*advocates applying the results of population studies over
  mechanistic reasoning * in diagnosis, prognosis and therapy."

  in short, it has to do with population generalization and the
  overuse of it. It *is* overused. Things with nice neat lines
  like physics are easy to use statistics with. Messy things like
  biology don't conform as well to statistics, medicine even less
  so. Case studies are appropriate generalizations - and they're
  not even generalizations; they're case studies - archetypes
  that, when considered in an overlapping fashion, can lead to
  some similarities to a current case.

  They work.

  Statistics are alluring and tempting but they're not appropriate
  as the MAIN basis for diagnosis, only as a supporting role.