Many fields apply threshold and linear theories, for example, psychology, mathematics, archaeology and economics. Political science threshold theory and linearity theory (or linear theory) borrows from these and adapts them to the concerns of political science. This is because specialists in various fields collect together in the discipline of political science to answer questions about dynamic interworkings between political forces and powers and civil society, such questions as: "What is the human condition? What is the meaning of civil society?" (University of Nevada, Reno).
Linear theory holds that for social or political development to occur, given events or advancements must take place in a linear fashion: one event precedes the next, which itself precedes the next. For example, for democratization to occur in underdeveloped countries, linear theory asserts that national gross domestic product (GDP) and per capita GDP must first reach a sufficiently high level to counter tendencies toward authoritarianism, then democracy will develop.
Threshold theory holds that for social or political development to occur, a certain threshold of advancement must first take place among the "human capital," or population, and that sociopolitical conflict must not pass the social tolerance threshold. For example, instead of technology leading to more trade leading to lifestyle advance among the population in linear fashion, the population must experience well-being before technology and trade can lead away from authoritization and toward democratization.