Value theory, also called axiology, studies the nature, sources, and types of values. It is a branch of philosophy and an interdisciplinary field closely associated with social sciences such as economics, sociology, anthropology, and psychology.
Value is the worth of something, usually understood as covering both positive and negative degrees corresponding to the terms good and bad. Values influence many human endeavors related to emotion, decision-making, and action. Value theorists distinguish various types of values, like the contrast between intrinsic and instrumental value. An entity has intrinsic value if it is good in itself, independent of external factors. An entity has instrumental value if it is useful as a means leading to other good things. Other classifications focus on the type of benefit, including economic, moral, political, aesthetic, and religious values. Further categorizations distinguish absolute values from values that are relative to something else.