康德論矛盾律

Kant on the Law of Contradiction

康德將矛盾律當作一切判斷的消極條件(negative Bedingung)，也作為一切真理的普遍且消極的判準；也就是說，無論是分析判斷或綜合判斷，其主賓詞之間的關係均不能自相矛盾。在批判期之前，康德已經注意到了矛盾律擁有不同的表達形式，此時，他仍然持著德國經院派哲學(Schulphilosophie)家們對於矛盾律的理解。在《純粹理性批判》裡，康德提到一個著名的矛盾律的表達方式，這個形式即：「這是不可能的：某某同時既是又不是。」(es ist unmoglich, daβ etwas zugleich sei und nicht sei)。他認為這個形式雖然抽離了所有的內容，而且僅僅是一種形式原則，但是它卻包含了一個綜合(synthesis)。他認為這個語句透過時間而為吾人所感受，矛盾律僅僅作為一個純然論理的原則(ein bloβ logischer Grundsatz)，其所論述出來的內容根本不受時間條件的限制，也就是同時性根本是多餘的。在矛盾律的運用上，我們根本上不需要加上任何時間條件的限制。本文將研究康德前後期對於矛盾律的看法如何轉變？以及他為何且如何要取消「同時性」。本文從柏拉圖和亞理斯多德對於矛盾律的見解出發，分析他們何以必須設定「同時性」作為矛盾律的先決條件。然後分析康德的批判前期和批判期對於矛盾律的看法之差異。通過本文的分析，可以知道：在柏拉圖、亞理斯多德談矛盾問題，以矛盾律作為知識原則時，「同時」是規範這個原則的重要指標，不論是從 存有、存有學或者論理上來講，「同時」是保障矛盾律得以成為原則的必要條件；對康德則不然，在康德哲學的發展裡，康德在批判前期雖然已經用同一律和概念分析作為談論問題的焦點，但是整個目的是為著形上學的對象如何得以合法地被證明，在批判期的轉向裡，康德不再接受傳統的矛盾律形式，從而他抛棄了「同時」的假定，因為他只承認判斷的概念分析而不再以經驗對象作為主詞。

The law of contradiction, as Kant believes, can be confirmed as the negative condition for all judgments, i.e. the general and negative criterium of all the truths. It's to say that the relation between the subject and the predicate can not be contradictory in both synthetical and analytical judgments. In the pre-critic period, Kant had already paid attention to the variant formulae of the law of contradiction in his Latin dissertation named as 'Principorum primorum cognitionis metaphysicae nova dilucidatio'. But he had still believed that the law of contradiction can be used as a metaphysical principle as the 'German Shulphilosophen' had done. In the Critique of pure reason, he relates the laws of contradiction to a famous formula as following: 'es ist unmoglich, daβ etwas zugleich sei und nicht sei / it's impossible that something is and is not in the meanwhile.' He thinks that all the empirical contains are abstracted in this formula which can be used as a formal principle of knowledge, but it implies an empirical synthesis, although it can be analytical. He claims that the law of contradiction can be applied as a purely logical principle which need not be restricted by the condition of the simultaneity, because the simultaneity seems superfluous. In this paper, I aim at investigating the reason why Kant changes his opinions about the law of contradiction between the pre-critic and the critic period and finally negates the condition of simultaneity from the law of the contradiction. By the first step, I analyze Plato's and Aristotle's thinking of the law of contradiction in order that I can ascertain the reason why the simultaneity must be the necessary condition for the law of contradiction. Secondly, I study the different formulae of the law of contradiction in Kant's Latin dissertation 'Principorum primorum cognitionis metaphysicae nova dilucidatio' and find that he did take the laws of Identity as the primary condition, but he still kept the simultaneity as the formal condition for the law of condition. In his critic period, he finally began to distinguish the analytical judgment from the synthetical and the synthetical judgment a priori from the synthetical a posteriori, and tried to rectify his analysis of the judgment with a conceptual definition of the subject which can not be individual-- this is the reason why he got rid of the simultaneity as the formal condition for the law of contradiction.