Image via WikipediaFor a variety of reasons, some Christians erroneously insist that atheism entails absolute certainty that no gods exist. They attempt to paint atheists as irrational or demand that we somehow prove that there aren't any gods. This reflects either a misconception about the meaning of atheism or another less innocent motive. In fact, atheism does not require any particular level of certainty. All it requires is the failure to affirm belief in some sort of god(s).
Consider each of the following two questions for a moment, and notice the important difference between them?
- Do you believe in some sort of god or gods?
- Are you absolutely certain of your answer to question #1 to the degree that you have no doubt whatsoever that your answer is correct?
By definition, a theist is someone who believes in some sort of god or gods. That is, one must answer question #1 in the affirmative in order to be a theist. And yes, anyone who affirms question #1 is a theist. This is why atheists ask theists for evidence of their god(s). The theist is making a positive claim that something exists, and so the atheist is inquiring about the evidence to support this claim.
An atheist is someone who does not believe in any sort of god(s). One who fails to affirm question #1 is, by definition, an atheist. Again, if you do not believe in some sort of god(s), you are an atheist.
Question #2 is relevant in the sense that it contributes information about one's level of confidence, but it is not necessary in order to classify someone as theist or atheist. And as we know, one's confidence in any particular belief is not a valid indicator of the truth of that belief.
And so one is a theist if one answers "yes" to question #1 regardless of how one answers question #2. Some theists do profess quite a bit of certainty; others report considerable uncertainty. Doing so does not make them any more or less of a theist, although we might call a theist who is very low on certainty an "agnostic theist."
Likewise, those who do not answer "yes" to question #1 are atheists, regardless of how they answer question #2. That is, atheism does not require any particular level of certainty. An atheist reporting low certainty might be called an "agnostic atheist," but that does not make him or her any less of an atheist.
We would not say that a Christian who experiences some doubts about her faith is suddenly no longer a Christian because she does not claim to be 100% certain. In the same way, an atheist who is not 100% certain (or uncertain, if you prefer) does not magically stop being an atheist.