The theory of value has three main traditions: subjectivism, which holds that the only valuable goods are subjective states of sentient beings; objectivism, which claims that while values must be human-related, they exist independently of us; and Neo-Kantian rationalism, which suggests that value is postulated on the basis of practical reason. Central distinctions in the theory of value are between subjective and objective values, instrumental and final values, intrinsic and extrinsic values, organic unities and the idea of an ultimate or architectonic value. There are also distinctions drawn between different types of value, such as moral and aesthetic value.
Accuracy of subjective measurements made with or without previous scores: an important source of error in serial measurement of subjective states.