Agnosticism in its formal aception is that God, if exists, cannot be known. A more modern and prosaic notion is: "I can't decide if God exists or not". Absentheism leaves open the possibility that a deity exists and can be known. Or doesn't exist. Or exists and cannot be known. What is saying simply is this: God's presence can't be attested here and now. (hence, the term "absence" because the possibility of presence also exists), and that's all we can say about deity that can be demonstrated without resorting to grandiose claims about the existence or non-existence of deities.
Eden