物自体 (康德)

物自体，或自在之物（德语：Ding an sich；英语：Thing in itself）是康德所介绍的概念。物自体是独立于观察的客体。这个概念在哲学家中间产生了很多争论。^[1]

康德

康德认为所有客体的总和，也就是这个经验的世界，它的存在是经先天认知形式（决定其以表象（representation）方式呈现）连结至认知主体。康德对物自体的介绍如下:

And we indeed, rightly considering objects of sense as mere appearances, confess thereby that they are based upon a thing in itself, though we know not this thing as it is in itself, but only know its appearances, viz., the way in which our senses are affected by this unknown something.^[2]

（事实上，既然我们有理由把感官对象仅仅看做是现象，那么我们就也由之而承认了作为这些现象的基础的自在之物，虽然我们不知道自在之物是怎么一回事而只是知道它的现象，也就是只知道我们的感官被这个不知道的什么东西感染的方式。^[3]）

雅各比

第一个对物自体概念提出批判的是弗里德里希·海因里希·雅各比，他这样认为：

I could not enter into the system without the assumption of the concept of the thing-in-itself and, on the other hand, I could not remain in it with this concept.^[4]

（在没有对物自体概念的假设之下，我无法进入这个体系；另一方面，我也无法和这个概念一起待在这个体系里。）

Gottlob Ernst Schulze

匿名出版的《埃奈西德穆》（英语：Aenesidemus (book)）成功给了康德以致命的一击，根据康德的说法，物自体无法导致现象，因为因果律的范畴只能运用在经验的客体上。因此康德也无法宣称物自体的存在。此书后来表明正是G. E. Schulze（英语：Gottlob Ernst Schulze）所著。

这个矛盾后来也被接受为是物自体这个概念存在的主要问题。这本书与此书对物自体的一击对费希特产生了巨大影响。叔本华称G. E. Schulze为康德所有对手中最犀利的一位。^[5]

约翰·戈特利布·费希特

起初，费希特很赞同康德哲学，包括物自体的概念，但是Schulze的书改变了他的观点。

Aenesidemus, which I consider one of the most remarkable products of our decade, has convinced me of something which I admittedly already suspected: that even after the labors of Kant and Reinhold, philosophy is still not a science. Aenesidemus has shaken my own system to its very foundations, and, since one cannot live very well under the open sky, I have been forced to construct a new system. I am convinced that philosophy can become a science only if it is generated from one single principle, but that it must then become just as self-evident as geometry.^[6]

（《埃奈西德穆》，我认为它是我们这个时代最为杰出的作品，它加深了我的怀疑：即便是经过康德和莱茵霍尔德的努力，哲学依旧不是一门科学。《埃奈西德穆》动摇了我的体系中最基础的部分并使它分崩离析。因为没有人能在毫无遮蔽的天空下活得很好，所以我被迫建立一个新的体系。我相信哲学能成为一门科学，只要它能从一个简单的原则开始，那么这个原则就必须跟几何学一样自明了。）

叔本华

尽管叔本华赞同对康德物自体概念的批判，认为康德引入物自体的方式是不可接受的，但是叔本华还是赞同康德对物自体存在的宣称，并认为康德区分物自体和现象是他最伟大的功绩。^[5]

Philipp Mainländer

Mainländer（英语：Philipp Mainländer）的观点较为特别，他称颂康德打破了他自己原来的哲学规则，Mainländer也认为物自体是存在的。

He did it, because he feared nothing more than the allegation, that his philosophy is pure idealism, which makes the whole objective world into illusion and takes away all reality from it. The three remarks of the first part of the Prolegomena are, with this in mind, very much worth reading. I cannot condemn this great inconsequence. It was the smaller one of two evils, and Kant bravely embraced it.^[7]

（他这么做，是因为他毫无畏惧，唯独惧怕认为他的哲学是纯粹唯心论的指控，这个指控会使整个客观世界陷入错觉之中，并把它的真实性完全剥离。带着这样的想法，《未来形而上学导论》第一部分的三篇注释就变得十分值得拜读了。我无法指责这伟大的逻辑上的不连贯。二者皆害，此害较轻，康德勇敢地接受了它。）

引用

^ Thielke, Peter; Melamed, Yitzhak. Salomon Maimon. Zalta, Edward N. (编). The Stanford Encyclopedia of Philosophy Fall 2015. Metaphysics Research Lab, Stanford University “Perhaps the most obvious problem — and certainly one of the earliest — that Kant faces concerns the issue of the thing in itself.”. 2015 [2018-02-10]. （原始内容存档于2020-06-04）.
^ Kant Immanuel. Prolegomena to Any Future Metaphysics. : § 52c.
^ 伊曼努尔·康德, 庞景仁译. 任何一种能够作为科学出现的未来形而上学导论. 商务印书馆. 1997-4: 86. ISBN 9787100017985. 请检查|date=中的日期值 (帮助)
^ S. Atlas. From Critical to Speculative Idealism. : p. 21.
^ ^5.0 ^5.1 Arthur Schopenhauer. The World as Will and Representation.. Kant’s greatest merit is the distinction of the phenomenon from the thing in itself … This defect, as is known, is the introduction of the thing in itself in the way chosen by him, the inadmissibleness of which was exposed at length by G. E. Schulze in "Aenesidemus " and was soon recognised as the untenable point of his system. … It is most remarkable that one of Kant’s opponents, and indeed the acutest of them, G. E. Schulze …. : Vol. 1 Criticism of the Kantian Philosophy.
^ Fichte. Early Philosophical Writings. Cornell University Press. 1993: p 4.
^ Philipp Mainländer. Die Philosophie der Erlösung. "Er that es, weil er Nichts mehr fürchtete als den Vorwurf, seine Philosophie sei der reine Idealismus, welcher die ganze objektive Welt zu Schein macht und ihr jede Realität nimmt. Die drei Anmerkungen zum ersten Buche der Prolegomena sind, in dieser Hinsicht, sehr lesenswerth. Diese große Inconsequenz kann ich nicht verdammen. Sie war das kleinere von zwei Uebeln, und Kant ergriff es herzhaft.". : p. 438.

[1] Thielke, Peter; Melamed, Yitzhak. Salomon Maimon. Zalta, Edward N. (编). The Stanford Encyclopedia of Philosophy Fall 2015. Metaphysics Research Lab, Stanford University “Perhaps the most obvious problem — and certainly one of the earliest — that Kant faces concerns the issue of the thing in itself.”. 2015 [2018-02-10]. （原始内容存档于2020-06-04）.

[2] Kant Immanuel. Prolegomena to Any Future Metaphysics. : § 52c.

[3] 伊曼努尔·康德, 庞景仁译. 任何一种能够作为科学出现的未来形而上学导论. 商务印书馆. 1997-4: 86. ISBN 9787100017985. 请检查|date=中的日期值 (帮助)

[4] S. Atlas. From Critical to Speculative Idealism. : p. 21.

[:0-5] 5.0 ^5.1 Arthur Schopenhauer. The World as Will and Representation.. Kant’s greatest merit is the distinction of the phenomenon from the thing in itself … This defect, as is known, is the introduction of the thing in itself in the way chosen by him, the inadmissibleness of which was exposed at length by G. E. Schulze in "Aenesidemus " and was soon recognised as the untenable point of his system. … It is most remarkable that one of Kant’s opponents, and indeed the acutest of them, G. E. Schulze …. : Vol. 1 Criticism of the Kantian Philosophy.

[6] Fichte. Early Philosophical Writings. Cornell University Press. 1993: p 4.

[7] Philipp Mainländer. Die Philosophie der Erlösung. "Er that es, weil er Nichts mehr fürchtete als den Vorwurf, seine Philosophie sei der reine Idealismus, welcher die ganze objektive Welt zu Schein macht und ihr jede Realität nimmt. Die drei Anmerkungen zum ersten Buche der Prolegomena sind, in dieser Hinsicht, sehr lesenswerth. Diese große Inconsequenz kann ich nicht verdammen. Sie war das kleinere von zwei Uebeln, und Kant ergriff es herzhaft.". : p. 438.

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