自一七八一年《純粹理性批判》出版以來，物自身的概念就一直飽受爭議，因為在康德的系統之下，因果關係只對現象有效，不能超出經驗而使用，所以若預設一個作為原因而存在於現象或經驗之外的對象自身，以引起我們心中的各種表象的話，那麼這樣的說法就會是不一致的，然而，康德似乎又主張這樣的刺激是心靈進行認識活動的起點，因此雅各比(F. H. Jacobi)對此作了一個著名的評論：「若沒有這個預設，我將無法進入這個系統；然而一旦有了它，我卻無法停留於其中」(Werke, vol. 2, p.304)。這個問題一直延續到了當代，並分成兩種不同的立場，一是以史卓森為首的形上學式詮釋，二是以艾利森為代表的方法論式詮釋。然而，筆者將指出這兩種詮釋都不正確，它們都僅是片面地把握康德物自身的意義，因而仍有許多詮釋上的困難。

筆者將在本文中提出有別於上述兩種詮釋的第三種說法，並按照《純粹理性批判》的不同脈絡為先驗觀念論(transzendentaler Idealismus)與物自身區分出各種不同的意義。本文將按照《純粹理性批判》最初的提問開始，順著康德的哥白尼式轉向、時間空間的學說、範疇與圖式的理論，一直到先驗理念與二律背反，在這個過程中逐步說明先驗觀念論與物自身在不同脈絡中的意義。筆者認為，對於康德來說，先驗觀念論、現象和物自身這些概念並不是只具有一個特定意義的特殊術語。康德並非創造這些語詞，僅僅是藉著這些常見的用語去表達他想說的不同意義。最後，筆者將主張，我們應該區分廣義與狹義的先驗觀念論，而物自身的概念按照脈絡將至少具有五種不同的意義。

Since Critique of the Pure Reason was published in 1871, the concept of thing in itself has been always a controversial issue. Because in Kant’s System, causal relation is valid only for appearances and can not be applied outside the experiences, so it is a conflict to assume an object in itself as a cause that exists outside the appearances or experiences and results various representations in our minds. However, Kant seems to claim that this affection is the outset of cognizing activities of the mind. Jacobi once criticized the presumption of thing in itself: without the presupposition I could not enter into the system, but with it I could not stay within it. This problem still exists nowadays, and the interpretations are separated into two ways: metaphysical and methodological. However, I will argue that the two interpretations are both incorrect. They only grasp the meaning of thing in itself partially and thus can not interpret it without difficulties.

In the essay, I will give another interpretation which is different from the two mentioned, and then differentiate various meanings of thing in itself and transcendental idealism according to different contexts in Critique. I will explain the meanings of thing in itself and transcendental idealism in Kant’s critical inquiry, in his Copernican turn, in the doctrine of time and space, in his theory of categories and schemata, and in transcendental ideas and antinomies. The concepts of thing in itself in these contexts are all distinctive. For Kant, transcendental idealism, thing in itself or appearances are not terms that have only one certain and peculiar meaning. Kant does not create these terms, which have their ordinary meanings, but only convey by them what he wants to say in different contexts. In the end of the essay, I will conclude that transcendental idealism should be considered in two senses, and the concept of thing in itself has five distinctive meanings in different contexts.

中文參考書目
康德 (Immanuel Kant)，《純粹理性批判》，鄧曉芒譯，台北：聯經，2004。
───，《實踐理性批判》，鄧曉芒譯，台北：聯經，2005。
───，《判斷力批判》，鄧曉芒譯，台北：聯經，2004。
───，《一切能作為學問而出現的未來形上學之序論》，李明輝譯，台北：聯經，2008。
───，《康德著作全集 第一卷：前批判時期著作I(1747-1756)》，李秋零譯，北京：人民大學，2010。
───，《康德著作全集 第二卷：前批判時期著作II(1757-1777)》，李秋零譯，北京：人民大學，2007。
───，《康德著作全集 第九卷：邏輯學、自然地理學、教育學》，李秋零譯，北京：人民大學，2010。
海德格 (Martin Heidegger)，《物的追問》，趙衛國譯，上海：譯文，2008。
韓水法，《康德物自身學說研究》，台北：台灣商務印書館，1990。

英文參考書目
Allison, Henry E, Kant's Transcendental Idealism : An Interpretation and Defense, New Haven, Conn.: Yale University press, c2004, Rev. and enl.ed.
───, “Transcendental Realism, Empirical Realism and Transcendental Idealism” in Kantian Rewiew, V.11 (2006)
Cassirer, Ernst, Kant’s Life and Thought, translated by James Haden, Lodon: Yale University press, 1981.
───, Substance and Function, translated by William Curtis Swabey, New York: Dover Publications Inc. press,1980.
Caygill, Howard, A Kant Dictionary, Wiley-Blackwell press, 1995.
Cleve, James Van, Problems from Kant, Oxford [England] ; New York: Oxford University press, 1999.
Decartes, René, The Philosophical Writings of Descartes, 2 vols, translated by J. Cottingham, R. Stoothoff and D.Murdoch, New York: Cambridge University press, 1985.
Gardner, Sebastian, Routledge Philsophy GuideBook to Kant and the Critique of Pure Reason. London: Routledge press, 1999.
Guyer, Paul, Kant and the Claims of Knowledge, New York: Cambridge University press, 1987.
Hume, David, A Treatise of Human Nature: Volume 1: Texts, ed. by David Fate Norton, OUP Oxford press, 2011.
Jacobi, Friedrich Heinrich, On Transcendental Idealism. in Kant’s Early Critics: The Empiricist Critique of the Theoretical Philosophy, ed. and trans. Brigitte Sassen. New York: Cambridge University press, 2000.
Kant, Immanuel, Critique of Pure Reason, translated & ed. by Paul Guyer and Allen W. Wood, Cambridge: Cambridge University press, 1998.
Langton, Rae, Kantian Humility: Our Ignorance of Things in Themselves, Oxford [England] : Clarendon press ; New York : Oxford University press, 1998.
Longuenesse, Béatrice, Kant and the Capacity to Judge, trans. By Charles T. Wolfe, New Jersey: Princeton University press, 2001.
Strawson, Peter F., The Bounds of Sense- An Essay on Kant’s Kant's Critique of Pure Reason, London : Methuen, 1966

德文參考書目
Kant, Immanuel, Immanuel Kants gesammelte Schriften, herausgegeben von der Deutschen (Königlichen Preussischen) Akademie der Wissenschaften, 29 vol. Berlin: Walter deGruyter, 1902.
───, Kritik der reinen Vernunft. herausgegeben von Jens Timmermann, Hamburg: Felix Meiner Verlag, 1998.
Cohen, Hermman, Kants Theorie der Erfahrung, Berlin: Ferd. Dümmlers Verlagbuchhandlung, 1885.
Koch, F. Anton, Kant, Kritik der reinen Vernunft, Vorlesungsskript im Wintersemester 2009/10 (unveröffentlicht).