The theory of structural functionalism believes that society is a structure of interrelated parts. These parts are designed to meet the social and biological needs of an individual within a particular society. Structural functionalism developed from the writings of Herbert Spencer who observed similarities between the human body and society. Spencer argued that just like every part of the body works with others to keep the body functioning, the various parts of society also work to ensure that society is functioning. Spencer referred to these parts of society as social institutions that work to meet the social needs of every aspect of society including religion economy, family, education, and government. Durkheim applied this theory to explain changes in society over time. He stated that society is a complex system made of interdependent and interrelated elements that work together to achieve and maintain stability. He stated that society is inherently bonded by shared values, symbols, and languages. Therefore, to holistically study a society, it is important to look beyond an individual and consider social aspects such as morals, laws, values customs, etc., which govern social life.
Unlike Durkheim who believed that various parts of society work together to achieve stability, Karl Mark believed that society is always in a perpetual state of conflict as the various parts compete for limited resources. Karl Marx asserted that social order is only achieved and maintained by power and domination and not consensus and conformity. Those who have power and health often try to hold on to it with all their might, thus oppressing the powerless and the poor. The main premise of this theory was that groups and individuals in a society will always work to maximize their power and wealth. However, like Durkheim, Marx acknowledges that there are various parts of society.