I used to stand on the footbridge at Kennington, near Oxford, watching the trains go by, and determining that tomorrow I would place myself under one of them. But when the morrow came I always found myself hoping that perhaps Principia Mathematica would be finished some day. Moreover the difficulties appeared to me in the nature of a challenge, which it would be pusillanimous not to meet and overcome. So I persisted, and in the end the work was finished. Source：The Autobiography of Bertrand Russell, v.１, chap. 6: Principia Mathematica, 1967 More info.: http://russell-j.com/beginner/AB16-150.HTM
I used to stand on the footbridge at Kennington, near Oxford, watching the trains go by, and determining that tomorrow I would place myself under one of them. But when the morrow came I always found myself hoping that perhaps Principia Mathematica would be finished some day. Moreover the difficulties appeared to me in the nature of a challenge, which it would be pusillanimous not to meet and overcome. So I persisted, and in the end the work was finished.