All social phenomena as sum of individual choices (and nothing else). People make rational, optimal choices. Idealism
The idea that all action is fundamentally 'rational' in character and that people calculate the likely costs and benefits of any action before deciding what to do is common in Economics. This approach to theory is known as rational choice theory, and its application to social interaction takes the form of exchange theory. In RCT, as a theory of religion, it means that people will seek the religious organization which best satisfies their needs.
Rational choice theory assumes human behavior is guided by instrumental reason. Accordingly, individuals always choose what they believe to be the best means to achieve their given ends. Thus, they are normally regarded as maximizing utility, the "currency" for everything they cherish (for example: money, a long life, moral standards).