Predicting Future Duration from Present Age: A Critical Assessment
  Using a temporal version of the Copernican principle, Gott has proposed a statistical predictor of future longevity based on present age [J. R. Gott III, Nature 363, 315 (1993)] and applied the predictor to a variety of examples, including the longevity of the human species. Though Gott's proposal contains a grain of truth, it does not have the universal predictive power that he attributes to it. 
Carlton M. Caves (University of New Mexico)