He who makes a claim bears a burden to demonstrate the truth of his claim. Theists have a burden to demonstrate their claim that God exists, and atheists have a burden to demonstrate their claim that God does not exist. Nowadays, however, it’s common for atheists to claim that the theist alone bears a burden of justification. They try to escape their own burden of justification by redefining atheism from a “belief that God does not exist” to “the absence of belief in God.” Since only positive beliefs can be defended, they are off the hook. All the pressure lies with the theist.
While I think their attempt to redefine atheism is intellectually dishonest, let’s grant the validity of their redefinition for a moment. Greg Koukl observed that while it’s certainly true atheists lack a belief in God, they don’t lack beliefs about God. When it comes to the truth of any given proposition, one only has three logical options: affirm it, deny it, withhold judgment (due to ignorance or the inability to weigh competing evidences). As applied to the proposition “God exists,” those who affirm the truth of this proposition are called theists, those who deny it are called atheists, and those who withhold judgment are called agnostics. Only agnostics, who have not formed a belief, lack a burden to demonstrate the truth of their position.
Are those who want to define atheism as a lack of belief in God devoid of beliefs about God? Almost never! They have a belief regarding God’s existence, and that belief is that God’s existence is improbable or impossible. While they may not be certain of this belief (certainty is not required), they have certainly made a judgment. They are not intellectually neutral. At the very least, they believe God’s existence is more improbable than probable, and thus they bear a burden to demonstrate why God’s existence is improbable.
So long as the new brand of atheists have formed a belief regarding the truth or falsity of the proposition “God exists,” then they have beliefs about God, and must defend that belief even if atheism is defined as the lack of belief in God.