Definitions of Atheist and Agnostic

It is difficult to define terms such as Atheist and Agnostic, because various people use them differently. The core meaning of atheism is the denial that God exists. Some argue against God's existence on the grounds that they have a satisfactory disproof; see Strong atheism. Others argue againsts His existence on the grounds that believers do not have a satisfactory proof; see Weak atheism.

Some writers use the term agnostic in the general sense of being undecided. For example, "Smith isn't sure whether God exists or not." Others add to this a specific reason for being undecided, which elevates the position to the following argument:

1. Jones sees no way to prove or disprove God's existence
2. Therefore, Jones is undecided.

Interestingly, the lack of a satisfactory proof is interpreted two different ways. Weak atheism uses this as grounds for denial. Agnosticism uses this is grounds for refusing to commit one way or another.