 A reasonable paraphrase of the standard formulation would be “Water is a collection of H2O molecules.” However, although the expression “H2O molecule” describes a particular microentity, it by no means exhausts the kinds of microparticles in water, and says nothing of the microstructure by which they are related in water. Describing the microstructure of water completely involves elaborating the details of this interconnected structure, as well as detailing how they depend on temperature and pressure, and how they change over time (Finney 2004).