People seem to need an overarching explanation of things—of origins, meaning, purpose, and destiny. Christianity provided these things for a long time but, at the close of the Enlightenment, was losing its luster among the educated. Too much in Christianity just didn’t make sense in light of continuing discoveries. The sciences were more compelling, and a better fit for the changing mood of the times.

Do you ever feel like you are addicted to email or twitter or texting? Do you find it impossible to ignore your email if you see that there are messages in your inbox? Have you ever gone to Google to look up some information and 30 minutes later you realize that you’ve been reading and linking, and searching around for a long time, and you are now searching for something totally different than before? These are all examples of your dopamine system at work.