To understand the fundamental principles of life it is necessary to study living systems bottom-up. Building a synthetic cell will be a key step in this direction and will undoubtedly have a great impact on science and society as well. A quote from the theoretical physicist Richard Feynman “What I cannot create, I do not understand” sums it all up. From my perspective as a theoretical physicist a truly quantitative approach towards understanding living systems will require that we are able to build such systems and at the same time develop novel theoretical concepts and paradigms. The flagship would enable us to reach this goal and fundamentally change the way we view living systems.