
 TIME 100: Ludwig Wittgenstein 
  As a young engineering student in England, Wittgenstein saw the hope of the new mathematical logic, and rushed to Cambridge to become the protege of Bertrand Russell, whose monumental "Principia Mathematica" (1913), written with Alfred North Whitehead, was an attempt to reduce all mathematics to logic. 
  Wittgenstein's first book, published in England in 1922, the even more grandly titled "Tractatus Logicophilosophicus," went even further, and was thought by him, and by some of his admirers, to have brought philosophy to an end, its key problems definitively solved once and for all. 
  The "later Wittgenstein" spent the next 18 years agonizing in front of a small Cambridge seminar of devoted and transfixed students, who posed curious questions that he then answered — or pointedly did not answer — with wonderfully austere if often enigmatic aphorisms. 
 www.time.com /time/time100/scientist/profile/wittgenstein.html (385 words) 
