Christians have made numerous of claims that have turned out to be wrong. Everyone knows about a few of them: the age of the earth, where biblical stories came from, how the diversity of life on earth arose, the impossibility of an Australasian continent, the biblical chronology, the nature of disease, and the structure of the solar system are a few examples.
Up until the late Middle Ages, Christians believed that science was entirely consistent with Christianity. According to the orthodox line God had written two books: the Bible and the natural world. Truth cannot contradict truth, so it followed that the two books must necessarily be fully in accord. If they appeared not to be, then that was because of our limited understanding.
By the end of the Enlightenment this position had become untenable for educated Christians. It was clear that the bible did contradict the evidence of the natural world. By the time Darwin published his Origin of Species the case was already closed, although the shouting continued. It continues today, although the number of biblical literalists in the West is now minute outside the most backward parts of the USA.
The only realistic reaction to the growing realization that nature and the Bible contradicted each other was religious retreat. Very slowly Churchmen started acknowledging, often in a round-about way, that Christianity did not provide some of the answers. The bible had traditionally been a comprehensive encyclopedia of all world knowledge. Now it was something less than that.
One solution to the problem, as religious minds saw it, was the idea of “non-overlapping magisterial”. In this solution the Church accepted that it had overstepped itself in the past and had erred. It had trespassed into areas where it had no dominion. There were two separate areas of teaching: science addressed questions of how things are as they are, and Christianity addressed questions of why things are as they are. According to this idea, science and religion occupy two fundamentally different and distinct domains of inquiry, two inherently different kinds of knowledge, two non-overlapping magisteria.
This idea has found a number of supporters, including some in the scientific community. In principle it appeals to accommodating types who would like to see science and religion get along together. Stephen J Gould for example was an advocate, though he seems never to have fully thought it through.
The weakness is that the idea only works if the Church makes a full retreat. There are Church leaders who have tried to make such a retreat. Liberal theologians are safely ensconced in a world where Christianity makes no claims about real historical events, or about anything testable. For them the virgin birth and the resurrection are true only in some vague mysterious non-factual sense. God’s revelation is inherently ineffable. Their position is not unassailable, but for present purposes we will leave them in the safety of their mystical island far removed from the worlds of science and reality.
For Christians other than the most ethereal divines, the solution of non-overlapping magisterial does not work. Traditional Christian doctrine cannot help leaking out of its own magisterium and into the scientific magisterium.
First, it is necessary to redefine a whole host of traditional ideas. Heaven, Purgatory, and Hell can no longer be real places in the physical universe, at a known distance from the surface of the earth, which can be visited, heard or seen by living people in the flesh as they used to be. (In the 1960’s space exploration was opposed by Christians on the grounds that astronauts were trespassing in heaven. One Russian Cosmonaut countered that he’d had a look and God wasn't there. On the internet you can easily find Christian websites claiming to have recordings of the screams of souls in hell, but this is now considered eccentric even by other Christians).
Similarly, Christians had to give up the traditional idea that the soul was a physical organ in the body. (It had been thought to be, or to be part of, the pineal gland). Research to find it stopped, as did experiments to establish its mass by weighing human bodies just before and just after death. The bonus here was that if we cannot find the soul, then we have no chance of seeing the various stamps that God puts on it to mark the sacraments it has undergone.
On the other hand all sorts of supernatural phenomena are able to remain on the grounds that they are not physical. So we can keep angels, demons, ghosts, sanctification, transubstantiation, life-after-death, and religious experiences – as long as we define them in such a way that they are inherently untestable. As has been observed before, this involves a degree of intellectual dishonesty. No philosopher, other than tame theologians, would accept that the Catholic doctrine of transubstantiation is even meaningful, let alone true.
This opens up another problem for the non-overlapping magisterial theory. In which of the magisteria does philosophy sit? In medieval times philosophy was a branch of theology, but it bore no fruit, withered away, and is now studied only by historians. Modern philosophy is overwhelmingly secular, and has comprehensively discredited every attempt to reinvent theological philosophy. None of the traditional “proofs” of the existence of God survived the Enlightenment. If the Churches had accepted the loss of all philosophical territory then the two magisteria would not overlap. But the Churches have not retreated. There are still University departments of philosophy run by theologians. The Catholic Church is still formally attached to the long-discredited Medieval philosophy of Saint Thomas Aquinas. And Christians regularly cite medieval "proofs" of God's existence that no reputable philosopher has espoused for centuries. The two magisteria do overlap because Christians have refused to move away from the territory they lost long ago.
There is another problem here. Most Christians are not willing to retreat into the territory of their own magisterium. For example those angels and demons are alright as long as they don’t do anything. But what if they do. What if demons start possessing people, and taking over their behaviour, and need exorcising. Now you might think that the mainstream Churches had abandoned such ideas long ago. But they have not. All mainstream Churches still employ exorcists to deal with naughty demons who possess believers (oddly, these demons only ever possess believers). The phenomenon of demons possessing people is by its nature one that can be investigated scientifically. Whoops. The two magisterial just overlapped again.
And there are other overlaps. The efficacy of petitionary prayer can be tested. It has been tested and shown to be totally ineffective – but the fact that it can be tested places it in the science magisterium. There are any number of examples like this. Christians who claim to be able to determine the moment of a person’s death (an ability denied to all general practitioners of medicine). Holy relics that work miracles. Christians who can “feel” the sanctity of a sanctified place, and so on.
Yet another problem is that of religious experience. Neuro-scientists have found that by electronically stimulating a certain part of the brain they can generate experiences that the subject regards as “religious”. As you might expect, people of difference religious traditions enjoy different experiences, so that Christians enjoy typically Christian experiences. In which magisterium does this belong? A scientific experiment about religious experience is not easy to place fully in either magisterium.
The whole idea of non-overlapping magisterial is weak as long as Christians continue to make any substantial claims at all.
Now, let’s go back to those liberal theologians who thought they were safe on their remote island of fuzzy thinking and no substantial claims about anything. The central concept in Christianity is the doctrine of Original Sin. No matter that it was invented well after the time of Jesus. No matter that it lacks rational coherence. It is central to Christianity. The doctrine goes like this: Adam and Eve sinned by eating of the Tree of Knowledge. Their sin was so great that (for some reason that has never been articulated) God needed to sacrifice himself in order to expiate such a great sin. Here’s the problem: this central idea depends on a real event, where real people committed a real sin. But our liberal theologians on their island accept that Adam and Eve did not really exist. If they did not exist then they did not sin. And if they did not sin, then there was no sin to expiate, and no need for the crucifixion of resurrection. In other words the whole foundation of Christianity is removed.
The upshot is that those liberal theologians have not found a safe refuge after all. The two magisteria do overlap, and always will as long as Christianity holds to its most central doctrine.