  Binney (2003) has argued that two-temperature radiatively inefficient
accretion flow models are unphysical because the electron-ion equipartition
time is much shorter than the accretion time. I show that this conclusion is
incorrect because it relies on a misidentification of the electron-ion
equipartition time. I also clarify what requirements must, in fact, be
satisfied to maintain a two-temperature accretion flow.
