Abstraction allows for a kind of freedom that representation sometimes doesn't.

One’s attitude to oneself is the single most important factor in living a long and reasonably happy life.

"The truth is rarely pure and never simple."

Each of us is an island, but we can connect through bridges.

我们从这样的假设开始：任何学科都可以以某种智力上诚实的形式有效地教给处于任何发展阶段的任何孩子。