暗时间

by 刘未鹏

《暗时间》是从刘未鹏8年的博客文章中精选出来的，主要关于心智模式、学习方法和时间利用，《暗时间》的书名便来自于此。刘未鹏说——写博客这件事情给我**的体会就是，一件事情如果你能够坚持做8年，那么不管效率和频率多低，*终总能取得一些很可观的收益。

Unknown Binding

Reviews

[Barack Liu · Rating 5 out of 5]

568-Dark Time-Liu Weipeng-Essay-2011

Barack
May 2nd , 2025

Dark Time was first published in 2011. In 2003, Liu Weipeng published his first article in a magazine and started blogging. The initial blogs were short and trivial, and were interspersed with some translated articles. Later, he gradually began to have some of his own experiences and opinions. Overall, in the past 8 years, the author has written an average of 1 blog or less per month, but has never stopped. Liu Weipeng said that the biggest experience I have gained from blogging is that if you can persist in doing something for 8 years, no matter how low the efficiency and frequency are, you will always get some considerable benefits in the end. Another experience is that as long as you persist in doing something long enough, "persistence" will slowly become a "habit." Things that originally required effort to drive have become commonplace and easy. This book is a selection of Liu Weipeng's blog posts over the past 8 years.

Liu Weipeng, a master's degree holder in computer science from Nanjing University, currently works at the Innovation Engineering Center of Microsoft Research Asia. He is the founder of the famous comprehensive technology discussion group Toplanguage .

Table of Contents
1. Dark time
2. My seven years at Nanjing University
3. Some learning habits that have always accompanied me (I): learning and thinking
4. Some study habits that have always accompanied me (Part 2): Time management
5. Some study habits that have always accompanied me (Part 3): Reading methods
6. Some of my learning habits (IV): Knowledge structure
7. Read and think
8. How to think clearly (a summary of my spare time reading on thinking)
9. Escape from Your Shawshank (Part 1): Why do you have to experience it yourself to understand it?
10. Escape from Your Shawshank (Part 2): Different people have different opinions? From optical illusions to prejudices
11. Escape from Your Shawshank (Part 3): Meet Yourself 200,000 Years Ago
12. Escape from Your Shawshank (IV): Sense and Sensibility
13. Escape from Your Shawshank (V): Invisible Cage (Part 1)
14. [ BetterExplained ] Why you should start blogging (right now)
15. [ BetterExplained ] Why you should do it yourself when you encounter a problem
16. [ BetterExplained ] Writing is for better thinking
17. [ BetterExplained ] Conflict Resolution in Intimate Relationships
18. [ BetterExplained ] How to memorize and learn effectively
19. C++11 (and modern C++ style) and rapid iterative development
20. How to spend two years interviewing someone
21. Knowing the reasons (Part 3): Why are algorithms so difficult?
22. Know the Reason (Continued)
23. Not a book review: I am an it little bird
24. What are the first principles of programming?
25. Independence Day
26. Hammer and Nail
27. What is your irreplaceable and core competitiveness?
28. Methodology, Methodology - Programmer's Achilles' Heel
29. The Beauty of Mathematics: The Ordinary and Magical Bayesian Method
30. Machine Learning and Artificial Intelligence Learning Resource Guide
31. Understand the reasons (taking algorithm learning as an example)
32. The Beauty of Mathematics: Why is Quicksort so fast?
33. Learning and Memory
34. Learn to solve problems from Polya (rev#3)
35. Failing To See the Big Picture – Mistakes we make when learning programming
36. The Beauty of Mathematics: Probability Theory in Evolution
37. Learning density and concentration
38. Cantor, Gödel, Turing - The Eternal Golden Diagonal (rev#2)

Each of us has an extremely important but often overlooked asset, which is time. Just as we tend to pay more attention to physical health and ignore mental health, time is easily underestimated by us partly because of its abstractness. In contrast, money is a more quantifiable resource - you can clearly know how much money you spent and how much money you made today; while the passage of time is often silent and difficult to grasp, so it is more likely to be wasted unconsciously. One of the author's core points is that the large amount of "hidden time" we spend in daily life actually contains the possibility of being used efficiently. The so-called "dark time" refers to those fragmented periods of time in doing housework, commuting, walking, washing and other affairs - although they are scattered, they almost permeate every corner of our lives. If we can consciously transform this time into thinking time and ideation time, it is possible to accumulate the results of deep thinking without taking up an extra block of the schedule. Of course, if we choose to simply enjoy the present moment while eating without thinking, that is completely fine. Time itself is a luxury, and pure relaxation and focusing on the present life are also a high-quality existence. But if we are in an urgent state of "wanting to accomplish something important", but often feel that we don't have enough time, then we need to optimize the calculation of "time area". The total value of completing a thing is like calculating an area. It has two dimensions: one is the time investment, and the other is the efficiency. When many people mention "hard work", they often only refer to spending a lot of time, but ignore efficiency. For example, if we spend half an hour every day doing a job that we are not good at, do not love, or even reluctant to do, even if we accumulate 2,000 hours a year, after thirty years, it may be nothing more than mediocrity and wasting time. The truly efficient use of time does not lie in "doing things for a long time", but in "doing what you are willing and good at with high quality". Further reflect on the time-consuming but often ignored parts of our daily lives, such as cooking, commuting, washing clothes, cleaning, etc., these things together actually account for an astonishing proportion of our lives. If these chores can be centralized and the process can be simplified, a large block of time can be left for truly important things. In this way, a whole block of time can be set aside for activities that require high concentration, such as reading, writing, and creation. In addition, we should also reduce the frequent switching between tasks. The brain is like a computer. Frequent "loading" and "unloading" of different types of tasks will bring huge switching costs. If we keep jumping between different tasks every day, it will not only lead to distraction, but also may form continuous mental fatigue. Therefore, it is the key to improve efficiency to arrange the types of tasks reasonably and concentrate on similar matters. For example, after get off work, can we focus on an important personal plan? For example, writing, in-depth reading, project review, etc., all require a whole period of time to support, so that it is easy to enter the "flow" state. Of course, there are some things that do not require high thinking, but emphasize the body's "muscle memory", such as playing guitar, dancing, practicing typing, etc. This type of task has little to do with the mental load, and is suitable for "one step a day" type of practice. Arrange a small period of time every day, and the key is persistence. In general, we should adapt to the type of task: for things that require in-depth thinking, a whole block of time should be set aside; muscle memory tasks are suitable for fragmented distribution. In this way, not only can efficiency be improved, but also real compound growth can be achieved on the intangible asset of time.

Some people say that excellence is a habit. The author shared two key habits that he developed under the influence of his father in his childhood: the first is to maintain a strong curiosity about new things, and the second is to take the initiative to learn when encountering problems that he does not understand, especially to solve them through reading and self-study. It is these two habits that made him have a strong interest in computers before going to college. With this interest, he not only systematically studied many computer-related courses during his undergraduate studies, but also spontaneously did a lot of extracurricular projects. At the same time, he insisted on writing blogs and actively expressed and communicated on the Internet. It is worth noting that these behaviors did not have clear goals at the time, and there was no immediate return, but he continued to do them. This behavior of "still choosing to invest without knowing the results" also reflects his passion. After entering the graduate stage, his life faced a turning point between graduation and work, so his goals became clearer, and the rhythm and structure of learning became tighter and more planned. During this period, he systematically consolidated his basic abilities. The author mentioned that he tried to apply for Microsoft Research Asia in his undergraduate studies but failed, and tried again in the graduate stage and finally succeeded in entering. This is not only a microcosm of personal growth , but also confirms an important principle: when you really want something, you will keep trying until you get close to it. There is a saying called "the law of attraction". On the surface, it seems like a kind of metaphysics; but if you understand it from a rational perspective, it is actually very logical: when a person has a strong desire for something, even if he fails the first time, he will persist in the second and third time until he succeeds. This persistence and enthusiasm itself constitutes attraction. We should start from ourselves and think seriously: What do I really want? What is the thing that I am willing to stay up all night and dream about? For the author, it is programming, technology, and blogging; but for others, it may be music, dance, art, literature... Everyone's source of passion is different. The key is to find the direction that makes you willing to invest time, try and fail repeatedly, and enjoy it. The so-called "those who learn from me live, and those who imitate me die." Don't imitate other people's specific paths, but learn their spirit and methods. Instead of asking "what specific things he did, I will do it too", it is better to think "why can he persist in doing this? What internal drive does he rely on?" What is really worth learning is not what he did, but "how he became such a person."

The book Dark Time is essentially a record of the author's fragmentary thoughts, a kind of expression of fragmentary thoughts. This kind of short sentences, fragments, and introspective texts resonate deeply with me. I started to record this kind of "fragments of thoughts" as early as 2013. I may not have realized their value at that time, but looking back, these seemingly scattered words constitute an important trace of my ideological growth. Many ideas in the book are not so-called "original" or "unprecedented" insights. They are often based on the author's past reading, memory and life experience, and are seeds that germinate in the soil of other people's thoughts. Only when a person can express these ideas without a manuscript and organize them in his own language, these ideas truly "belong" to him. Language is not only a tool of expression, but also an internalization of thought. The real "mastery" is not to memorize those golden sentences by rote, but to be able to switch languages and flexibly express the same connotation. It is easy to look at the "golden sentences" summarized by others, but the key is: can you do it? If you only remember those principles but cannot put them into action, they will still be "someone else's stuff" and no matter how good they are, they cannot be transformed into your own strength. On the contrary, even if you only practice a small principle, as long as you persist, it may have a profound impact over time. Therefore, the key to the problem has never been "how many books have you read" or "how many famous quotes have you remembered", but: how much knowledge have you turned into your actions? Most people believe that "early to bed and early to rise is good for health", but it is useless to tell yourself a hundred times a day. Only when you really go to bed and get up early can this principle be considered "living in you". We often say that "ruthless people don't talk much". What is "ruthless"? It's not about shouting slogans loudly, but about your ability to quietly do things that others can't do. This ability is accumulated by action, not by plans and wishes. What you do specifically may not be that important. Just like when we choose university majors and plan our life paths, we always want to choose "popular" and "promising" directions, but are these choices really suitable for you? If you don't like this direction, you won't be passionate and efficient in doing it. On the other hand, even if you choose a "non-mainstream" or "unpopular" direction, as long as you really love it, are willing to invest in it, and are willing to ponder and persist, then you will naturally develop a whole set of matching good habits. A road that was originally not optimistic can also be made smooth by you.

The author believes that we should read with questions in mind in order to truly learn something. This reminds me of a sentence in The Analects: "If you are not angry, you will not be enlightened; if you are not frustrated, you will not speak out; if you do not use the three corners to reflect on one corner, you will not be able to learn again." This means that only when a person has exhausted his own thinking and attempts, but still cannot solve the problem and is eager for the answer, can the guidance from the outside world be truly effective. This way of reading "looking for answers with questions" is essentially a learning path of active exploration. I myself had similar experiences when doing questions in high school. Sometimes, in order to save trouble, I would skip the thinking process directly and look at the reference answers after reading the questions. At that time, I looked at the clear and organized ideas of the answers and thought that it was just so-so. But if you let me solve it again from the beginning, I often can't write it out. But if I have done 90% of the process myself, and only the last step is left, when I look at the answer again, the feeling of "sudden enlightenment" is the real learning. This experience also made me reflect: the key to learning is not "understanding", but understanding after "participation" and "struggle". In addition to how to read with questions, the author also mentioned a practical technique: read the most important part of a book first. This is actually somewhat different from my reading habits. I used to read a book from beginning to end, and even if I found it inappropriate to read later, I would still insist on finishing it. The author advocates "skipping reading", that is, first confirm what problem you want to solve, and then select the most relevant 10% of the book to read, so that you can solve practical problems more targeted. In comparison, I found that my reading method can indeed be further optimized: instead of "reading a book" in form, it is better to "solve a problem" in essence. Another point that impressed me was: how to choose a book worth reading. The author recommends judging based on reader reviews, and especially emphasizes the reference value of "negative reviews" - if a book's negative reviews lack substantive criticism, it often means that the book does not have much problem; but if the negative reviews contain in-depth, specific, and organized criticism, then the book is likely to have major flaws. This method is more systematic and rational than my previous reliance on friends' recommendations. Of course, I have to admit that books recommended by friends can sometimes bring unexpected surprises. It often breaks away from my existing reading preferences and takes me into areas that I would not have actively contacted. I once read a book that was completely beyond my interest because of a friend's casual remark "You should like this book", but I gained a lot from it. So now I feel more and more that a good recommendation is not just telling you "what you will like", but guiding you to think about "what else you might like". Finally, regarding the two ways of acquiring knowledge, "reading" and "watching videos", in comparison, reading gives me more space to pause and think. I can underline, recall, and reread at any time, which is suitable for slow internalization. Although the video is fast-paced and highly operational, it is not easy to settle. Both have their advantages and disadvantages, and the key is to see what kind of tasks we use it to complete.

According to this book, the author's reading volume is amazing, but time is limited after all. To achieve such a high reading output, the core lies in two aspects: one is where to "squeeze" enough time to read, and the other is how to improve the efficiency of reading itself. The acquisition of time is the origin of the title of this book, "Dark Time". The author advocates making full use of those seemingly fragmented time in life - such as walking, riding, and queuing - these times that were originally used for "corner entertainment" are converted into reading time. For example, he would read while walking and read while waiting for the bus. This reminds me of my experience of reading comics in junior high school. I always lowered my head to read on the way from home to school. However, looking back now, I don't think this is the most efficient way. Because reading in an unstable and distracted environment often "seems to be reading", but it is actually difficult to deeply absorb the content. In comparison, I now prefer to concentrate on doing one thing: instead of reading while walking on the road, it is better to walk this section of the road quickly, really "squeeze" out the time, and set aside a whole period of time for immersive reading. Compared with the "toothpaste-squeezing" fragmented time, more quality whole blocks of time often bring higher concentration and comprehension. In terms of reading efficiency, the author proposed a method worth learning from: first read the table of contents, establish an overall understanding of the structure of the whole book, and then choose chapters to focus on reading according to your own needs and interests. This method breaks the tradition of mechanical reading from beginning to end, and instead emphasizes goal orientation and selective absorption. Unless it is a work such as novels that emphasize coherence, most reference books and knowledge books can actually be handled by "skipping" and "deep reading of key points". I realized that in my past reading habits, I was indeed to

[BIN LI · Rating 5 out of 5]

读《暗时间》学习到了很多学习技巧和思维方式，因为正巧也是程序员，所以对刘未鹏的涉猎之广更加钦佩。现在的互联网公司大多数在压榨程序员劳动力，在高压工作下还能充实自己的人其实没有特别多，挣钱买房养家是第一要务。能抽出时间来丰富自己，提升自己，并且能够深入思考践行的，更是少数了。一直以来我也非常喜欢心理学，但是买了挺多大部头，一直也没有下定决心完整啃下来，看《暗时间》又一次激发了我读这些书的兴趣，实在有太多有趣的东西值得去学习，值得去思考和实践。

[Cleamoon · Rating 4 out of 5]

内容有些杂但很不错。引申知识很多，都看下来需要很多时间。作为扩展阅读目录不错。

[Mr.Shore · Rating 4 out of 5]

作者涉猎之广让我十分震惊，虽然这本书的内容有点杂乱，但作为另一个的程序员，我还是被这种孜孜不倦的探索打动了，希望我也可以成为这样的人。

[东海帝宝 · Rating 5 out of 5]

it inspired me when i was a child

[麗瑩 · Rating 3 out of 5]

It’s like a personal keep-sake notebook from a CS graduate student. I think I read it just to make sure that I still understand these somewhat solid things (not the math part).

[Zining · Rating 4 out of 5]

This book contains a lot of blogs of the author from MindHacks. A few categories worth noting down include:
- Studying habits
- Time management
- Reading methods
- Memorization. In this part the author uses his experience to talk about various techniques of reinforcing memory including teaching, abstraction, experience virtually, and relating to our experiences.
- Critical thinking and problem solving
On the other hand, since this book is the blog of the author, it does not organize the information like a textbook. So I would not put this book as a "textbook" for any of the above-mentioned fields. There are plenty of books in each of these fields with better study paths.

[Susie · Rating 5 out of 5]

This is an amazing book. Previously I stopped halfway because the fourth part of the book is about programming and mathematics, which I am not good at at all. However, I resumed reading this book and found the fourth part even excellent. The book is showing you how people/ we think and solve problems. Highly recommend this book.

[Kevindreamfly · Rating 5 out of 5]

读来最有收获的一本书。在认知层面有了一次大清洗，另外，也从中印证了许多我自己一直认同的观点，比如：书写是一种极为有效的思考方式。