Law of Nature.
The presented Law of Nature is a transformed ergodic Poincaré Recurrence Theorem, which originally told that certain dynamical systems will, after a sufficiently long but finite time, return to a state arbitrarily close to, or exactly the same as their initial state. Therefore, the Law of Nature, in the presence of molar characteristics and absence of any distance in particular, and geometry in general, goes like this:
— In a given molar volume there is always only this number of photons.
The Law is proved by the existence of the periodic table of chemical elements, where each atom always has a fixed number of its elements.