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.

The core meaning of agnostic is a refusal to take either of the two main positions on the existence of God. The agnostic neither believes in God, nor denies that He exists.

Atheism

The term atheism is often used to mean denial of God's existence. For example, "John Doe says that God does not exist."

The same term is also used in as an umbrella term which combines or includes both the atheist position and the agnostic position. "Mary Roe says that she doesn't believe in God." This can mean either that she completely denies God's existence, or that she simply is unsure whether He exists or not.

The imprecision of the umbrella term leads to many long and pointless debates where advocates argue at cross purposes because the do not agree on the meaning of terms.

Agnosticism

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.

Preferences

Sometimes an atheist (i.e., a disbeliever) may prefer to describe himself as an agnostic to avoid giving offense or to avoid receiving adverse treatment. While this may be useful in social situations, it can lead to difficulties when describing someone's precise position.

Conclusion

There is a difference between saying I do not know and saying I do not believe and saying It is false.

The usage of agnosticism varies between saying, "God may or may not exist"; "There is no way to know whether God exists or not"; and "I do not believe in God".

All usages of atheism are consistent with saying, "God does not exist."