But the kind of religion that will prosper depends to a large degree on the impact of cultural secularization. Cultural secularization goes hand in hand with what sociologists describe as modernization. This becomes clearer by contrasting traditional cultures and those that are characteristically modern. In traditional societies the religion, occupation and customs of individuals are determined not by personal choice but by the family and neighborhood in which they were born and raised. Modern society, by contrast, is highly mobile.
People change their residence and occupation very freely.
This individual choice often carries over into the sphere of religion. The Church becomes for all practical purposes a voluntary association. Religion is considered a private matter in which people can make their own choices. Many opt out of the church and the religion in which they were raised. Sometimes they come back to it, sometimes they join another religious body.