Value theory encompasses a range of approaches to understanding how, why, and to what degree persons value things; whether the object of valuing is a person, idea, object, or anything else. This investigation began in ancient
philosophy, where it is called axiology or
ethics. Early philosophical investigations sought to understand
good and evil and the concept of "the good". Today, much of value theory aspires to the
scientifically empirical, recording what people do value and attempting to understand why they value it in the context of
psychology,
sociology, and
economics.