This thesis aims to throw an illuminating light on the as yet neglected concept of nothing in Kant’s system, a concept which is taken into consideration, by Kant, in accordance with the guiding thread of the categories of the understanding. My main argument is that Kant has a fourfold division of nothing and each has a transcendental function in his system. This function is basically a limiting one; setting up negative determinations without which Kant’s system would have never been constituted (...) as it is now. It is shown in the thesis that the concept of nothing is divided basically into four: first, nothing as ens rationis that limits and thereby protects knowledge, secondly nothing as nihil privativum that defines the boundaries of phenomenal reality, thirdly nothing as ens imaginarium that makes possible the unity of experience and finally, nothing as nihil negativum that draws the lines of logical thinking. All make, in the last resort and by being the concepts of the opposite, experience possible. The thesis consists of four chapters. The first chapter is an exposition of all four divisions of nothing, the second is the display specifically of the concepts of ens rationis and nihil negativum, and the third is of the concepts of ens imaginarium and nihil privativum. The auxiliary argument of the thesis is that while Hegel makes a strong charge of externality against and thereby severely criticizes the Kantian concept of the thing-in-itself, - the concept of which I propose to be contained under the concept of ens rationis- Kant has equally convincing arguments against such a charge. This is the topic of the fourth and final chapter which has an implicit aim of creating the image of a powerful critical Hegel but on the other hand an equally enduring and war-like Kant. Kant is presented as a philosopher who has powerful responses to institute a balance between himself and his opponent. When Kant’s differing concepts of nothing are taken into account, Hegel’s attack of externality, it is maintained, appears not to have taken into account the full measure of the resources of the Kantian position. Even when it is said that the attack is against one specific concept of the thing-in-itself alone, Kant still seems to have enough resources for toleration and defence indeed. (shrink)