Strong agnosticism or positive agnosticism is the belief that it is impossible for humans to know whether or not any God or gods exist.
Weak agnosticism states that the existence of any gods is simply unknown, but is not necessarily unknowable. Neither type of agnosticism is irreconcilable with theism (belief in a deity or deities) since one can have faith in the existence of a deity without necessarily claiming knowledge of it. Both types can also be reconciled with strong atheism for the same reason, though this can be disputed depending on how one defines both "belief" and "knowledge". Weak agnosticism often overlaps with, and is often confused with, weak atheism, as both are a lack of belief rather than a belief in lack (of either existence or knowledge).
One criticism of strong agnosticism is that it denies the ability of gods to prove their existence.
See also