Implicit and explicit atheism

I shall understand by "atheism" a critique and a denial of the major claims of all varieties of theism.

[...] atheism is not to be identified with sheer unbelief, or with disbelief in some particular creed of a religious group.

Thus, a child who has received no religious instruction and has never heard about God, is not an atheist – for he is not denying any theistic claims.

Part of the reason, I suspect, lies in the chasm separating freethinkers and academic philosophers.

(see Smith (1990, Chapter 3, p. 51–60[4]))Everitt (2004) makes the point that professional philosophers are more interested in the grounds for giving or withholding assent to propositions: We need to distinguish between a biographical or sociological enquiry into why some people have believed or disbelieved in God, and an epistemological enquiry into whether there are any good reasons for either belief or unbelief... We are interested in the question of what good reasons there are for or against God's existence, and no light is thrown on that question by discovering people who hold their beliefs without having good reasons for them.

[5] So, sometimes in philosophy (Flew, Martin and Nagel notwithstanding), only the explicit "denial of theistic belief" is examined, rather than the broader, implicit subject of atheism.