因果推断的本质是超越数据，询问如果我们干预会发生什么。

未经审视的生活不值得过。

我总是感到，生活就象萌发于地下根茎的植株。生活的真正生命是不可见的，它深藏于地下根茎中，而显露出地面的可见一斑部分只能生存一个夏季。我们所见到的是将会消逝的花簇，而根茎长驻。

You put together two people who have not been put together before; and sometimes the world is changed, sometimes not. They may crash and burn, or they may ignite and light up the sky.

逻辑学研究不仅仅是关于形式系统，而是理解理性思维的基本结构。

Courage is what it takes to stand up and speak; courage is also what it takes to sit down and listen.