In exceptional cases it was permitted to a soul to reappear for a while in the sensible world of the living or for a still living man to pay a short visit to the fields of the dead. These rather crude representations have been sublimated by religious doctrines and by idealistic philosophy. While the primitive descriptions of a realm of souls and the activities of its inhabitants cannot bear critical examination and can easily be exposed to ridicule, it is impossible both for aprioristic reasoning and for the natural sciences to refute cogently the refined tenets of religious creeds. History can explode many of the historical narrations of theological literature. But higher criticism does not affect the core of the faith.
Reason can neither prove nor disprove the essential religious doctrines.
But materialism as it had developed in eighteenth-century France was not merely a scientific doctrine. It was also a part of the vocabulary of the reformers who fought the abuses of the ancient regime. The prelates of the Church in royal France were with few exceptions members of the aristocracy. Most of them were more interested in court intrigues than in the performance of their ecclesiastical duties. Their well-deserved unpopularity made antireligious tendencies popular.