在一个不自由的世界里，唯一的应对方式就是变得如此绝对自由，以至于你的存在本身就是一种反叛。
The only way to deal with an unfree world is to become so absolutely free that your very existence is an act of rebellion.
You can never know anyone as completely as you want.
——《在广州中国国民党恳亲大会的演说》（1923年10月15日）
"The world is full of obvious things which nobody by any chance ever observes."
The challenge in model checking is not just to find errors, but to understand why they occur.