This article departs from a mereological conceptualization of the Daoist metaphysi- cal system in the Daodejing 道德經. I discuss what parthood status applies to dao 道. Whereas it is quite intuitive that you 有—the region of concrete objects—has parthood relationships and compositions (entities made from parts), the other, undif- ferentiated region, dao, poses a considerable problem. This problem can be charac- terized in the following way: (a) dao cannot be characterized as a particular com- position, which entails that it does (...) not include parts. However, (b) dao underpins compositions in you, which entails that it contains compositions or at least parts that make compositions in you. This generates a problem of how compositions are possi- ble with an undifferentiated ontological foundation. I focus on one possible approach to this problem––mereological nihilism, according to which no composition is pos- sible. Assuming nihilism entails dao composed of mereological simples––funda- mental entities, which are not parts. (shrink)