Atheists are constantly told that atheism is a belief, it should be simple then for people to tell Atheists what it is that they all believe in. So here is the challenge. What do all Atheists believe in? I am not interested in what we do not believe in, only in what we do, can anybody state what Atheists all believe in? To help we will use the oxford dictionary definition of belief. An acceptance that something exists or is true, especially one without proof. ‘his belief in extraterrestrial life’ with clause ‘a belief that climate can be modified beneficially’ 1.1 Something one accepts as true or real; a firmly held opinion. ‘we're prepared to fight for our beliefs’ mass noun ‘contrary to popular belief existing safety regulations were adequate’ 1.2 A religious conviction. ‘Christian beliefs’ mass noun ‘the medieval system of fervent religious belief’ https://en.oxforddictionaries.com/definition/belief
Mathematically, the answer is the null set: https://en.wikipedia.org/wiki/Null_set Suppose is a subset of the real line such that where the Un are intervals and |U| is the length of U, then A is a null set. Also known as a set of zero-content.
Interesting I have to admit a lack of knowledge with regard to linking the null set to Atheism, and the idea has certainly interested me. However I would argue that only those Atheists who have considered the idea actually believe in it, many many atheists do not believe like me simply out of ignorance of the null set.