Atheism and agnosticism are commonly misrepresented as two stances that can not be held simultaneously, or that agnosticism is a less convicted position of atheism. The truth is that atheism and agnosticism are not mutually exclusive. A theist can be agnostic, and an atheist can be a gnostic.
Theism/Atheism addresses the question of belief. Theism is the belief in a god or gods. Atheism (weak/soft/negative atheism) is the default atheism, and is the lack of belief in a god or gods. The theist, one that believes there is a god, is claiming that a god exists. This person has the burden of proof. The atheist is one who rejects that claim, without making a claim of their own. Because of this, there is no burden of proof on the atheist to disprove god.
Gnosticism/Agnosticism addresses the question of knowledge. Gnostics know that ‘x’ exists. Agnostics do not claim to know that ‘x’ exists.
An example of how non-mutual exclusivity works in this context is the agnostic theist. A person who believes that god exists, but admits that they can not know for certain that god exists.
Generally, people are agnostic in regard to claims of the supernatural. It is more common still for an atheist to be agnostic in regard to claims of a deity.
- hard/positive/strong atheism – the assertion that no gods exists. This position, having stated a claim, necessarily has the burden of proof.
- anti-theism – the belief that theism and religion are harmfully impactful.
- polytheism – the belief in many gods.
- pantheism – the belief that the universe is god.
- deism – the belief in a non-personal or non-interacting creator.
Atheism, being a lack of belief, is necessarily the default position. This can be made clear when you consider the fact that one can not believe things that are as yet unthought of by one’s mind. To all of these un-postulations, we remain necessarily in the position of withheld belief. By this logic, all humans are born atheists. At some point after birth, children will most likely be exposed to ideas of a god or gods, and they may not accept these claims, remaining atheists, or they will believe these claims and convert to theists.