In his work The Crisis of European Sciences and Transcendental Phenomenology, Husserl pointed out that the crisis in European science can be traced back to the mathematization of the lifeworld. The critical situation that led European civilization to world wars arose because the foundation of the lifeworld—based on practical wisdom that precedes scientific research—was in danger of being lost due to a worldview based on mathematical natural science. The foundation of the lifeworld here is nothing other than intersubjectivity, which is based on passive synthesis. When the objectivity of all disciplines, including mathematics, which is based on the intersubjectivity of the lifeworld, is forgotten, theoretical intellect becomes detached from the lifeworld and runs the risk of losing both its origin and its purpose. Overcoming this crisis is possible by clarifying the origin and purpose of science. This also means resolving the paradox of human subjectivity—that it constitutes the entire world and at the same time is only a part of its objectified world. For Husserl, this paradox is resolved through intersubjectivity in the lifeworld, as will be shown at the end of this chapter.