Predicting future duration from present age: a critical assessment

Using a temporal version of the Copernican principle, Gott has proposed a s tatistical predictor of future longevity, based on present age (Gott III, J . R,, 1993, Nature, 363, 315) and applied the predictor to a variety of exa mples, including the longevity of the human spec ies. Although Gott's propo sal contains a grain of truth, it does not have the universal predictive po wer that he attributes to it.