If Atheists firmly believe their beliefs, then they must believe some other beginning of the universe. They must believe in a theory. Atheists either believe in this theory or they are religious. There is no "inbetween" or "not caring." Not caring is not the same as not believing. It is impossible to not believe in something simply because you dont care. That is "illogical" as one would say to Christians. That being said, any belief would either be a theory or religion. If it were a religion, you are not an Atheist. If it were a theory, such as the Big Bang for instance, then it is not "proved" true, but, rather, this theory is backed up by predictions, mathematics, "logic," etc. Most Atheists would say that it is "illogical" to not believe in that theory. That being said, take into account the superstring theory. The theory of higher dimensions. This is also a theory: it has never been proved wrong, has made predictions, and is "logical" according to our mathematics/science. According to this theory there are 6 higher dimensions than our known 4, 10 dimensions total. The multiverse theory is a small category in this theory. Every possible universe from every possible beginning to every possible ending, with and without every possible possibilty, Infinite possiblities. Now, this is such a theory as the Big Bang Theory, thus, illogical to not believe in this theory. Now, if there are infinite possiblities of everything, then a God does exist, A 10th dimensional figure. And not only this, but there is no evidence that our "logic" and "science" is true or that we are the "control group" universe. Thus, by believing in anything other than a religion you are creating a paradox either being a hippocrite, liar, or "illogical."