Taking into account four universal constants, namely the Planck's constant
h, the velocity of light c, the constant of gravitation G and the
Boltzmann's constant k leads to structuring theoretical physics in terms of
three theories each taking into account a pair of constants: the quantum theory
of fields (h and c), the general theory of relativity (c and G) and
quantum statistics (h and k). These three theories are not yet unified but,
together, they underlie the standard models that allow a satisfactory
phenomenological description of all experimental or observational data, in
particle physics and in cosmology and they provide, through the modern
interpretation of quantum physics, fundamental metrology with a reliable
theoretical basis