I'll tell you a secret, Darwin repented towards the end of his life. After his death, his wife didn't know what to do with all his scientific work, so she gave it all to his old collegues. It was from them that the theory of evolution sprouted. The journey/odessy Darwin went through about the meaning of it all, in my opinion, shouldn't be as testimony against him, but rather testimony for all to learn from, Darwin finally decided there was a God, after all his searching.

It was his own personal search, it was others who exploited his material. The difference between Darwin and most believers is the fact he was a scientist and documented everything while he was on his quest of discovery. Most christians however do not document and rarer yet, are scientists. Therefore, we don't always have those confessions or testimonies from those who werent saved, or recently saved rather, save that which is from word of mouth.

The reason it spread like wildfire is simply because it was something a "learned" individual could grasp as opposed to a creator. And multiplied by the fact that men are naturally rebellious to God, well, you can see the aftermath.

trust me, Heaven is going to have some really interesting people there, and it ought to be one heck of a party.