From Unofficial Handbook of the Virtue Universe
Agnosticism is the view that the truth value of certain claims—especially claims about the existence or non-existence of any deity, but also other religious and metaphysical claims—is unknown or unknowable. Agnosticism can be defined in various ways, and is sometimes used to indicate doubt or a skeptical approach to questions. In some senses, agnosticism is a stance about the similarities or differences between belief and knowledge, rather than about any specific claim or belief.
Others believe more literally in the definition of Agnostic as "(from Ancient Greek ἀ- (a-), meaning "without", and γνῶσις (gnōsis), meaning "knowledge")" or belief only with evidence, specifically scientific evidence.