Predicting future duration from present age: Revisiting a critical   assessment of Gott's rule
  Gott has promulgated a rule for making probabilistic predictions of the future duration of a phenomenon based on the phenomenon's present age [Nature, Vol. 363, 315 (1993)]. I show that the two usual methods for deriving Gott's rule are flawed. Nothing licenses indiscriminate use of Gott's rule as a predictor of future duration. It should only be used when the phenomenon in question has no identifiable time scales. 
Carlton M. Caves (University of New Mexico and University of   Queensland)