Agnosticism (from the Greek a, meaning "without", and gnosticism or gnosis, meaning "knowledge") is the philosophical view that the truth value of certain claims—particularly metaphysical claims regarding theology, afterlife or the existence of God, gods, deities, or even ultimate reality—is unknown or, depending on the form of agnosticism, inherently unknowable due to the nature of subjective experience. In western laypersons terms, an Agnostic is one who doesn't believe you can prove there's a God, but doesn't deny it's possible a God may exist.