《道德形而上学基础·第三节·从道德形而上学过渡到纯粹实践理性批判》第10节
Of the Extreme Limits of all Practical Philosophy. All men attribute to themselves freedom of will. Hence come all judgements upon actions as being such as ought to have been done, although they have not been done. However, this freedom is not a conception of experience, nor can it be so, since it still remains, even though experience shows the contrary of what on supposition of freedom are conceived as its necessary consequences. On the other side it is equally necessary that everything that takes place should be fixedly determined according to laws of nature. This necessity of nature is likewise not an empirical conception, just for this reason, that it involves the motion of necessity and consequently of a priori cognition. But this conception of a system of nature is confirmed by experience; and it must even be inevitably presupposed if experience itself is to be possible, that is, a connected knowledge of the objects of sense resting on general laws. Therefore freedom is only an idea of reason, and its objective reality in itself is doubtful; while nature is a concept of the understanding which proves, and must necessarily prove, its reality in examples of experience. There arises from this a dialectic of reason, since the freedom attributed to the will appears to contradict the necessity of nature, and placed between these two ways reason for speculative purposes finds the road of physical necessity much more beaten and more appropriate than that of freedom; yet for practical purposes the narrow footpath of freedom is the only one on which it is possible to make use of reason in our conduct; hence it is just as impossible for the subtlest philosophy as for the commonest reason of men to argue away freedom. Philosophy must then assume that no real contradiction will be found between freedom and physical necessity of the same human actions, for it cannot give up the conception of nature any more than that of freedom. Nevertheless, even though we should never be able to comprehend how freedom is possible, we must at least remove this apparent contradiction in a convincing manner. For if the thought of freedom contradicts either itself or nature, which is equally necessary, it must in competition with physical necessity be entirely given up.
注释摘要
这段文字标志着康德论证中的一个关键转折。此前他已将道德的最高原则追溯到了自由的理念，但自由本身却陷入了一个棘手的困境：一方面，我们每个人都必然在实践上将自己视为自由的，否则一切“应该”都无从谈起；另一方面，我们对世界的全部理论知识都建立在自然必然性之上，即每一件事都有其先行原因，这是经验之所以可能的条件。康德在此要做的，不是解决这个困境，而是精确地划定它的…