From an article at The Clear Lens
If the term “atheism” simply describes a missing mental property (i.e. a lack of belief), then the definition is too broad to be meaningful. Given this new definition there would be no difference between an atheist and the armchair he’s sitting on; that is, an armchair also lacks a belief in God just like the atheist.
If the term “atheism” simply describes a lack of belief, then there can be no argument to support what is lacking. It is merely describing an absence of an opinion. Atheists, therefore, cannot support absence with any good reasons; for, in absence, there is nothing to support. This relegates their view to the same level of seriousness as an aversion to lima beans or boiled cauliflower.
If the term “atheism” simply describes a lack of belief, then atheists like Richard Dawkins, Sam Harris, and Christopher Hitchens went to an awful lot of trouble writing books describing their missing mental property. As a matter of fact, I’m curious how the internet atheist should interpret Dawkins’ chapter title in The God Delusion: “Why There Almost Certainly is No God”. Perhaps he should read it as: “How My Lack of Belief Explains Why There is No God”.
The point is: atheism is not a mental property nor does it describe someone’s psychology. Atheism is a proposition or a truth claim about the world; and that proposition is: God does not exist. The only way Dawkins, Harris, Hitchens, and others can make arguments for their view is if they actually have a view to begin with. As William Lane Craig and J.P. Moreland point out, “[A] redefinition of the word atheist trivializes the claim of the presumption of atheism, for on this definition, atheism ceases to be a view…”