Abstract

The dissertation analyzes Kant's arguments against Cartesian skepticism from the precritical period up to the "Reflexionen zum Idealismus" . It is argued that in the silent decade , the skeptical challenge leads Kant to reinterpret the foundation of his philosophy, namely, the distinction between appearances and things in themselves. Realizing the impossibility of refuting the skeptic through the identification of appearances with mental entities and the affirmation of the mind-independent existence of things in themselves as causes of the appearances , Kant is forced to modify radically his notion of appearances in such a way as to make a new anti-skeptical argument possible. Thus, he no longer interprets appearances as mental entities, but as genuine, mind-independent objects. In this way, the skeptical challenge leads Kant to his mature notion of empirical realism, as presented in the 1781 Fourth Paralogism. ;The dissertation also shows that the mainstream evaluation of the arguments from the critical period needs to be revised. Some interpreters consider Kant's overall attempt to refute the skeptic ultimately unsatisfactory. Others are convinced that Kant manages to refute the skeptic only with the Second Edition argument, the Refutation of Idealism. The Fourth Paralogism---the argument that Kant presents in 1781, but drops in the Second Edition---is usually dismissed because of its alleged commitment to phenomenalism that makes it unable to serve as the foundation of the existence of a mind-independent world. In contrast with both groups, it is argued that Kant does have a powerful argument against the skeptic, which, however, is not to be found in the Refutation of Idealism or in its refinements in the "Reflexionen," but in a line of thought contained in the Fourth Paralogism, properly interpreted in a non-phenomenalistic way. The Refutation of Idealism, despite its intuitive appeal, ultimately fails and can be salvaged only if anti-skeptical resources are borrowed from the Fourth Paralogism