在数学中，提出问题的艺术必须比解决问题更有价值。

I would like to fly in space.Absolutely.That would be cool.I used to just do personally risky things， but now I’ve got kids and responsibilities， so I can’t be my own test pilot.That wouldn’t be a good idea.But I definitely want to fly as soon as it’s a sensible thing to do.

真理是时间的孩子，而不是权威的孩子。