  Based on the results of F. Wilf on the need to take into account the
quantum-mechanical correspondence rules in the Dirac equation for an electron,
it was shown that the equation obtained by giving physical meaning to
$\alpha$-Dirac operators should be considered as a phenomenological equation
for a particle of non-zero size - the EM polaron, previously introduced by the
author. This allows a solution to be found to the inherent paradox of the Dirac
equation, which consists of the equality of the velocity of the moving
particles to the speed of light $c$ in a vacuum, which is a priori
unobtainable, and to understand the physical essence of spin as the intrinsic
mechanical moment of an EM polaron. It is also shown that the Dirac-Wilf
equation for a single spatial dimension can be considered a generalization of
the Schrodinger equation for relativistic energies.
