  In the paper by P. Quincey (2020) [1], the author claims that angles are not
dimensionless quantities and that the radian should be a new independent base
unit. However, the claim is not supported and the proposed redefinition will
cause several problems not only in physics, but also in mathematics. The
proposed "unhiding" of the radian will bring hidden problems not discussed in
detail. This includes e.g. an introduction of quantities of different kind for
time and the corresponding units defined as the second per radian.
