Monthly Archives: May 2013

SICP, 3

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Just as every day thoughts are expressed in natural language, and formal deductions are expressed in mathematical language, methodological thoughts are expressed in programming languages. A programming language is a method for communicating methods, not just a means for getting a computer to perform operations – programs are written for people to read as much as they are written for machines to execute.

— Lisp: A language for stratified design

— Harold Abelson, Gerald Jay Sussman

— SICP distilled

— jao 

2013.05.31 Friday ACHK

Consciousness | 自我 | 意識

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There is no direct self-interaction.

An observation or measurement is an interaction between the observer and the observed, involving two objects. So there is logically impossible to have direct self-observation.

— Me@2013-05-29 12:09:46 AM

You cannot see yourself directly from your own point of view. Instead, you can only see your mirror, photo, and video images. In other words, you can only indirectly see yourself.

— Me@2013-01-20 01:08:34 AM

— Me@2013-05-31 10:45:49 PM

2013.05.31 Friday (c) All rights reserved by ACHK

恆心無用 1.5

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Allow no exceptions 2.5 | 活在當下 3.5 | 魚目混珠 5.5 | Presentation 基本原理 1.2.2.3 | Second best 6.2

這段改編自 2010 年 7 月 8 日的對話。

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不是任何人也需要對自己那麼「絕」；但是如果你要奪得最高的 A 級成績，別無他法。

（LMC：其實我是不看「世界盃」的。）

那只是其中一個例子，你可以換上其他，近乎一定會令你分心的事情，例如：

  1. 電視劇大結局；

  2. 男朋友打電話給你，要和你分手；

  3. 家人中了「六合彩」，要你跟他們一同出外慶祝；

等等。

無論這類的事情，對你來說有多重要，你也要忍痛一一拒絕，才能成就大事業。

要做到那麼「絕」，當然是辛苦，但是，你慢慢就會習慣。二來，即使不是講讀書，人生的其他劇情中，有很多時候，「絕」是無可避免的，例如：

假設我有一位心儀的女士。但是，因為某些原因，我已經肯定，她不會是我的未來太太。那樣，無論我多喜歡她；無論她有多麼接近完美，我也不應該追求她。否則，我只會誤人誤己。

換句話說，無論她對我來說有多重要，也不會及我的「未來太太」重要。

— Me@2013.05.29

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The greatest enemy of “the best” is “the second best”.

— Me@2010.11.14

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2013.05.31 Friday (c) All rights reserved by ACHK

UV divergences

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Recall that the UV divergences allow you to divide theories to renormalizable and nonrenormalizable ones – the renormalizable ones only force you to choose a finite number of parameters and cancel their corresponding infinite parts by counterterms.

— Regularization and renormalization

— Lubos Motl

2013.05.29 Wednesday ACHK

Prayer 2.3

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二十八

子曰

吾十有五而志於學
三十而立
四十而不惑
五十而知天命
六十而耳順
七十而從心所欲不踰矩

The Master said, “At fifteen, I had my mind bent on learning.

“At thirty, I stood firm. “At forty, I had no doubts. “At fifty, I knew the decrees of Heaven. “At sixty, my ear was an obedient organ for the reception of truth. “At seventy, I could follow what my heart desired, without transgressing what was right.”

2008.03.06 Thursday CHK_2 2013.05.29 Wednesday ACHK

永恆價值 1.1

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這段改編自 2010 年 4 月 3 日的對話。

（安：我現在的那份工作，內容沒有什麼意義；好像在不斷大規模地，浪費著自己的生命似的。但是，在我現在的心目中，又暫時想像不到，其他有什麼工作是有意義的，而又值得我去追求。）

那樣，兩害取其輕之下，為了保障你的經濟生命安全，你就應該保留現在的那份工作，毋須想太多。

（安：但是，我又過得十分不開心。試想想，每星期有五天是工作天，而每一工作天的大部分時間，我存在於工作的環境之中。再加上我還有幾十年才退休。我十分不希望，我大部分的人生，就那樣荒唐地度過。）

— Me@2013.05.28

2013.05.29 Wednesday (c) All rights reserved by ACHK

Investment, not expense

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What really impresses me most about what Robert’s done is that he’s realized that by selling the outcome that most clients want to hear (higher conversion rates, more leads) instead of what designers tend to emphasize (clean design, HTML5 compliance, etc.) [H]e’s pitching himself as an investment, not an expense.

— bdunn 4 days ago

— Deleted my portfolio, made $30k in my first six months

— Hacker News

2013.05.28 Tuesday ACHK

恆心無用 1.4

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Allow no exceptions 2.4 | 活在當下 3.4 | 魚目混珠 5.4 | Presentation 基本原理 1.2.2.2 | Second best 6.1

這段改編自 2010 年 7 月 8 日的對話。

The enemy of the “best” is the “good”.

我當年學懂這一句以後，處事起來，就變得十分「絕」。

例如，對我來說，本來在溫習時播著音樂，可以提高工作效率。但是，當年，我在思考「應用數學科」的題目時，間中需要高度集中精神。那時，我就立刻關掉那些音樂，無論它多麼悅耳。即使那首歌還在中途，尚未完成；即使那位歌手唱得十分激動，我也會很唐突地中止它。

你也要做到這麼「絕」，例如：

今晚是「世界盃」的決賽，如果不看，我就要等四年後的下一屆。四年後，我已經是大學畢業生了。

不過，那樣不行！

雖然「世界盃」對我來說，是「超級重要」，但不是「第一超級重要」；無論「世界盃」有多重要，也不及今晚我原訂要執行的溫習大計。

不是任何人也需要對自己那麼「絕」；但是如果你要奪得最高的 A 級成績，別無他法。

— Me@2013.05.27

2013.05.28 Tuesday (c) All rights reserved by ACHK

IR divergences

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But the main message is that the IR divergences can never tell you that a physical theory is inconsistent: they just tell you that the IR, long-distance physics may be different than you expected (or than you wanted to see). Production of soft photons in QED and confinement in QCD (and marginally also in conformal theories) are two examples of infrared effects you have to be careful about. But they will never allow you to throw away a theory as an inconsistent one.

— Regularization and renormalization

— Lubos Motl

2013.05.27 Monday ACHK

Prayer 2.2

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Spinoza

Wikipedia:
在倫理學上，斯賓諾莎認為，一個人只要受制於外在的影響，他就是處於奴役狀態，而只要和上帝達成一致，人們就不再受制於這種影響，而能獲得相對的自由，也因此擺脫恐懼。

斯賓諾莎還主張無知是一切罪惡的根源。

Wikipedia:
斯賓諾莎還認為上帝是每件事的「內在因」，上帝通過自然法則來主宰世界，所以物質世界中發生的每一件事都有其必然性；世界上只有上帝是擁有完全自由的，而人雖可以試圖去除外在的束縛，卻永遠無法獲得自由意志。如果我們能夠將事情看作是必然的，那麼我們就愈容易與上帝合為一體。因此，斯賓諾莎提出我們應該「在永恆的相下」（sub specie aeternitatis）看事情。

Russell’s History of Western Philosophy, on Spinoza:
Only ignorance makes us think that we can alter the future;
what will be will be,
and the future is as unalterably fixed as the past.

2007.07.05 CHK2

2013.05.27 Monday (c) All rights reserved by ACHK

恆心無用 1.3

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Allow no exceptions 2.3 | 活在當下 3.3 | 魚目混珠 5.3 | Presentation 基本原理 1.2.2.1

這段改編自 2010 年 7 月 8 日的對話。

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我上次有沒有講過，解決這類問題的那三個字？

（CSY：有呀：「Allow no exceptions.」（不容有例外。））

但是，你所執行的，反而是「always allow exceptions」（總是有例外），當然不能成事。

你初初要迫自己「allow no exceptions」，其實是一件頗難受的事情，因為令你分心的，往往不是「壞事」；真正令你分心的，往往是另一件「好事」。例如，你打算溫習時，發覺當天原來要出外，為朋友慶祝生日。

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記住這句說話：

The enemy of the “best” is the “good”.

.

意思是，如果很明顯是「好事」和「壞事」之爭，你就很明顯會選做「好事」。但是，現實往往是「好事」和「好事」之爭，才會導致你猶豫不決，或者誤入歧途。要全神貫注執行一個任務，你就要在當時斬釘截鐵地，放棄其他「好事」。所以，難受感覺是必須的劇情，無可避免。

有很多做人道理，如果用「愛情」做比喻，就好像立刻變成淺白易明。

如果一位女士「嫁錯郎」，通常也不會是，她原本有一位「好男朋友」和一個「壞男朋友」，而不幸選擇了，嫁給「壞男朋友」。「結錯婚」的通常原因是，有兩位都是非常要好，不相伯仲的可能對象；那才會導致選擇錯誤。

— Me@2013.05.26

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2013.05.27 Monday (c) All rights reserved by ACHK

Hacker-Centric Culture

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But startups can learn an important lesson from the second one. In the software business, you can’t afford not to have a hacker-centric culture.

Probably the most impressive commitment I’ve heard to having a hacker-centric culture came from Mark Zuckerberg, when he spoke at Startup School in 2007. He said that in the early days Facebook made a point of hiring programmers even for jobs that would not ordinarily consist of programming, like HR and marketing.

— What Happened to Yahoo

— August 2010

— Paul Graham

2013.05.26 Sunday ACHK

恆心無用 1.2

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Allow no exceptions 2.2 | 活在當下 3.2 | 魚目混珠 5.2

這段改編自 2010 年 7 月 8 日的對話。

所以，我並不是叫你有恆心，而是要你創作一些特別的方法，令到你自己，無論有沒有恆心，也能妥善完成任務。例如，你們今次因為什麼，而導致沒有依照原訂計劃，閱讀英文書？

（CSY：其實我有看少少。但是，這陣子我剛好有其他要事，剩下來閱讀的時間不多。再加上閱讀時，我的睡意正濃，所以沒有把書看下去。）

我上次有沒有講過，解決這類問題的那三個字？

（CSY：有呀：「Allow no exceptions.」（不容有例外。））

但是，你所執行的，反而是「always allow exceptions」（總是有例外），當然不能成事。

— Me@2013.05.25

2013.05.25 Saturday (c) All rights reserved by ACHK

Renormalization 4

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Renormalizable theories can be extrapolated to high energies

The main feature of renormalizable theories is that their physics may be extrapolated to and remains well-behaved at arbitrary high energy scales – or at least up to energy scales that are exponentially higher – e.g. \exp(1/e^2) times – than the typical scales in your theory. Because of that, any contributions of new particles or, more generally, new physics at these extremely high energy scales Λ are suppressed by 1/Λ^k where k is a positive exponent.

— Regularization and renormalization

— Lubos Motl

2013.05.25 Saturday ACHK

Prayer 2

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In what prayers do men allow themselves! That which they call a holy office is not so much as brave and manly. Prayer looks abroad and asks for some foreign addition to come through some foreign virtue, and loses itself in endless mazes of natural and supernatural, and mediatorial and miraculous. Prayer that craves a particular commodity, — any thing less than all good, — is vicious. Prayer is the contemplation of the facts of life from the highest point of view. It is the soliloquy of a beholding and jubilant soul. It is the spirit of God pronouncing his works good. But prayer as a means to effect a private end is meanness and theft. It supposes dualism and not unity in nature and consciousness. As soon as the man is at one with God, he will not beg. He will then see prayer in all action. The prayer of the farmer kneeling in his field to weed it, the prayer of the rower kneeling with the stroke of his oar, are true prayers heard throughout nature, though for cheap ends.

– Ralph Waldo Emerson

2008.03.12 Wednesday CHK2

恆心無用 1.1

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Allow no exceptions 2.1 | 活在當下 3.1

這段改編自 2010 年 7 月 8 日的對話。

這個星期，你們有沒有什麼，整體的讀書問題？

（CPK：整體的話，應該有英文問題。）

我上次不是叫你們，每星期看一本英文書嗎？你們有沒有做到？

（CSY：看了兩日之後，就沒有再看。）

（LMC：就是這個問題。我們沒有恆心。）

所以，我並不是叫你有恆心，而是要你創作一些特別的方法，令到你自己，無論有沒有恆心，也能妥善完成任務。
　
— Me@2013.05.24

2013.05.24 Friday (c) All rights reserved by ACHK

Customers 2

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Customers Don’t Know What They Want. Stop Expecting Customers to Know What They Want. It’s just never going to happen. Get over it.

– The Iceberg Secret, Revealed

– Joel Spolsky

… ignore what customers ‘say’ and focus on what they ‘do’ with the product.

… it is extremely important to measure and understand how your customers interact with your product. That is the signal. What they say about your product, is mostly just noise.

— Don’t Listen To What Your Customers Say, Look At What They Do

—

2013.05.23 Thursday ACHK