C. Wright Mills, in his classic introduction to sociology, The Sociological Imagination, makes this fascinating aside: The social science movement was born in the mid-19th century to “turn the troubles of lower-class people into issues for middle-class publics” (84).
Social science was invented by middle class reformers as a tool to convince other middle class people of the need for reform. The problems they wanted to reform were not primarily middle class problems, and definitely not upper class problems. The middle class wanted to reform the lower class. The instruments of social science were devised to give a name and a number to these problems, and to give reformers tools to fix them.
Each of the social sciences had developed more general theories, general tools, and some capacity to examine other classes and facts that are just facts without being problems.
The bread and butter of the social sciences, especially sociology, though, remains finding middle-class solutions to poor-peoples' problems.