In one scene a college professor was lecturing to his class about the demise of Christianity in America. Here is part of his lecture that I found particularly compelling:
"All right. Let's get to the final cause of Christianity's demise in America. I label this one lack of distinctiveness. It may be a little hard for us to get our brains around this, because we don't think in these terms anymore; we don't expect people to be different based on a set of religious views, but stick with me.
From its outset the Christian religion claimed that the intervention of the deity in people's lives would change people for the better. They would have a different character. They would have different morals. They would think, speak, and behave differently. They called it Christlikeness-- 'Christ,' of course, being the title given to Jesus of Nazareth.
This alleged change in people wasn't caused just by the religious adherent's efforts to be good, although that was certainly emphasized as well. Rather, it was also brought about by the presence of something Christians called the Holy Spirit. This Holy Spirit was supposed to change a person's character so that others could see them living like Jesus.
This belief worked as long as the vast majority of people in society were professing Christians, because there was no one to compare Christians to. The crack in the foundation appeared when people began abandoning Christianity. When a large segment of society became openly nonreligious, an amazing thing happened--amazing to the religionists, anyway. People discovered that religionists and nonreligionists behaved similarly. Sexual behavior, divorce rates, self-reported levels of honesty--none of these varied significantly between religionists and nonreligionists.
In short, the supposed influence of the deity to change people wasn't real; it was all a psychological game. As people realized that, more of them concluded, 'Why should I adopt that belief system? It doesn't cause a real change in anyone.'
So this produced a cascade effect in which the younger generation--people born in the 1980s and after--looked at the older generation and didn't see a difference in their lives. As a result, they didn't follow in the footsteps of their parents' religion. What the religionists didn't know was that, as early as the first decade of this century, only a third of those growing up in Christian homes were, upon reaching adulthood, retaining the faith. And converts to the faith were declining as well.
The result for American Christianity was cataclysmic. The number of adherents to Christianity spiraled downward as most of each succeeding generation rejected it... Throughout the twenty-first century, Christians were trying to pass along their religion to generations who simply didn't buy it."