For those who do not make the transition to a matured, more spiritual self-will reason will indeed be no more than rationalization. Here is a prodigious parallel: just as in antiquity the dysdaimonic personality could not appreciate how his mentality was bound in by his characterological (banausic, doulic) biases, so in modernity the facile or abstractivist rationalist cannot comprehend how his "rationality" merely slavishly subserves his appetites, delusions, preconceptions, ideologies, etc.
