As you may know, Charles Darwin studied to become a clergyman before settling on biology. It is said that he finally lost his faith, long after publishing his controversial theories, when his daughter died as a child.
Like many of us, Darwin hoped his faith might spare him that kind of pain and suffering. If you read the bible though, you'll see fairly clearly that the faithful and the faithless often share the same fate.
The promise of faith is not that you'll have a better time of it here on earth. The promise of faith is that this isn't the end of the story. Though we can't see it or tell anything about it, faith promises us that we transcend these bodies and we survive the suffering here on this planet.
I can't imagine the pain Darwin endured on losing his child. There can't be anything worse. Nor can I blame him for losing his faith in the wake of such a tragedy, even though it was really the only thing I can think of that might offer some solace to a man in that horrible position.
Darwin's suffering did end though, with his death; and I believe, he and his beloved daughter were then reunited in a way unimaginable here on earth.
Though often vilified by the faithful, Darwin gave us much knowledge with which we can celebrate and marvel at the beauty of God's creation. His work brings me much closer to God because, through it, I can see the brushstrokes of the master's creation. I only wish his faith had brought more comfort in his own life.