  We study the possible interpretation of the "universal constants" by the
classification of J.~M.~L\'evy-Leblond. $\hbar$ and $c$ are the most common
example of constants of this type. Using Fock's principle of the relativity
w.r.t. observation means, we show that both $c$ and $\hbar$ can be viewed as
manifestations of certain relativity. We also show that there is a possibility
to interpret the Boltzmann's constant in a similar way, and make some comments
about the relativistic interpretation of the constant spacetime curvature and
gravitational constant $G$.
