Because the study of society is very extensive and complex people have different views and opinions about it. These views are called perspectives. Perspectives can be a source of conflict because not everyone will agree with some of them, especially when a group of individuals within society are criticized. When this is the case the perspective is called conflict theory or conflict perspective. Marxism and feminism are two conflict perspectives. Other sociological perspectives are functionalism , interactionism, post-modernism, collectivism and New Right.
I will explain all this perspectives though the next posts.
An introduction to Sociological Perspectives 