The aim of this article is to give an account of the changes Kant felt it was necessary to make in dogmatic metaphysics, concerning its searching for first principles. The changes had to be done in face of the attack the skeptics have made against this science. Their attack revealed the lack of justification for metaphics pretensions, for, in accordance to them, our mental faculties do not allow any claim to first principles, when these principles leave the domain of sense data. This attack puts metaphysics in a situation that the searching for first principles, that abandon sense data, could not have any kind of validity. Due to this, Kant accounts for the need of an investigation concerning our mental faculties, and concludes that, exactly due to those faculties, it is possible to give validity to the aims of metaphysics in such a searching. In the process of rearranging metaphysics natural claims to first principles, reflecting judgments will play a fundamental role.
