Protestantism has had an important influence on science. According to the Merton Thesis, there was a positive correlation between the rise of English Puritanism and German Pietism on the one hand and early experimental science on the other. The Merton Thesis has two separate parts: Firstly, it presents a theory that science changes due to an accumulation of observations and improvement in experimental technique and methodology; secondly, it puts forward the argument that the popularity of science in 17th-century England and the religious demography of the Royal Society (English scientists of that time were predominantly Puritans or other Protestants) can be explained by a correlation between Protestantism and the scientific values. Merton focused on English Puritanism and German Pietism as having been responsible for the development of the scientific revolution of the 17th and 18th centuries. He explained that the connection between religious affiliation and interest in science was the result of a significant synergy between the ascetic Protestant values and those of modern science. Protestant values encouraged scientific research by allowing science to identify God's influence on the world—his creation—and thus providing a religious justification for scientific research.