纯数学在某种程度上是逻辑思想的诗歌。
Pure mathematics is, in its way, the poetry of logical ideas.
心理学必须基于可观察的事实,而非推测。
最好的儿童书籍是那些不会居高临下地对孩子说话的书籍。
The behaviorist asks: Why don't we make what we can observe the real field of psychology?