The term “Quantified Self” refers to a movement that two american journalists (Gary Wolf and Kevin Kelly) started in 2007. Members of the movement are tracking a high number of bodily functions with the goal of „self knowledge through numbers“ (https://quantifiedself.com/). They are meeting at regular meetups and share the produced data online with other members of the community. In the context of the Quantified Self movement emphasis is put on empirical data, which can lead to the disbelieve in the necessity of theories. “Quantified self” is closely related to the concept of “Datafication”.