  On his way to General Relativity (GR) Einstein gave several arguments as to
why a special relativistic theory of gravity based on a massless scalar field
could be ruled out merely on grounds of theoretical considerations. We
re-investigate his two main arguments, which relate to energy conservation and
some form of the principle of the universality of free fall. We find that such
a theory-based a priori abandonment not to be justified. Rather, the theory
seems formally perfectly viable, though in clear contradiction with (later)
experiments. This may be of interest to those who teach GR and/or have an
active interest in its history.
