20130123

「念力」的科學解釋?

《主場新聞》剛轉載了周兆祥的舊文〈「念力」的科學解釋〉,這是一篇語無倫次的壞文章,實在不值得轉載。

首先,文章完全沒有解釋甚麼是念力,更遑論提出科學的解釋,文不對題至此,也算罕見了。周兆祥在「念力」一詞後括了「mind power 指內心的力量」,似乎就當是解釋了「念力」的意思,但這只是用一個不清楚的詞語(「內心的力量」)去代替另一個不清楚的詞語(「念力」),根本不是解釋 ---「內心」指甚麼?信念?情感?欲望?思考過程?非物質的心靈?還是包括以上一切?

內心的力量應該是一種 power了(周兆祥說那是 mind power),但在這個「解釋」提出之前的一段,周兆祥講的是能量(energy)和質量的互轉,並說「明白了這個道理」,念力「就沒有甚麼神秘了」,可是,energy power 是兩個不同(但相關)的概念,究竟念力是一種 energy 還是 power ?總之,假如你搞不清楚甚麼是念力,說「念力」指內心的力量,兼扯上「能量」這一概念,只會令你更加糊塗。

事實上,周兆祥在談能量和質量互轉的那一段,已暴露了他對科學的無知。他說「E=MC2就是能量,就是物質的重量大小,就是速度」,短短四句,就有兩個錯誤:不「就是速度」,而是光速; M 是質量(mass),但在物理學裏「質量」並不是指物質的重量大小,質量和重量的分別,真是歌仔也有得唱:


周兆祥反對的科學主義(scientism)的確應該反對,然而,反對科學主義的人如果對科學太無知,便很容易變成對科學有偏見,甚至導人迷信,此不可不察也。

(這篇文章還有不少其他問題,但已有人論過,不贅了。)

30 則留言:

  1. 如果物質的確可以就咁轉變為能量,就唔洗起咁多核電廠,叫幾個深綠份子用念力發電就得啦。

    如果凡事用「念力」就可以解決,就唔會有咁多人要用偉哥。

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    1. 質量的確可以轉換為能量,核電是現時最有效的轉換方法;其實燒一枝火柴也是質量轉換為能量,不過只能轉換火柴中極少的物質為能量。

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    2. //燒一枝火柴也是質量轉換為能量// It depends on how one sees it or what (kind of) mass one is talking about. (For example, some people may say that an hot object has more mass than when it is colder.) But I think when scientists talk about 質量轉換為能量 they don't think about 燒一枝火柴, and when they talk about 燒一枝火柴, they will think about chemical energy converting to heat and light. --zpdrmn

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    3. I have read the match burning description 3 times and the log burning description 2 times or more before. The former has been on the web for at least 6 years. Without getting into materials that are too technical, please refer to the 2 short paragraphs in wiki:
      the first two paragraphs of the section Binding Energy And The "Mass Defect" up to the clause "so that total mass is conserved."

      http://en.wikipedia.org/wiki/Mass%E2%80%93energy_equivalence

      Note 1: note the difference indicated there: matter converted to energy vs "mass" converted to energy.
      Note 2: For the dynamite case: when the surrounding absorbs the heat, its mass increases. Some loses some gains. The total?

      Again, as I said, it depends on how one sees it. So, whatever opinion one has, that's fine.
      Also, I would guess that there aren't experiments measuring the mass difference between the before and after masses in the match and log burning cases. But people discuss these cases as if there are experiments done. (Well, they don't say "in theory.") Even if there are experiments confirming the claim (I wouldn't be surprised if the results support it), we still have to consider the 2 paragraphs I refer to. --zpdrmn

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    4. If you are interested, you can take a look at Ch.12 of Richard Wolfson's Simply Einstein: Relativity Demystified and Ch.6 of Brian Cox's & Jeff Forshaw's Why Does E=MC2.

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    5. I don't have these books. I may be able to get access to the first later. But in the meantime, let me explain what bug me in those descriptions of match and log burning. You can tell me if the authors of books you suggest would describe them the same way. If they do, I'll give up and just say it may be a disservice to the readers when they have such a platform to explain things in details.
      There are the two points that bug me. (Well, 3 points. I'll talk about 2 only.)
      1. Let me talk a bit about the concept of rest mass M0. I don't really like it but I have no say in it, so I have to take it. I don't like it because I may need to do bookkeeping, depending on what problem is at hand. The rest mass includes mechanical (or gravitational) potential energy, chemical (chemical potential) energy, heat energy, and whatnot. Too many things. Bookkeeping. I don't know much about the history how it happened. It may be that from Einstein's equation if one excludes all the other terms on the RHS except the first, one is left with E0=M0*c*c. That's elegant and convenient in writing it out. (The second term of the RHS of the equation is kinetic energy, it may be the reason that when it and the higher terms are excluded, the M in the first and the only remaining term, M0, is called the rest mass. Again, I don't know the history.) Now, let's look at the match and log burning cases, they don't talk about what's in the rest mass. What part of the rest mass is converted into energy? They don't say. The chemical energy part of the rest mass is converted into heat and light energy. If I have only a few lines to explain things, I would skip this rest mass thing and simply use the good old energy conversion, one form of energy converts into some other forms of energy. (That's what I did earlier, hoping that I didn't need to write too much.)

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    6. 2. Where do the heat and light energy go? They don't say either. Such lack of explanation (may be from other cases than the 2 we are discussing here) gets hammered by the writer of the 2 paragraphs I refer to. He/she even calls it false use of mass-energy conversion. I am not sure what the writers of the burning cases know or don't know. So, I won't say that it is false use. The point is that we should look at the whole thing as in closed systems if we can. These cases, unlike nuclear reactions, do not involve a huge amount energy so that we may not be able to contain it. (When we can measure mass to very high accuracy, ten to minus whatever exponent in grams, and can do experiments on this burning mass into energy, we'd better use closed systems.) Why do they look at them as in open systems? That bugs me. In a closed system as described in the 2 paragraphs, we can keep account of where the heat and light go. They get absorbed by the surroundings and thus the rest mass of the surroundings is increased. (We should do some bookkeeping here too. What parts of the rest mass of the surroundings are increased?) In such sense the rest mass of the closed system remains the same. (some gain some lose.) Even before this mass-energy conversion thing, when scientists looked at mass conservation they considered closed systems. Same for energy conservation.
      What bug me: 1. No bookkeeping of the rest mass, thus the chemical energy. (They don't even mention this term or the like: chemical energy, chemical potential energy, binding energy etc. I haven't checked the exact definition of binding energy, it may include something more than chemical energy.)
      2. Not giving a description of the bigger picture, namely, a closed system. Well, there is one more thing that bugs me, but I don't want to write anymore. It is briefly discussed but not explained in details in the 2 paragraphs I refer to.

      Why they bug me? They may mislead readers.
      For example, when a reader thinks about in the match or log burning case the mass (should be the chemical energy part of the rest mass) that converts into energy, he/she may think about the “wrong” part of the rest mass, or they may not even know there are different parts.
      The “wrong” part may be the “matter” that the writer of the 2 paragraphs talks about. But I am not sure, too many people, the writers, the readers... are involved. How could I know what they think? --zpdrmn

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    7. //You can tell me if the authors of books you suggest would describe them the same way. If they do, I'll give up and just say it may be a disservice to the readers when they have such a platform to explain things in details.//

      - Yes, they do. Both authors (and they are physicists) say E=MC2 applies to match and log burning. As Cox & Forshaw say, "The conversion of mass to energy is therefore not such an exotic process. It is happening all the time." (Why Does E=MC2?, p.145).

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  2. 念得死D暴君夠好喇!

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    1. 就用科學念死D暴君,但用什麼科學呀!
      who would tell?

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    2. 想起當年聲稱能千里發功的氣功師嚴新。

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  3. “主場新聞”這網站概念是好的,但文章水準參差不齊是一個很大的問題。
    我想可能是文章覆蓋的題目太多,編輯的知識不足以挑選適合的文章吧!

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  4. 十年前聽其周兆祥,覺得他很前衛,之後讀過他有關疫苗有害的文章(http://www.simonchau.hk/Chinese_B5/),深覺要遠離此人的言論。

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    1. 他說的完全沒有數據支持,真嚇人。

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  5. 無讀周兆祥的理論文章, 有聽他在香港電台的節目. 有點宗教綠感覺.雖然對他有關椰子油效用懷疑, 但他關於吃和人與昆蟲相處的經驗的確值得参考.我對食物的選擇範圍大了.
    早就覺得他們有些宗教熱. haode2010

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  6. 他的club o 一直宣揚銅人療法, 敲公仔醫病.

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    1. 銅人療法我還是第一次聽到,真是孤陋寡聞了。看了一個網頁的描述,很神奇啊:銅人療法

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  7. 王SIR放了連結的歌仔好有趣。原來此人將很多科學原理寫成歌,適合初中甚至高中的理科生看。

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  8. 周兆祥說的//...而能量(光、熱、思想)其實是質量放射出來的外化現象。//
    不知他如何去證明「思想」也是一種能量?

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  9. 「念力」是假的,只是人的幻想。下面網頁裡的右上角的那幅照片
    “拍攝於1912年,當中的伊娃卡里耶爾雙手之間出現了閃光。”
    可以明顯看到閃光是加上去的,請看看那人的小腹和大腿部份,那麼強的閃光理應令到小腹和大腿上也很光亮才是,但照片中大腿和小腹部份的亮度竟然與小腿前面的亮度基本一樣,是手法低劣的明顯的造假。
    http://zh.wikipedia.org/zh-hk/%E5%BF%B5%E5%8A%9B

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  10. 講起念力﹐我倒想問問人類將念頭化作行動這個行為﹐本身有甚麼科學解釋﹖
    其次﹐我倒想知道你有否聽過甚麼成功案例﹐能使一個抑鬱症病患﹐單靠服用抗抑鬱藥而痊癒﹖甚至抑鬱症﹑精神病本身﹐查實有甚麼科學解釋﹖

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    1. //講起念力﹐我倒想問問人類將念頭化作行動這個行為﹐本身有甚麼科學解釋﹖//

      - 咁深我點識答呀!

      //其次﹐我倒想知道你有否聽過甚麼成功案例﹐能使一個抑鬱症病患﹐單靠服用抗抑鬱藥而痊癒﹖甚至抑鬱症﹑精神病本身﹐查實有甚麼科學解釋﹖//

      - 抗抑鬱藥的效用是很成疑問的,這本書有詳細資料:The Emperor's New Drugs: Exploding the Antidepressant Myth

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  11. 周兆祥的排膽石營是假

    http://www.discuss.com.hk/viewthread.php?tid=21705610&page=1&pid=357353990

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    1. 謝謝。這件事值得寫一篇文章公告於世。

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  12. 真的不太知道weight and mass分別,歌裡說mass用kg and g,weight用n,咁我地平時講既體重(weight)用kg,到底系指地球只用50kg就可以令我呢個人唔浮起黎,定我mass有50?

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