看一遍不如说一遍，说一遍不如做一遍

很早以前我就知道有一种学习方法叫费曼学习法，这种方法强调的学习方式是输出式学习。简单来讲就是假设你身边存在一个对这方面知识完全不了解的朋友，你通过向他讲解你学习到的知识，从而巩固自己的学习成果。一开始我只是对这种学习方法有所耳闻，并没有真正付出时间去尝试。《道德经》说：上士闻道，勤而行之；中士闻道，若存若亡；下士闻道，大笑之。不笑不足以为道。更是强调了那些优秀者强于普通人的特点：听到有用的道理，就会去立即践行，而不是只是过过耳朵。我这段时间才有对这句话的深刻体会，有的时候学习过的代码如果不关上书自己敲一遍，自己是永远不会掌握的；有些时候看过一本小说，突然回忆起这本小说讲了什么故事，我有的时候连人名都念不全，这是因为自己在阅读的时候无意间跳过了很多内容，造成了自己吸收到“知识”的假象。

真正掌握知识，只有做一遍这一种方法。只有做一遍，才能发现原有学习到的知识有多少纰漏。自己其实还有多少没搞懂的地方。看是有信息损失的，只有做一遍才能学到真东西。怪不得古话说，是骡是马，拿出来遛遛。

Reading once is not as good as saying it once, and saying it once is not as good as doing it once.

I knew a long time ago that there is a learning method called the Feynman Learning Method. This method emphasizes output - based learning. Simply put, assume that there is a friend around you who knows nothing about this knowledge. By explaining the knowledge you’ve learned to him, you can consolidate your learning achievements. At first, I only heard about this learning method and didn’t really spend time trying it. The “Tao Te Ching” says: “The superior man, when he hears of the Tao, earnestly carries it into practice. The mediocre man, when he hears of the Tao, seems now to keep it and now to lose it. The inferior man, when he hears of the Tao, laughs loudly at it. If he did not laugh, it would not be fit to be the Tao.” This further emphasizes the characteristic that outstanding people are superior to ordinary people: when they hear useful principles, they will immediately put them into practice instead of just listening. I have only deeply understood this sentence recently. Sometimes, if I don’t close the book and type the learned code myself, I will never master it. Sometimes, after reading a novel, when I suddenly recall what story the novel told, I can’t even fully pronounce the names of the characters sometimes. This is because I unconsciously skipped a lot of content while reading, creating the illusion that I had absorbed “knowledge”.

The only way to truly master knowledge is to do it once. Only by doing it once can you find out how many flaws there are in the originally learned knowledge and how much you actually haven’t understood. There is information loss in just reading. Only by doing it once can you learn something real. No wonder the old saying goes, “You’ll know if it’s a mule or a horse by taking it out for a walk.”