The correlation in temporal evolution of water molecule positions is independent of any observer, but is drastically different in "liquid" and "gas" and "solid". Thus, the different phases of matter have an ontological reality independent of observer. They are a consequence of the microscopic properties and configuration, but the emergence manifests physically, not in our heads.

We can use our heads to observe the regularity--whether it's gravity, elastic collisions between neutrons, viscous drag in liquids, or "being alive"--but the regularity isn't a property of our heads.