人类不仅是自然的产物,也是自然的改造者,常常带来不可逆转的后果。
"Man, unlike any other thing organic or inorganic in the universe, grows beyond his work, walks up the stairs of his concepts, emerges ahead of his accomplishments."
If you're not stubborn, you'll give up on experiments too soon. And if you're not flexible, you'll pound your head against the wall and you won't see a different solution to a problem you're trying to solve.
The concept of NP-completeness has provided a powerful tool for understanding the complexity of problems.