哲學概論 單元十八 ： 科學是理性知識的典型嗎？(2) 授課教師：王榮麟 【本著作除另有註明外，採取創用CC「姓名標示－非商業性－相同方式分享」台灣 3.0 版授權釋出】 本作品轉載自 Microsoft Office 2003 多媒體藝廊，依據 Microsoft 服務合約及著作權法第 46、52、65 條合理使用

All you can do is pick up one grail and carry it around and see if it keeps on glowing. You are only able to carry one at a time. If the one you are carrying is the Holy Grail, it will never stop glowing. But you would never know if you currently had the Holy Grail, because the grail you are carrying might stop glowing at any moment. All you can do is reject grails that are clearly not holy (since they stop glowing at some point) and keep picking up a new one. You will eventually die (with no afterlife, in this scenario) without knowing whether you succeeded.

Popper 的科學方法論 This is similar to Popper’s picture of science’s search for truth. All we can do is try out one theory after another. A theory that we have failed to falsify up till now might, in fact, be true. But if so, we will never know this or even have reason to increase our confidence.

Popper 的科學方法論 當假設被否證後，科學家應該設法提出大膽 臆測的假設，而不應提出特置的假設（ad hoc hypothesis）。 A modification in a theory, such as the addition of an extra postulate or a change in some existing postulate, that has no testable consequences that were not already testable consequences of the unmodified theory will be called ad hoc modifications.

Popper 的科學方法論 特置假設的例子之一： Having carefully observed the moon through his newly invented telescope, Galileo was able to report that the moon was not a smooth sphere but that its surface abounded in mountains and craters. His Aristotelian adversary had to admit that things did appear that way when he repeated the observations for himself. But the observations threatened a notion fundamental for many Aristotelians, namely, that all celestial bodies are perfect spheres. Galileo’s rival defended his theory in the face of the apparent falsification in a way that was blatantly ad hoc.

Popper 的科學方法論 He suggested that there was an invisible substance on the moon, filling the craters and covering the mountains in such a way that the moon’s shape was perfectly spherical. When Galileo inquired how the presence of the invisible substance might be detected, the reply was that there was no way in which it could be detected. There is no doubt, then, that the modified theory led to no new testable consequences and would be quite unacceptable to a falsificationist.

Popper 的科學方法論 特置假設的例子之二： Prior to Lavoisier, the phlogiston theory was the standard theory of combustion. According to that theory, phlogiston is emitted from substances when they are burnt. This theory was threatened when it was discovered that many substances gain weight after combustion. One way of overcoming the apparent falsification was to suggest that phlogiston has negative weight. If this hypothesis could be tested only by weighing substances before and after combustion, then it was ad hoc. It led to no new tests.

Popper 的科學方法論 科學進展的過程就是理論的大膽臆測與力求 否證的過程。 科學的進展過程是藉著嘗試錯誤 (trial and error)，從錯誤中學習的方式來進行的。每一 次的理論否證，都是科學的一次進展。科學 是在不斷的理論提出、否證、提出、否證… 當中才得以進展，而不斷逼近真理的。

Popper的科學方法論 Popper: “I can therefore gladly admit that falsificationists like myself much prefer an attempt to solve an interesting problem by a bold conjecture, even (and especially) if it soon turns out to be false, to any recital of a sequence of irrelevant truisms. We prefer this because we believe that this is the way in which we can learn from our mistakes; and that in finding that our conjecture was false we shall have learnt much about the truth, and we shall have got nearer to the truth.” (Conjectures and Refutations, p.231.)

問題討論 以 falsifiability 作為科學與非科學之間 的劃界判準是否恰當？ 科學理論一定可被否證，而非科學理論 一定無法被否證嗎？ 可被否證的理論一定是科學理論嗎？不 可被否證的理論一定不是科學理論嗎？

問題討論 Popper 對 falsifiability 一詞的界定足夠 清楚嗎？

問題討論 一旦拒絕承認歸納法的可靠性之後，如何交 代 rational prediction 這一回事？當面對兩個 都尚未被否證的假設 T1 與 T2，其中 T1 已經 通過很多嚴格的測試 (well-corroborated)，都 沒有被否證。T2 是剛被設想出來，尚未予以 測試，從而也尚未被否證的假設。當要用來 預測某現象或是用來建造某個重大工程時， 選擇哪一個理論來做預測會比較合理呢？

問題討論 什麼時候科學會取得重大的進展呢？當 大膽臆測的假設被否證嗎？

Kuhn 與科學革命 T.S. Kuhn (1922-1996) 的名著 The Structure of Scientific Revolutions (first published in 1962) 引發了重大迴響。

Glymour has described Kuhn’s The Structure of Scientific Revolutions as “very likely the single most influential work on the philosophy of science that has been or will be written in the 20th century” It is currently the most widely read. Since its publication in 1962, the University of Chicago Press has sold over one-and-a-half million copies of the English-language edition, and the book had been translated into at least nineteen languages.

What made Kuhn’s book so controversial was its rejection of many of the ways of thinking about science that had become standard during the first half of the twentieth century. Instead of giving logical analyses of individual scientific theories or constructing formal models of concepts such as explanation and confirmation, Kuhn turned to psychology, sociology, and history in order to draw a picture of science that, he claimed, was far more faithful to the original than anything that philosophers of science had yet proposed.

傳統以來對於科學的看法，不管是歸納 論者還是否證論者，不但都無法與科學 史的研究相互印證，反而有所牴觸：科 學運作的方式，科學理論在歷史中的演 變模式都不是傳統哲學所認為的那個樣 子。

Kuhn 嘗試提出一套與科學史的研究更貼近的 看法。

科學的演變模式 前科學 (pre-science)  常態科學 (normal science )  危機 (crisis） 科學革命 (scientific revolution )  新的常態科學 (new normal science )  新的危機 (new crisis ) …..

前科學時期 一門學科在尚未成形之前，往往學派林立， 眾說紛紜，沒有大家共同接受的基本看法。 這是前科學時期的現象。一門學科若永遠停 留在這個階段，則沒有成有成熟科學的機會。 有些學科會逐漸脫離這個階段，研究者會形 成一些共識。他們會發展出一套大家共同接 受的基本觀點與研究方法。

常態科學時期 所謂的常態科學，指的便是在典範 (paradigm) 所提供之架構下所進行的科 學研究活動。 典範指的是如何從事科學研究的一整套 方法、規範：包括了對於世界的看法、 蒐集與分析資料的方法、以及進行科學 思惟和活動的習俗或常規。

常態科學時期 在《結構》一書中，Kuhn 對於典範之意義的界定並 不是很明確，Masterman 甚至分出了 21 種不同的意 思。 但大致說來，有兩種主要的意思：一種即如上述， 另一種比較狹隘的典範意思則指的是極為成功的範 例 (exemplar)。例如，Mendel 對於豌豆的成功實驗 範例；或是 Newton 之相當成功的力學範例； Maxwell 之相當成功的電學範例。這些成功的範例作 為他人之啟發，指出一條如何進行研究的道路，是 指引其他科學家從事科學研究的模範。

常態科學 常態科學的特徵：well organized。 在常態科學時期，科學家通常同意哪些 問題算是重要的，並且對於這些問題應 該如何處理的方式有共識，加上對於怎 樣才算是解決這些問題有共識。 此外，對於世界大致上是什麼樣子也有 一致的看法。

常態科學 有了典範的指導，常態科學時期的科學家們不會浪 費時間精力去爭辯基本原理是否成立。 典範扮演凝聚共識的角色。沒有典範的指導，便沒 有辦法凝聚共識針對重要的問題努力尋求解答。莫 衷一是、無所適從的結果便是各行所是，不會在成 果上有持續的累積與進展。 科學研究工作需要通力合作與共識，所以不能老是 把時間花在質疑基本原理究竟是否成立。典範扮演 的正是凝聚共識的角色。

常態科學 在常態科學期間，科學家從事 puzzle-solving 的工作。 此時的科學家試著使用典範所提供的工具與概念來 描述現象、建造模型、創造新現象。換言之，即嘗 試把現象裝進典範的架構之下，從而精煉典範。 Kuhn 之所以使用 puzzle 而非 problem，乃是由於所 謂的 puzzle 指的是我們雖然尚未解決，但卻是的確 有解的。然而所謂的 problem 卻有可能是無解的。 常態時期的科學家們所做的是典範指出有解，但尚 未被解決，因而有待被解決的 puzzle。

常態科學 典範的作用也在於指出哪些是有待解決的 good puzzles，讓科學家有所適從。 科學家們儘可能在理論上以及在實驗上去擴展典範 的勢力範圍，但卻對於與典範相關的其本原理不採 取批判的態度。 在常態科學時期內的科學家們對於以典範來解決 puzzles 是深具信心的。 當他們無法獲得預期的結果時，他們不會指責典範 出了問題，而是認為自己哪裡出錯了，並且嘗試修 改自己可能犯下的錯誤。 “ Only a poor workman blames his tool. ”

常態科學 所有典範在任何特定的時間都有若干有待解 決、但卻無法解決的異例 (anomaly, a puzzle which resists solution is an anomaly)。 一個典範不會因為有異例無法被解決便被否 決。如果一個典範因為有異例便不足取，那 麼科學事業便會由於動盪不定而根本建立不 起來，也根本不會有什麼樣的科學成就。 例子：Newton 對於月球軌道的計算；Uranus 之軌道的偏離與 Neptune 的發現；Mercury 之軌道的偏離。

版權聲明 頁碼 作品 版權標示 作者／來源 1-29 本作品轉載自 Microsoft Office 2003 多媒體藝廊，依據 Microsoft 服務合約及著作權法第 46、52、65 條合理使用 2 All you can do is pick up one… whether you succeeded. Peter Godfrey-Smith, Theory and Reality: An Introduction to the Philosophy of Science, University of Chicago Press, 2009, p.60-61. 依據著作權法第 46、52、65 條合理使用 3 This is similar to …increase our confidence Peter Godfrey-Smith, Theory and Reality: An Introduction to the Philosophy of Science, University of Chicago Press, 2009, p.61. 依據著作權法第 46、52、65 條合理使用 4 A modification in a theory… ad hoc modifications. Alan Francis Chalmers, What Is This Thing Called Science? University of Queensland Press, 1999, p.75. 依據著作權法第 46、52、65 條合理使用 5 Having carefully observed the…a way that was blatantly ad hoc Alan Francis Chalmers, What Is This Thing Called Science? University of Queensland Press, 1999, p.76.

版權聲明 頁碼 作品 版權標示 作者／來源 6 He suggested that there … unacceptable to a falsificationist Alan Francis Chalmers, What Is This Thing Called Science? University of Queensland Press, 1999, p.76. 依據著作權法第 46、52、65 條合理使用 7 Prior to Lavoisier, … It led to no new tests Alan Francis Chalmers, What Is This Thing Called Science? University of Queensland Press, 1999, p.77. 依據著作權法第 46、52、65 條合理使用 9 I can therefore …and we shall have got nearer to the truth Karl Raimund Popper, Conjectures and refutations: the growth of scientific knowledge, Basic Books, 1962, p.412. 依據著作權法第 46、52、65 條合理使用 15 Glymour has described Kuhn’s ... in the 20th century” Clark Glymour, Theory and Evidence, Princeton University Press, 1980, p.94. 依據著作權法第 46、52、65 條合理使用 16 What made Kuhn’s book so controversial ... had yet proposed. Curd, Martin and J. A. Cover. Philosophy of Science: The Central Issues. 1998, W. W. Norton, p83.依據著作權法第 46、52、65 條合理使用