Academic course work in all disciplines is an abstraction from reality.
Similarly, historians explain events of the past as the consequence of middle class aspirations, economic structures, disease, or even divine intervention, but they do not point to all these possibilities since to explain something by saying it is caused by everything ultimately explains nothing. Since it is impossible or meaningless to teach all things, selections are made. In describing the development of American political theory, for example, most political science courses emphasize significance of, among others, Aristotle, John Locke, and Thomas Hobbes. Ideas, however, do not exist, as they often must be taught, in a vacuum. The degree of importance attached to ideas about political institutions is determined by the social, cultural, economic, and historical context of the people who consider those ideas.