  Recently Flanagan [astro-ph/0308111] has argued that the Palatini form of 1/R
gravity is ruled out by experiments such as electron-electron scattering. His
argument involves adding minimally coupled fermions in the Jordan frame and
transforming to the Einstein frame. This produces additional terms that are
ruled out experimentally.
  Here I argue that this conclusion is false. It is well known that conformally
related theories are mathematically equivalent but not physically equivalent.
As discussed by Magnano and Sokolowski [2] one must decide, in the vacuum
theory, which frame is the physical frame and add the minimally coupled
Lagrangian in this frame. If this procedure is followed the resulting theory is
not ruled out experimentally. The discussions in this paper also show that the
equivalence between the generalized gravitational theories and scalar tensor
theories discussed by Flanagan [gr-qc/0309015] is only mathematical, not
physical.
