論康德的「物自身」概念

Abstract

康德曾以「我得揚棄知識以便給信念保留地盤」來概述其寫作《純粹理性批判》的動機。本文將以此為線索來處理長久以來困擾著康德學者的概念——物自身——所引起的問題，諸如物自身刺激感性以作為現象的成因，物自身不具時空性等等。目前學界在詮釋物自身問題有兩種相互競爭的學說。較傳統的「兩種對象說」視現象與物自身為兩個獨自存在的對象，然而通常即是此說造成上述的問題。新近的「兩種概念說」則視現象與物自身為對同一個對象的兩種不同的設想方式，通常此說較能融貫地解釋物自身的問題。本文將透過批評目前英語學界倡導兩種概念說最重要的學者Henry E. Allison的看法，來說明兩種學說都誤解了康德是如何談論物自身。兩種對象說誤把這些談論當成是我們對物自身的認識，導致了康德批判哲學的不一致；兩種概念說則把正確解決上述問題的關鍵誤導成物自身與現象是否同一的問題上。 解決問題的關鍵在於康德認為人類認識是推論性的，亦即我們的認識是兩種相異——接受性與自發性——的認識機能相互合作之後的成果。物自身這個概念，由於自發性而為可能，由於接受性而為必要。我們談論到物自身的性質，只是我們設想它們為如此，而並非是我們認識到它們如此。而康德之所以要設想物自身為不具有時空性，實際上正好就是為了揚棄知識以求保衛信念。

“I had to deny knowledge in order to make room for faith,” Kant thus stated his mainspring of the composition of the Critique of Pure Reason. This thesis will take it as the guiding light to dissolve the problems resulting from the long-perplexing notion of things in themselves, such as that sensibility is affected by things in themselves in order that their appearances are given to us and the nonspatiotemporality of things in themselves. Now there are two competitive positions on these problems: the two-object view construes things in themselves and appearances as two distinct objects, a view which usually generates these problems; the two-conception view construes them as two different considerations of the same object, a view which is generally able to give a coherent account. I will explicate that, through criticizing the proposal of Henry E. Allison, who is one of the prominent scholars of the two-conception view, both views misunderstand how Kant talks of things in themselves. The two-object view regards these talks as genuine cognition, which cannot be consistent with Kant’s critical doctrine, and the two-conception view misleads the very answer to these problems into the identity between appearances and things in themselves. The very answer lies in Kant’s insight that human cognition is discursive, that is, our cognition is the result of the cooperation of two heterogeneous, receptive and spontaneous, faculties. The spontaneity makes possible and the receptivity makes necessary the notion of things in themselves. Our talks of things in themselves, however, are merely conceptions but not cognition. One of Kant’s conceptions of things in themselves, their nonspatiotemporality, is actually how Kant denies knowledge to save room for faith.