> 2021年12月21日信息消化 ### [Against 3x Speed](https://perell.com/essay/against-3x-speed/) ([perell.com](https://news.ycombinator.com/from?site=perell.com)) > MEMO > > 真正的学习：意识到自己为什么而学，结合writing, spaced-repetition与实践。 [HN Link](https://news.ycombinator.com/item?id=29621642) > HN Command > @[zaptheimpaler](https://news.ycombinator.com/user?id=zaptheimpaler) That experience convinced me that your **internal assessment** of how well you understand something can be *wildly* off without an **objective yardstick**. Like nothing teaches epistemic humility quite as forcefully as getting rekt in an exam. Mike boastfully reads 100 books per year. He listens to audiobooks at 3x speed whenever he drives and swears he can remember it all. His browser has a plugin that lets him speed up YouTube videos, and for a while, he listened to podcasts on a special app because of its unique “Smart Speed” feature. All around, his strategy for learning is simple: shove as much information into the mind as possible. He’s one of those white-collar workers who’s always on the brink of quitting his job. He listens to podcasts while making pivot tables in Excel and stopped taking the subway to work because the train noise made it impossible to hear the audiobook narrators. During coffee breaks, he avoids conversation because he doesn’t like living life at “1x speed.” With a sped-up voice in his ear instead, he looks out of the 32nd floor of his company’s office and dreams of the day when he can finally quit his job and have the time to consume even more information. 200 books per year, he hopes. Despite all the information he’s sped through his ear, he’s never actually built anything. “Someday,” he insists. “Right now, I’m still learning.” I’m not constructing a strawman here. I know many people like Mike, and I used to be just like him. Mike is so busy preparing for the future that he never steps into it. The satisfaction of binge consumption brings instant gratification, so why try anything else? The problem is that shoving information into your mind can create the illusion of knowledge, especially when you rush it. True learning requires contemplation. And implementation. And a commitment to reflecting on great ideas over and over again. 迈克忙于为未来做准备，以至于他从未涉足。暴饮暴食的满足带来即时的满足，那么为什么要尝试其他的东西呢？问题在于，将信息塞进您的脑海中会造成知识的错觉，尤其是当您匆忙时。真正的学习需要沉思。和实施。并承诺一遍又一遍地反思伟大的想法。 Measuring your learning with a scorecard of consumption is anxiety-inducing. If you ground your identity in how much you’ve read, you’re always going to feel like a fraud because you’ll never be able to check every book off your want-to-read list. Plus, you can’t take action if you think you need to know everything about a topic before you step into the arena. 用消费记分卡衡量你的学习会引起焦虑。如果你把自己的身份建立在你读了多少书上，你总是会觉得自己像个骗子，因为你永远无法从你想读的清单上核对每一本书。另外，如果您认为在进入竞技场之前需要了解有关某个主题的所有信息，则您无法采取行动。 #### Mike’s Problem Listening to audiobooks at 3x speed is born out of a flawed model of learning — and it’s the same one that underpins our modern education system. The assumption is that people can acquire knowledge as if it’s a substance they can pour into their minds. I call it the **Water in a Cup method**—and anybody with a lick of common sense or the initiative to read a few research papers will see how misguided it is. In accordance with Adler’s assertion, two researchers from *Indiana University* [studied](https://ideas.time.com/2012/10/02/why-lectures-are-ineffective/) the ebbs and flows of students’ focus during a typical class period. They found that attention spans started to lapse after 10-18 minutes, no matter how good the teacher or how compelling the subject matter. After that, students’ attention would eventually return, but in briefer intervals each time. By the end of class, students could only stay focused for 3-4 minutes. Though this finding hasn’t been refuted, the implication of it — that long lectures aren’t an effective way to teach students — has been ignored by an educational establishment which still relies on lectures. 根据阿德勒的说法，印第安纳大学的两名研究人员研究了学生在典型课堂上注意力的起伏。他们发现，无论老师多么优秀或主题多么引人注目，注意力持续时间在 10-18 分钟后开始消失。之后，学生的注意力最终会恢复，但每次间隔时间较短。到下课时，学生只能集中注意力 3-4 分钟。尽管这一发现并未被反驳，但其暗示——长时间的讲座并不是教学生的有效方式——已被仍然依赖讲座的教育机构所忽视。 If we embraced the benefits of active learning, our classrooms would look nothing like they do today. The average classroom is set up for passive listening. It’s geared towards consuming knowledge, not integrating it. Desks are lined up in punitive rows that are designed to limit interaction between students. Subliminally, they say: “Shut up and listen to your teacher.” In my experience, lectures are most effective when they’re only a component of the classroom experience. In fact, two of the sharpest 15-year-olds I know, who attend one of the [best](https://alphaatx.medium.com/?p=c1016434cbd3) K-12 schools in the country, haven’t had a formal teacher since the 4th grade. My favorite college professor, Mrs. Cahill, saw how classrooms limited the integration of knowledge and rebelled against their architecture. We rearranged the entire classroom at the beginning of every class. That way, we could have the kinds of small group conversations that traditional classroom arrangements prevent. Her class was also less about consumption and more about conversation. Before arriving, we were responsible for reading 10 pages and writing a 750-word reflection on them. Class always began with small group conversations, in which we discussed the reading from the night before. **By ungrouping and regrouping into different groups, we gained different perspectives on the reading.** *Why do classrooms revolve around the water in a cup method?* Because the water in a cup method is easy to deliver and scale. Schools assume that learning is inevitable if students read enough books and spend enough time in the classroom. Systems are easy to scale when they use this reductive, cookie-cutter mindset. That’s why dates and key terms are bolded in textbooks and also the subject of exams at the end of the semester. But knowing the name of something without also understanding the context behind it isn’t knowledge. It’s trivia — and **[trivia](https://twitter.com/johnathanbi/status/1419080230552154113?s=21) is an ignorant person’s idea of what knowledge looks like**. **1** 学校认为，如果学生阅读足够多的书籍并在课堂上花费足够的时间，学习是不可避免的。当系统使用这种简化的、千篇一律的思维方式时，系统很容易扩展。这就是为什么日期和关键术语在教科书以及学期末考试的主题中加粗的原因。但是知道某物的名称而不了解其背后的背景并不是知识。这是琐事——而琐事是一个无知的人对知识是什么样子的看法。 A lecture-based class is predictable because you can prepare what you’re going to say in advance. As long as students remain in their seats, the teacher will feel like they’ve accomplished something, even if the students are just passing notes or picking their nose the entire time. Projects or Socratic discussions aren’t so simple. Since anything can happen when the students are in charge, the system doesn’t have the copy & paste repetition that industrial scale systems demand. Plus, the establishment says, if you’re a teacher, isn’t it your job to deliver information? No. Your job is to make sure they learn. That process is accelerated when you move beyond the “Water in a Cup” theory of learning. 基于讲座的课程是可以预测的，因为您可以提前准备要说的内容。只要学生留在座位上，即使学生一直在传递笔记或挖鼻孔，老师也会觉得他们完成了某件事。项目或苏格拉底式讨论并不那么简单。由于当学生负责时任何事情都可能发生，因此该系统没有工业规模系统所需的复制和粘贴重复。另外，该机构表示，如果您是一名教师，那么提供信息不是您的工作吗？不。你的工作是确保他们学习。当您超越“杯中水”的学习理论时，这个过程会加速。 #### The Alternative The smartest people I’ve met reject the “Water in a Cup” theory. They focus less on consuming as much information as possible and more on **cultivating the deepest possible understanding of the ideas that resonate with them most.** Their neverending springtime harvest reminds me of the way my approach to travel changed after some trial and error. I once went on a month-long Euro Trip during which I tried to visit as many cities as possible. In four weeks, I visited Amsterdam, Berlin, Prague, Vienna, Budapest, Interlaken, Innsbruck, and Salzburg. My goal of visiting as many cities as possible was the “Water in a Cup” theory applied to travel. Though I got to survey these cities, my international game of hopscotch made it hard to cultivate meaningful experiences. By the time I’d build an emotional attachment to a city or somebody who lived there, it was time to pack my bags. Upon returning home, I vowed to avoid trips like that in the future. Instead, I vowed to spend more time in the cities I visited. 他们永无止境的春季收获让我想起了经过反复试验后我的旅行方式发生了变化。我曾经进行了为期一个月的欧洲之旅，在此期间我尝试访问尽可能多的城市。在四个星期内，我访问了阿姆斯特丹、柏林、布拉格、维也纳、布达佩斯、因特拉肯、因斯布鲁克和萨尔茨堡。我访问尽可能多的城市的目标是将“杯中水”理论应用于旅行。虽然我必须调查这些城市，但我的国际跳房子游戏让我很难培养有意义的体验。当我对一个城市或住在那里的人建立情感依恋时，是时候收拾行李了。回到家后，我发誓以后避免这样的旅行。相反，我发誓要在我访问过的城市中花更多的时间。 **The meaningful parts of a culture, like books, only show up when you give them time. They hide parts of their personality and only reveal themselves once you stop, slow down, and commit to them for a little while.** 文化中有意义的部分，比如书籍，只有在你给它们时间时才会出现。他们隐藏了他们个性的一部分，只有在你停下来、放慢脚步并承诺一小会儿时才会显露自己。 In school, writing essays was the closest I got to that deeper experience. If going 3x speed is like country-hopping, writing an essay is like being an expat. When you write your essay, you’re effectively saying: “This is my intellectual home for the next little while.” It’s the opposite of the intellectual nomading that’s become so popular. To that end, schools are right to see essay writing as one of the most effective methods of learning. Syllabuses, too, are useful because they force you to focus on a single topic for longer than you naturally would. #### Spaced Repetition The research on spaced repetition shows that listening to audiobooks at 3x speed is a terrible way to retain information. In fact, it’s the opposite of what you should do. If you want to retain information, **you should review the stuff you’ve already read.** Spaced repetition yields **exponential benefits** for increased effort. So, at least at first, **you gain more from a piece of information every time you return to it.** Your ability to remember something improves every time you review it, and the more you do it, the less time it takes to do so. Taken all together, racing through ideas at 3x speed is precisely the opposite of what the research says you should do. At the risk of oversimplification, humans have two kinds of memory: short-term and long-term. When you read books at 3x speed, you make it hard for your mind to transfer knowledge to long-term memory, which is more stable and lasting than short-term memory. Though brain scientists are still learning how this process of consolidation happens, researchers like Eric Kandel have written: “For a memory to persist, the incoming information must be thoroughly and deeply processed.” The science of memory reveals why writing is such an effective way to learn. **Putting ideas into your own words forces you to internalize them.** Rather than memorizing disparate pieces of information, writing helps you deduce their logic and bring them together into a coherent whole. Moreover, the process of brainstorming, typing, and editing our words acts like spaced repetition. Taken all together, a systematic implementation of spaced repetition may be the lowest hanging fruit in education right now — and it’s the opposite of the “Water in a Cup” method of learning. #### Direct Experience There’s a whole level of knowledge, most of which is hard to define, that only reveals itself once you step outside the classroom and actually do the thing. I’ve always liked the idea that in theory, there’s no difference between theory and practice. But in practice, there is. That’s why, even when it’s logically sound, academic knowledge often falls short when people try to implement it. 有一个完整的知识水平，其中大部分很难定义，只有当你走出教室并实际做这件事时才会显现出来。我一直喜欢这样的想法，即理论上，理论与实践之间没有区别。但在实践中，有。这就是为什么，即使它在逻辑上是合理的，但当人们试图实施它时，学术知识往往不足。 Language learning provides another example. You can pick up trivial knowledge by banging your head against a classroom wall for 10 years. Or, you can immerse yourself for a year and walk away fluent. Conversations with native speakers are far more effective than learning in a classroom. 语言学习提供了另一个例子。你可以通过用头撞教室墙 10 年来获取琐碎的知识。或者，您可以让自己沉浸一年，然后流利地离开。与母语人士的对话远比在课堂上学习有效。 Lectures shouldn’t be the main event. Same goes for anything that resembles a lecture, like an audiobook. When it comes to language learning, you aren’t fluent when your grammar is perfect. You’re fluent when you can joke around using slang and other colloquialisms. Usually, that means you’re no longer translating words from your native language before you say them. You’re not thinking about grammar or pronunciation either. Everything flows together. The vast majority of language speakers can only reach this kind of fluency once they’ve immersed themselves in the day-to-day realities of a foreign culture. 讲座不应成为主要活动。任何类似于讲座的东西也是如此，例如有声读物。在语言学习方面，如果你的语法很完美，你就不会流利。当你可以用俚语和其他口语开玩笑时，你就很流利了。通常，这意味着您在说出之前不再翻译来自母语的单词。你也没有考虑语法或发音。一切都一起流动。绝大多数语言使用者只有将自己沉浸在外国文化的日常现实中才能达到这种流利程度。 #### An Alternative to 3x Speed It’s okay to not know everything. The world rewards people who develop expertise in a specific subject. When that expertise is unique, **it’s developed through direct experience and deliberate reflection**. Mike should study the meta-practice of learning itself and embrace a model of learning that respects the limitations of the human mind. The water in a cup theory is a false, robotic assumption that was instilled in us, wrongly, by an archaic education system. Newsflash: Mike is a human, not a computer. He needs time to synthesize what he reads and transfer knowledge from short-term to long-term memory. **He should think more strategically about what he wants to learn and why.** By learning at a more human speed, he can spend more time integrating knowledge. Racing through audiobooks isn’t helping Mike as fast as he thinks. **He’ll serve himself far better by slowing down and embracing the triad of writing, spaced repetition, and direct experience.** 迈克是人，不是电脑。他需要时间来综合他阅读的内容并将知识从短期记忆转移到长期记忆。他应该更有策略地思考他想学什么以及为什么学。通过以更人性化的速度学习，他可以花更多时间整合知识。通过有声读物赛跑并没有像他想象的那样快速帮助迈克。通过放慢速度并接受写作、间隔重复和直接体验的三位一体，他会更好地为自己服务。 ### postgres psql [psql-tips.org](https://psql-tips.org/psql_tips_all.html) If you want to simply **send** a single line command to psql **and** **exit**, try using the `-c` or `--command=command` flag. ```bash laetitia:~$ psql -c 'select * from test;' id | value ----+------- 1 | test (1 row) ``` You can combine several `-c` or `--command=command` flags to **execute several commands** or queries. ```bash laetitia:~$ psql -c 'select count(*) from test;' -c 'select * from test;' count ------- 1 (1 row) id | value ----+------- 1 | test (1 row) ``` With the `--csv` flag, psql will display the result as a **csv** file. ```bash psql --csv -c 'select * from test;' id,value 1,test ``` The `-E` or `--echo-hidden` will display the actual query generated by backslash commands. It is a great way to learn Postgres and psql internals. ```bash laetitia:~$ psql -E -c '\l' ********* QUERY ********** SELECT d.datname as "Name", pg_catalog.pg_get_userbyid(d.datdba) as "Owner", pg_catalog.pg_encoding_to_char(d.encoding) as "Encoding", d.datcollate as "Collate", d.datctype as "Ctype", pg_catalog.array_to_string(d.datacl, E'\n') AS "Access privileges" FROM pg_catalog.pg_database d ORDER BY 1; ************************** List of databases Name | Owner | Encoding | Collate | Ctype | Access privileges -----------+----------+----------+-------------+-------------+----------------------- laetitia | laetitia | UTF8 | en_US.UTF-8 | en_US.UTF-8 | postgres | postgres | UTF8 | en_US.UTF-8 | en_US.UTF-8 | template0 | postgres | UTF8 | en_US.UTF-8 | en_US.UTF-8 | =c/postgres + | | | | | postgres=CTc/postgres template1 | postgres | UTF8 | en_US.UTF-8 | en_US.UTF-8 | =c/postgres + | | | | | postgres=CTc/postgres test | postgres | UTF8 | en_US.UTF-8 | en_US.UTF-8 | (5 rows) ``` Use `-f filename` or `--file=filename` to play queries from a **file**. ```bash laetitia:~$ cat query.sql select * from test; laetitia:~$ psql -f query.sql id | value ----+------- 1 | test (1 row) ``` If you use the value `-` (hyphen) in the flag `-f` or `--filename`, psql will read commands and queries from the standard input. The read will end when reaching EOF command (CTRL+D) or the `\q` command. ```bash laetitia:~$ psql -f - laetitia=# select * from test; \q id | value ----+------- 1 | test (1 row) ``` You can give queries to psql from the standard input using `< filename`. You can use the result of another command as an input for psql using the `|` character. ```bash psql < query.sql cat query.sql | psql ``` Connect to DB ```bash # available since Postgres 8.3. psql -d "host=localhost port=5432" psql testdb psql -d testdb export PGDATABASE=testdb;psql ``` You can use the `-h hostname` or `--hostname hostname` flag to provide the directory the server is writing the into, instead of providing a hostname. ```bash laetitia:~$ sudo grep unix_socket_directories /usr/local/pgsql/data/postgresql.conf unix_socket_directories = '/tmp' # comma-separated list of directories laetitia:~$ psql -h /tmp psql (14devel) ``` Use the `-H` or `--html` flag to get the query result in HTML format. ```bash psql -H -c 'select * from test;' ``` The `-l` or `--list` flag will list the databases available on the server. ```bash psql -l ``` The `-o filename` or `--output=filename` flag will write all query output into file filename. ```bash laetitia:~$ psql -c 'select * from test;' -o output.log ``` psql will be more quiet with the `-q` or `--quiet` flag on. ```bash psql -q ``` If you want to debug a script, the `-s` or `--single-step` flag will make psql stop after each command. ```bash psql -s -f query.sql ``` You can use variables in psql in non-interactive mode. the flag `-v assignment` or `--set=assignment` or `--variable=assignment`. ```bash aetitia:~$ cat query.sql select * from :tablename; laetitia:~$ psql -v tablename=test -f query.sql aetitia:~$ cat query2.sql select * from test where value = :'var'; ilaetitia:~$ psql --set var=test -f query2.sql psql -v var=value -c '\echo :var' ``` in interactive mode, you can connect to a different database with the metacommand `\c dbname` or `\connect dbname` ```bash laetitia=# \conninfo You are connected to database "laetitia" as user "laetitia" via socket in "/tmp" at port "5432". # You can display copyright information and distribution term of PostgreSQL by using the \copyright metacommand. laetitia=# \copyright # The \cd metacommand will change the current working directory. laetitia=# \cd /tmp laetitia=# \! pwd ``` `\db` will display a list of tablespaces. `\db pattern` will list tablespaces matching the pattern. The `+` modifier will display access privileges, options, size and description. ```bash aetitia=# \db List of tablespaces Name | Owner | Location ------------+----------+---------- pg_default | postgres | pg_global | postgres | (2 rows) laetitia=# \db+ List of tablespaces Name | Owner | Location | Access privileges | Options | Size | Description ------------+----------+----------+-------------------+---------+--------+------------- pg_default | postgres | | | | 39 MB | pg_global | postgres | | | | 559 kB | ``` `\copy ... to ...` will allow you to copy data to a file on the client host. ```bash laetitia=# \copy (select * from test) to mydata.dmp COPY 2 laetitia=# \! cat mydata.dmp 1 test 5 blabla ``` `\copy` will allow you to copy data from something into a table (something might be the result of a command, a program, stdin...) ```bash laetitia=# \copy test(value) from stdin Enter data to be copied followed by a newline. End with a backslash and a period on a line by itself, or an EOF signal. >> value1 >> value2 >> \. COPY 2 laetitia=# select * from test; id | value ----+-------- 1 | test 5 | blabla 6 | value1 7 | value2 (4 rows) ``` `\copy` is less efficient than the SQL command `copy` because all data must pass through the client/server connection. For large amount of data, the SQL command is better. - The `\dx` metacommand will display a list of installed extensions. `\dx pattern` will display only extensions matching the given pattern. The `+` modifier will allow to display a list of all the objects belonging to each extension. - `\du` will display a list of users. Remember that since Postgres 8.1, users and roles are the same thingi (see [Postgres documentation](https://www.postgresql.org/docs/current/user-manag.html))). - The `\e` (or `\edit`) will open the current querry buffer into the default editor (or the editor set by the `PSQL_EDITOR`, the `EDITOR` or the `VISUAL` variables. - You can open a file under psql using the `\e filename`. The file will open in the editor and after saving and exiting the editor, the content of the file will be copied into the query buffer. ### Misc - [v2ex](https://www.v2ex.com/t/823282) | 每当有”老板“质疑我用的技术够不够高端，性能够不够强大的时候，我都跟他说：如果我做的这套系统跑不动你的业务了，那说明你已经发大财了，那时候已经有足够的钱请更牛逼的人来升级这个系统。 通常他们都会很满意，同时很期待我这个系统早一点跑不动 - **Brewster Kahle** | Internet Archive - the internet’s chief librarian - [The story of the fight to archive the internet](https://www.techradar.com/news/the-story-of-the-fight-to-archive-the-internet?utm_source=tldrnewsletter) > Since its conception, the Internet Archive has amassed an impressive 70 petabyte (70,000 terabyte) library of content, comprising 635 billion webpages, but also 34 million books, 14 million audio recordings and more. - **Communication Platforms** ｜ David Perell Every communication platform teaches a different lesson: - Twitter: Cut the fluff - YouTube: People love a good narrative - TikTok: Nail the hook - Instagram: Make it beautiful - Email: Whatever you’re saying, shorten it