The mind is a constantly unfolding process.

【译文】 孔子说：“温习旧知识时，能有新收获，就可以做老师了。”

I went to the woods because I wished to live deliberately. I wanted to live deep and suck out all the marrow of life, to put to rout all that was not life.

科学的真正回报是理解新事物的兴奋感。

没有牺牲，就没有自由。