In sociology, rationalization refers to the subjective reasoning that leads an individual to perform a certain act. According to Max Weber, there are at least four different kinds of rationalization. The two primary forms are instrumental rationalization and value rationalization.
Instrumental rationalization is the form of reasoning that emphasizes an end point or goal. When people engage in instrumental rationalization, they acknowledge that the action they are performing is merely a means to achieving the desired end. Value rationalization emphasizes intrinsic factors, such as ideology, ethics, or perceived intrinsic value.
Consider the example of a person who walks to work every day. If he states that the reason he walks to work every day is because walking is most convenient or because he cannot afford any other form of transportation, then he is engaging in instrumental rationalization. If he states that he walks to work every day so as not to contribute to carbon emissions or because daily walking is a part of his spiritual practice, he is employing value rationalization.