Gnostic adj. of or relating to knowledge (from gnōstos meaning 'known')
Agnostic adj. a person who believes that nothing is known on some topic, either at the present, or in principle
In the philosophy of religion and recent public debates over atheism, a distinction is made of the difference between believing in God (theism) and not believing in God (atheism), but a third option, agnosticism is often regarded as the equivocation or uncertainty about whether or not there is a God. In fact, agnosticism is the denial that the existence of a God can be known one way or the other, and that we should stick to the facts we do know. Agnostics reject gnosticism of either kind. In biology, there are similar matters to consider.