1. The doctrine that certainty about first
principles or absolute truth is unattainable and that only perceptual
phenomena are objects of exact knowledge.
2. The belief that there can be no proof either that God exists or that God does not exist.
No human has been able to prove without a doubt either the existence or the non-existence of the supernatural. I'm not saying we cannot be spiritual. I'm also not saying there isn't more to life than the observable. But to confuse faith and religion with truth is just silly and indefensible. The truth is we can't know such matters and anyone who pretends to is making shit up.
When it comes to religion, we are all Agnostics, whether we acknowledge it or not.