  We compare a recent excitation chain argument for the glass transition with
the earlier random first order transition theory. The key equation determining
the activation barriers and size of cooperatively rearranging regions has the
same scaling form in both approaches. The random first order transition theory
unambiguously predicts the coefficients in the equation giving results that
agree with experiment vis a vis the correlation of activation barriers with
thermodynamics and that also agree with experimental determination of
correlation lengths following the prescription of Berthier et al. The
excitation chain approach, while containing more adjustable parameters
accommodates those experimental findings only by using unphysical values for
those adjustable parameters.
