Even though, for example, physics and sociology are distinct disciplines, the thesis of the unity of science says that in principle they must be part of a unified intellectual endeavor: science. The unity of science thesis is often associated with a framework of levels of organization in nature, where physics is the most basic, chemistry the level above physics, biology above chemistry, sociology above biology, and so forth. Further, cells, organisms, and cultures are all biological, but they represent three different levels of biological organization.