If guideline in two sciences to determine the possible terms that would give to metaphysics a science character: the mathematics and the physics. We can say that the mathematics is a true model for the modern philosophy, therefore offers, in the case of Kant, the principles and procedures that will become possible the construction of a solid building and the attainment of a rigorous method of inquiry. Throughout all the workmanship of the Critical one, is unequivocal the kantiana admiration for the mathematics, therefore it discloses how much the knowledge is capable to progress without the aid of the experience. The kantiano method can be called of reflexive, therefore when reflecting on the rational knowledge that we possess it is that we will get necessary idea of the proper nature of the reason. The reflection is the movement that the citizen, through its proper operations if return on itself, exactly on, therefore, to the critical idea.
The problem that Kant had to decide, gift in the Critical one of the Pure Reason, said respect to the following question: how I can get a safe and true knowledge on the things of the world? The reply of Kant it would go to change the route of the philosophy. As Kant in such a way in the case of the empiristas how much in the one of the racionalistas its conceptions concerning the way exist obstacles how much as to conceive the knowledge. The speculative reason of the rationalism, in the measure where it leaves to validate its inquiries in practical tests, became dogmtica. In turn, the empirismo finds opposition in the skepticism, that argues that the nature is the kingdom of the contingent and, therefore, it cannot be source of universal knowledge. David Hume placed under suspicion the beginning of causalidade, that it determines that, given a cause x, a effect y is had.
