对付一个不自由的世界的唯一方法是变得如此绝对自由，以至于你的存在本身就是一种反抗。

可持续性不是一种选择；而是我们对后代的责任。

Adaptability is the most important skill in today's rapidly changing world.

We begin with the hypothesis that any subject can be taught effectively in some intellectually honest form to any child at any stage of development.

定义就是限制。