Monthly Archives: March 2011

I am a Strange Loop, 2.1

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自我委員會 2.1

… the “I” as a hallucination hallucinated by a hallucination.

— p. 293, I am a Strange Loop, by Douglas R. Hofstadter

「自我」是一個幻覺。而這個幻覺本身，是由一個幻覺製造出來的。

第一次看這句句子時，我覺得作者是在胡言亂語。現在我才明白作者「胡言亂語」的背後，究竟想帶出什麼意思。

剛才講過，一個人的「自我」，其實是「多重人格」。或者說，「自我」是一個由很多個委員組成的委員會。但是，一般的情況下，我會覺得我是一個單一的人格。那麼，「我是一個單一的人格」這個（錯誤）概念，是誰跟我說的呢？就是由我的「自我委員會」的各個委員跟我說的。即是說，那個「自我委員會」一直在誤導我。

但是，那個被誤導的「我」又是誰呢？

我就是那個委員會。換言之，「自我委員會」一直在誤導「自我委員會」。委員會中的各個人格，一直以為大家是同一個人格。而各個人格，又不斷向其他人格重複強調，大家是同一個人格。

— Me@2011.03.20

2011.03.20 Monday (c) All rights reserved by ACHK

Another source

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Often, when struggling with a book or paper, it’s not you that’s the problem, it’s the author. Finding another source can quickly clear stuff up.

— Michael Nielsen 

2011.03.20 Sunday ACHK

Reality dream

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潛行凶間 4

Life is like a dream. You CREATE your own reality.

— Me@2011.03.18

If you do not create your own reality, you will live in other people’s reality.

— Me@2011.03.19

2011.03.19 Saturday (c) All rights reserved by ACHK

Write 2

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Don’t write the essay readers expect; one learns nothing from what one expects. And don’t write the way they taught you to in school.

— Paul Graham

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2011.03.19 Saturday ACHK

烹飪比賽 2

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這段改篇自 2010 年 4 月 30 日的對話。

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（CKY：很難呀。）

哪一步難呢？我不是要你自己憑空想出這個方法，而是要你看了我的示範後，記得這個方法，從而可以在考試時快速準確地運用出來。

有部分年青人，有一個壞習慣，喜歡企圖「凡事都要自己想出來」。如果不是自己想出來的，就好像沒有那麼有型。千萬不要有這個心態，因為大部分考試時所需的數學技巧，都不會是「原創」，而是靠學習得來的。

如果你在溫習時所抱的心態是「凡事都要自己想出來」的話，那就當然是事事困難。情形就好像你烹飪比賽時要煮菜的話，我會叫你事前要準備好一棵菜。但是，你卻堅持，要在烹飪比賽的時段中，把那棵菜由自己親手種出來，然後投訴：「要在那麼短的時間，種好那棵菜。那真的是很難呀！」

— Me@2011.03.18

2011.03.18 Friday (c) All rights reserved by ACHK

General relativity Model-building

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The core concept of general-relativistic model-building is that of a solution of Einstein’s equations. Given both Einstein’s equations and suitable equations for the properties of matter, such a solution consists of a specific semi-Riemannian manifold (usually defined by giving the metric in specific coordinates), and specific matter fields defined on that manifold.

Matter and geometry must satisfy Einstein’s equations, so in particular, the matter’s energy-momentum tensor must be divergence-free. The matter must, of course, also satisfy whatever additional equations were imposed on its properties. In short, such a solution is a model universe that satisfies the laws of general relativity, and possibly additional laws governing whatever matter might be present.

— Wikipedia on General relativity

2011.03.18 Friday ACHK

向左走 向右走 4

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「一個人有兩個『自我』。左腦為之一個『自我』；右腦為之另一個。」

那只是一個簡化了的講法。實情是，即使只是「左腦」，或者只是「右腦」，也載有超過一個「自我」。

你一直以為你只有一個「自己」，那只是一個幻覺。

— Me@2011.03.17

2011.03.17 Thursday (c) All rights reserved by ACHK

The Stockdale Paradox

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When Collins asked who didn’t make it out of Vietnam, Stockdale replied:

“Oh, that’s easy, the optimists. Oh, they were the ones who said, ‘We’re going to be out by Christmas.’ And Christmas would come, and Christmas would go. Then they’d say, ‘We’re going to be out by Easter.’ And Easter would come, and Easter would go. And then Thanksgiving, and then it would be Christmas again. And they died of a broken heart.”

Stockdale then added:

“This is a very important lesson. You must never confuse faith that you will prevail in the end — which you can never afford to lose — with the discipline to confront the most brutal facts of your current reality, whatever they might be.”

Witnessing this philosophy of duality, Collins went on to describe it as the Stockdale Paradox.

— Wikipedia on James Stockdale

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2011.03.17 Thursday ACHK

機會成本

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這段改篇自 2010 年 4 月 30 日的對話。

（CSK：其實，我真的不知道我的 A.Maths（附加數學）會不會合格。）

不要緊。下星期二才考 A.Maths。你現在還有兩三天。在這兩三天中，你只要狂轟 A.Maths past papers（歷屆試卷）的題目，你合格的機會率就會非常高。

還有，A.Maths 是最後一科，所以，無論你花多少時間來做 A.Maths 練習，機會成本也會非常低。

假如，你考 A.Maths 之前的一天考 Physics（物理），而之後一天考 Maths（一般數學）的話，你溫習 A.Maths 的機會成本就會非常高。花太多時間溫 A.Maths，就會導致不夠時間溫 Physics 和 Maths。即使你的 A.Maths 增加了 10 分，也可能對你沒有意思，因為用同樣的時間溫 Physics 和 Maths 的話，你可能可以賺取 30 分。

但是，你現在卻是「前有去路，後無追兵」。考 A.Maths 之前或者之後，都沒有其他科目要考。所以，無論你花多少時間來做 A.Maths 練習，機會成本也近乎是零。溫習 A.Maths 時，根本沒有其他科目要顧慮。既然那樣，何不放鬆心情，然後盡力而為？

— Me@2011.03.16

2011.03.16 Wednesday (c) All rights reserved by ACHK

Anti de Sitter space

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In mathematics and physics, n-dimensional anti de Sitter space, sometimes written AdSn, is a maximally symmetric Lorentzian manifold with constant negative scalar curvature. It is the Lorentzian analogue of n-dimensional hyperbolic space, just as Minkowski space and de Sitter space are the analogues of Euclidean and elliptical spaces respectively.

It is best known for its role in the AdS/CFT correspondence.

— Wikipedia on Anti de Sitter space

2011.03.16 Wednesday ACHK

History 4

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History seems to me so important that it’s misleading to treat it as a mere field of study. Another way to describe it is all the data we have so far.

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Among other things, studying history gives one confidence that there are good ideas waiting to be discovered right under our noses.

— Paul Graham

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2011.03.15 Tuesday ACHK

向左走 向右走 2.4

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（安：既然一位「分腦病人」的左右兩腦已經不能再直接溝通，為什麼他在大部分情況下，都可以處理到日常事務，而過到正常的生活呢？）

因為雖然「他們」不能直接溝通，但是可以間接溝通。例如，左腦企圖控制右手時，右腦不會事先知道左腦的決定。但是，當左腦做了決定，右手有動作時，右腦會看到，從而立刻知道左腦的意思。

— Me@2011.03.14

2011.03.15 Tuesday (c) All rights reserved by ACHK

70/20/10 Model

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The 70/20/10 Model is also used as a Learning and Development model, according to the Princeton University Learning Process.

    * 70% of learning & development takes place from real-life and on-the-job experiences, tasks, and problem solving.

This is the most important aspect of any learning and development plan. For example, the real learning from a skill acquired in a training program, or from feedback, takes place back on the job when the skill or feedback is applied to a real situation.

    * 20% comes from feedback and from observing and working with role models.

    * 10% of learning and development comes from formal training.
   
   
— Wikipedia on 70/20/10 Model

2011.03.14 Monday ACHK

ANSI Common LISP

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ANSI Common LISP (by Paul Graham) was the book I borrowed for a Machine Intelligence course project in 2000. My memory was that the author was called “Paul something”. I thought that Paul was the one who had invented LISP.

No. It should be John McCarthy.

Later on, during my teaching-in-high-school period, by a Wikipedia biography, I realized that that Paul was not as great as I thought, because he was not the one who had invented LISP.

However, now, I regard him as one of my five most important teachers.

— Me@2010.03.08

— Me@2011.03.14

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2011.03.14 Monday (c) All rights reserved by ACHK