I just finished reading an interesting piece in Slate by Ron Rosenbaum on agnosticism. It tapped into something that I think is a logical challenge of being a religious believer: namely, that the only way you can be 100% sure your faith is right is to be in some way delusional. Faith is almost meaningless if it ia guaranteed.
Does that make me a religious agnostic? (Or a Catholic agnostic, to be more specific?) I do think the medieval Church would have condemned this line of thinking, but I am not sure the Church of John Paul II, and now Pope Benedict, would. How can one say that religious belief cannot be compelled, acknowledge the legitimacy (if not the truth) of other traditions, and then state that a member of the Church must profess 100% certainty in all of its teachings? To believe is not to know.
And to go further, I think there is a good, theological reason we cannot be absolutely sure of our faith claims, one that has been said many times: to make God undeniable is to remove the free will which is His greatest gift to us. Even within an individual heart, an unearned certainty in one's faith turns the believer from a free soul to an automaton. And history shows that those who are absolutely certain in a belief, whether in the Catholic Church, or Islam, or Communism, or Atheism, or the superiority of a certain race, are likely to do horrible things in the furtherance of their beliefs.
There are few humans so incurious about the world that the question of why we are here will never come to them. And that sliver of a non-materialistic question opens the door to belief. As the compulsion to believe fades from human society, I think religion will get more confused and less hierarchical, but the need people have to 'grow in faith' together (a process more halting and unsteady than the phrase implies) will remain. There will be a purges and renewals in faith, as has happened periodically throughout the history of all the great religions, but the existance of doubt does not destroy, and may increase, the need for organized churches.