The German sociologist Max Weber recommended an interpretation of social action that differentiated between four different idealized types of rationality. The first, which he called Zweckrational or purposive/instrumental rationality, is connected to the beliefs about the behavior of other human beings or objects in the environment.
The second type, Weber called Wertrational or value/belief-oriented. Here the action is taken on for what one might call reasons built-in to the actor: some ethical, aesthetic, religious or other motive, independent of whether it will lead to success.
The third type was affectual, decided by an actor's specific affect, feeling, or emotion – to which Weber himself said that this was a kind of prudence that was on the borderline of what he believed "meaningfully oriented."
The fourth was customary or conservative, determined by ingrained habituation. Weber stressed that it was very odd to find only one of these orientations: combinations were the standard. His practice also makes clear that he considered the first two as more important than the others, and it is debatable that the third and fourth are subtypes of the first two.
Psychology of Reasoning
In the psychology of reasoning, psychologists and cognitive scientists have guarded different positions on human rationality.
Richard Brandt suggested a 'reforming definition' of rationality, arguing someone is rational if their ideas survive a form of cognitive-psychotherapy.
The German cultural historian Silvio Vietta has revealed that rationality as a quantitative mode of scientific thought was an invention of Greek philosophy, generally of the Pythagorean School.