TLDR: Short answer, Christianity was in decline prior to WWII. Some point to the industrial revolution as to when this change began happening, and by the 1880s, one can see a transformation in religion, as scholarship becomes more critical, and theology has secularism interjected into it. In the US, you also have the rise of the Fundamentalist movement, which is push back to the secularization, which moves from the idea of being religious to spiritual, which effects polls. This all leads up to the Second World War, where people are faced with the problem of evil, and the classical view of God, the all powerful and all loving God really dies off, while theologians try to explain the issue of suffering. This leads to more of a drop off in Christianity as the impact of the Holocaust really changed almost everything. This decline though is felt more in Europe, as by the 1980s, Christianity again begins to rise in the US.
This is a rather complicated question. WWII, and specifically the Holocaust, changed religion dramatically. According to Murray Haar, in his article, God, the Bible, and Evil after the Holocaust, states that two questions really arise. “Where was God, and where were we?” The whole idea of how God and evil relates was changed after the Holocaust. For many, this meant that the classical view of God, as all loving and all powerful, was dead.
In God’s Problem, Bart Ehrman lays out the basic view of theodicy, which deals with the idea of how can God be just if there is so much suffering. This leads to the problem that is based on three assertions. God is all powerful. God is all loving. There is suffering. Not all of these can be true, and that means that to view God, one has to shift the first two assertions a bit. For others, that meant leaving the faith.
There have been theological arguments that attempt to explain those three assertions. My favorite is by Rabbi Harold Kushner, in his book When Bad Things Happen to Good People. He argues that God wishes to intervene, but God’s hands are tied. This has been adopted by others to form a panentheistic view of God, which states that God is both part of us, but also greater than us. So we all have a spark of creativity but to allow that spark to really shine, God has to take a more hands off approach to allow humans to be the creative humans they were created to be. But in order for creative processes to be had, you have to have chaos as well, which can lead to evil. This is the view that Alfred North Whitehead, and process theology have moved towards.
That is the religious environment that sprouts up after WWII. Seeing the immense evil of the Holocaust demanded that the question of evil and suffering really be addressed. This was especially true for Jewish people. For instance, Elie Wiesel, a Holocaust survivor and author of Night, speaks of how God was put on trial at Auschwitz. The ruling was that “God owes us something,” or chayav.
There was also something else that had begun in the late 1800s and was kind of wrapping up in the first decade or so of the 1900s. Albert Schweitzer, in his The Quest for the Historical Jesus, outlines how the view of Christianity was changing. His book was published in 1906, and what his attempt was was to look at the scholarship up to that point on Historical Jesus research. But it also gives us an overview of the trends in Christianity at those times.
Going up through the 1800s and to the 1900s, a less literal approach was being given to the Bible. It was a rise of critical reading of the texts. A lot of the miraculous or supernatural was being disregarded outright, or attempts to explain them through natural means was what was happening. This was spreading not only in the scholarship but also to the lay audiences. So by the time of the 1880s, you begin to see a decline in religious affiliation and you get a push towards more spiritualism. Those who believed in God wasn’t declining too fast, but those who identified by a religion was declining. In this you also get the rise of the Fundamentalist church, which was a push back against this more liberal view, as well as the idea of Spiritualism, which was more centered on connecting with spirits and the like.
Martin E Marty has done some great work on this time period and specifically on Fundamentalism. He was part of the Fundamentalism Project, but well worth a read here is Pilgrims in Their Own Land: 500 Years of Religion in America. He speaks of how we see a transition from people belonging to a certain denomination, and from attaching a religion to them, to saying they are more spiritual. With that, we get a rise of non-denominational churches as well as inter-denominational churches. And all of this is leading up to the second World War, especially in the United States. Europe had some of the same makings, but Fundamentalism didn’t take a hold there.
For the United States, after the War, while there was still a decline, it wasn’t the same as in Europe, and this may have been because there was a different religious foundation in the States. While places like France and England had state religions, the US did away of that and forbade the country from adopting such a practice. This, according to Dr. Mark Hall of the Heritage Foundation, probably made religion more popular in the states. Unlike in Europe, where the churches were supported by tax dollars, in the US there was more of a free market, so religious organizations had to be more innovative.
That is probably why Christianity rebounded more so in the United States later on. Walter H Capps, in The Quest for Transcendence, looks at how in the 60s, it was declared that God is Dead. America was becoming much more secularized leading up to the 60s and into the 70s, but by the end of the 80s, religion was once again rising. Part of this is because of the fundamentalist movement and a new sort of revivalism.
In Europe, the decline had also began earlier than the second World War. According to Thomas William Heyck, in his article, The Decline of Christianity in Twentieth-Century Britain, for Britain, the decline began with the industrial revolution. It brought in an era of modernization, which helped spawn more of a secular culture. Modernization didn’t produce hostility to Christianity, but it did help people feel more secure and less powerless. We also have the rise of modern science which didn’t directly compete with Christianity, but what we see is theologians trying to integrate science and religion, which made the theology more secular. This is really what Albert Schweitzer was also addressing.
But in Britain, up until the First World War, all the Christian denominations continued to grow, but by the 1880s a shift begins appearing. During the First World War, number fell, and while they would steady themselves in the 20s, and even recover in the late 1940s and 50s, by the 1960s, they were declining as well.
So in Britain, we do see a modest rise after World War II, but it didn’t last. The decline that had already begun in Britain was simply propped up by a few years of what could be considered the shock from the horrors of the Second World War. And then we have the question again rising, if God is all powerful and all loving, how did the Holocaust happen.
Now, I can’t cover all of Europe, but I will touch on Germany quickly. Jack D Shand wrote a great article titled The Decline of Traditional Christian Beliefs in Germany. He’s looking at just the time from 1967 to 1992 in his article. But Germany had a lot of the same similar ups and downs with religion as Britain did.
I mention Germany because I think they can really show why there was a decline. So in West Germany, from 1967 to 1992, the belief in God fell from 68 percent to 56 percent. People were also going to church a whole lot less, and traditional beliefs fell. For instance, in 1967, 42 percent believed Jesus was son of God. In 1992, that number had dropped to 29 percent.
Much of this was split along a generation gap as well. Those who were 30 or younger only half as many believed that Jesus was the son of God, as compared to those who were older. There was also a push back against the Pope, with 54 percent of those who attended Mass in 1967 accepting the infallibility of the Pope and the Virgin birth, to only 36% believing the same in 1992.
Most telling though was that non-traditional forms of Christianity, those who say they are spiritual and not religious, grew considerable during that time. While traditional Christianity was shrinking (such as Catholicism and the major Protestant churches), non-denominational or what could be called heretical forms of Christianity were growing.
This is the trend that we see in not only Germany, but also in the United States and Britain (more so in the US). After WWII, while there was a decline, there also arose a larger movement that didn’t consider themselves religious, but spiritual. In Germany and Britain, this didn’t amount to a growth in theist views over all, but in the US, by the 80s, there was a revival taking place.
