple? Is Atheism simply a lack of belief? Obviously there must be more to it then that, since that would mean that dogs are atheists, and babies may or may not be atheists, but generally we those we call atheists are expected to at least consider the possibility of a Deity. So how about defining an atheist as someone who might otherwise believe in God, or a god, but lacks such belief for whatever reason, and nothing else.
The problem with such a definition is the nature of what God is and what reasons for God might be. Let’s say I simply lack a belief in—to use Bertrand Russell’s example—a teapot in orbit around the earth; that believe has almost no effect on other beliefs I may hold. Let’s say I believe a teapot is in orbit around the earth, and I find out later that this is not true, what have I lost? Nothing really. The fact or not of a teapot being in orbit around the earth doesn’t affect my moral worldview, doesn’t affect my cosmology, my ontology, my epistemology, my view of history or really anything. So I can say I simply lack a belief in a teapot in orbit around the earth and leave it at that, lacking belief doesn’t hold me to much of anything else.
There are beliefs that aren’t like this at all; so for example, let’s say I simply lack belief that Japan exists, I suddenly have a lot of things I have to explain. Why is it that Japan appears on all the maps? Where to Japanese people come from? What about people who claim to have visited Japan and so on and so forth.
Lacking belief in God, as opposed to simply “a god” is much more like the latter. The question of whether or not any small g “god” exists generally is just a question of whether a super powerful being happens to exist somewhere in the universe; however the question of whether “God” exists, i.e. the creator of all things, the ground of all being, and the source of all moral truth has much more at stake.
If you declare that there is no capital G “God,” immediately more questions arise. For example; what is the source of being? What is the cause of the universe? Is there such a thing as moral truth, or even truth at all? How could there be without a transcendent ground for moral truth or even truth itself?
Of course I’m not claiming the atheist must answer all of these questions necessarily, just as the guy who denies that Japan exists may not necessarily have to answer all the questions that come after he denies the existence of Japan. But what I am saying is that the atheist is making a claim that those questions are either meaningless, or they have plausible answers outside of theism.
For example, let’s talk the question of moral truth. The Atheist—in denying that he believes in God—is either tacitly claiming that there is no such thing as moral truth, or that there is such a thing as moral truth and it can plausibly be accounted for outside of theism, even if he himself doesn’t know how to account for it. If he is claiming the latter, he should be able to give what a possible accounting could be.
Shrugging your shoulders and saying “I don’t know” isn’t good enough, at least if you want to be considered rational. The Atheist would either have to give a possibility (true or not), or show why other problems with God’s existence outweigh this specific issue. If there is no, even possible, naturalistic explanation for moral truth, and yet the atheist doesn’t want to deny its reality; then the atheist is simply asserting his own refusal to think.
Nobody who is an atheist “simply lacks belief in God,” with that lack of belief comes the assertion, either explicitly or implicitly—of many other claims. For example: There is no moral truth or moral truth can be accounted for naturalistically, the universe has no transcendental source, being has no transcendental ground, that truth either does not exist or can be accounted for naturalistically. Or that there can be a transcendent ground and source for these things that would could not be, and differs significantly from, what theists mean when they say “God.”
These claims are being made whether atheists want to be held accountable for them or not. Don’t let an Atheist get away with the lazy and dishonest statement “I simply lack belief in God or gods, that’s it.”