How did the Protestant Reformation begin a process of rationalisation?
According to Max Weber, the Protestant Reformation (and most specifically the teachings of Calvin) led to a process of rationalization of society. This ended up, he said, putting people in "iron cages" in which nothing was important except for work and rationalization.
Weber pointed out that Calvinism sees hard work as a way of showing that a person may be among the elect. It is a way to show that you honor God. Therefore, working hard becomes much more important than it once was. Once working hard becomes almost a sacrament, it is important to find ways to work harder and more efficiently. This is where rationalization comes in. The more that we rationalize our society, the more efficiently we can work. The more efficiently we work, the more we glorify God. In this way, the Reformation began a process of rationalization of society that would not (arguably) have happened under the Catholic Church.