Religion has declined in modern society because it has been overtaken in importance by institutions such as science and technology. Bruce argues with the theory of technological worldview that science and technology have encouraged people to take religion less seriously as they perform the functions religion once did. Religion has lost its hold over society and is no longer needed. For example, when looking at the causes of a plane crash, people look for natural and not supernatural causes. The NHS has overtaken the importance of monasteries and home remedy practices. This is significant as it explains why areas that are less technologically developed are more religious and why religion has declined in the West specifically. However, this can be criticised because many decisions are still taken on faith and there has arguably been a growth of people going to things such as NAM's like clairevoyancy. Science has not replaced religion as it is often working alongside it. It is also problematic to make this generalisation about "contemporary" society because science and technology grew during the Enlightenment but religion only lost its influence in the public sphere recently. This is related to Weber's theories of rationalisation and disenchantment.
Furthermore, religion has declined in contemporary society because it has been replaced in its functions. Parsons argues in structural differentiation that society became more specialised during the industrial revolution and other specialist institutions replaced religion. For example, education was performed by schools and not religious institutions like the church. Religion loses its hold over society and religious institutions have to conform to the secular state like qualifications needed for faith teachers. This is significant because it shows how religion has declined visibly in the public sphere. However, arguably religion has just changed and become confined to the private sphere, not declined. Religion still performs functions like education as people go to faith schools. There was an article exploring Muslim parents sending their children to Catholic schools. There are issues with defining how religion has "declined" because it is difficult to see secularisation in relation to beliefs, only institutions. This is related to ideas of primary socialisation and functionalist theories of the education system.