The end of faith.

Agnostic –noun
1. a person who holds that the existence of the ultimate cause, as God, and the essential nature of things are unknown and unknowable, or that human knowledge is limited to experience.
2. a person who denies or doubts the possibility of ultimate knowledge in some area of study.

Atheist -noun
a person who denies or disbelieves the existence of a supreme being or beings.

Basically, according to the dictionary, atheists deny and/or don't believe in the existence of God. Agnostics simply say it cannot be proven one way or the other. You could say neither have religious faith, I suppose.

EDIT: For clarity's sake, I should say that neither have faith in a supreme being, rather than "religious faith." Because you can actually have religion without it being centered around a supreme being, as shown below (I love the dictionary.) It's only "especially when considered as the creation of a superhuman agency." But you can have a religion based upon something like the big bang theory, as well. Which is why scientology exists.
Religion –noun
1. a set of beliefs concerning the cause, nature, and purpose of the universe, esp. when considered as the creation of a superhuman agency or agencies, usually involving devotional and ritual observances, and often containing a moral code governing the conduct of human affairs.

Jam it back in, in the dark.

Look at that cat. Look at it. That cat is fat. That cat is short. Look at that short fat cat. My hat fits that cat. My hat is fat, and short. Put the short fat hat on the short fat cat. Look at that short fat cat in the short fat hat. Look at that! Here comes longcat! Longcat is loooooooooooooooooooooooooooong

I think we've gone a little off subject here. I'm gonna go ahead and disagree with the statement that "Faith is, in a nutshell, the largest hindrance we've had to peace and justice in this world." I pose that fear (not faith) and the symptoms of fear (anger, jealousy, greed) would be such a hindrance. Faith, as I've come to find, often results in an absence or at least a quieting of fear, and therefore cannot possibly be a hindrance to peace and justice.

There's nowhere I can't reach.

I agree totally, Sass. That's why I said I disagreed with that original statement.

To further illustrate my point, I'll use a personal experience. My trust was betrayed in one of the worst ways by someone I thought would never betray it. Because of that, I've lost faith not only in people, but also in God AND in myself. That last being the biggest one, and a catalyst for the lost faith in everything else. Without faith in myself, I'm more susceptible to fear, and that fear has made me do some things I'm very ashamed of - not even necessarily big things, but I'm lashing out at people more frequently, and not caring how they feel. I was so focused on myself, because I was afraid to put any part of my life or my choices in others' hands. And then there were negative consequences. It's easy to see how the absence of faith can destroy us.

But yes. Faith in anything other than ourselves can also be destructive. I would disagree that faith in God is destructive, because God is greater than ourselves, in my opinion, but for me it's not blind faith motivated from fear. I'm sure you can see the difference, and the connection there. Blind faith in anything can very probably become destructive.

How ya doing, buddy?