Duas coisas enchem o ânimo de admiração: o céu estrelado acima de mim, e a lei moral dentro de mim; ambas não estão fora do meu horizonte; antes, vej… - Immanuel Kant

That religion in which I must know in advance that something is a divine command in order to recognize it as my duty, is the revealed religion (or the one standing in need of a revelation); in contrast, that religion in which I must first know that something is my duty before I can accept it as a divine injunction is the natural religion. … When religion is classified not with reference to its first origin and its inner possibility (here it is divided into natural and revealed religion) but with respect to its characteristics which make it capable of being shared widely with others, it can be of two kinds: either the natural religion, of which (once it has arisen) everyone can be convinced through his own reason, or a learned religion, of which one can convince others only through the agency of learning (in and through which they must be guided). … A religion, accordingly, can be natural, and at the same time revealed, when it is so constituted that men could and ought to have discovered it of themselves merely through the use of their reason, although they would not have come upon it so early, or over so wide an area, as is required. Hence a revelation thereof at a given time and in a given place might well be wise and very advantageous to the human race, in that, when once the religion thus introduced is here, and has been made known publicly, everyone can henceforth by himself and with his own reason convince himself of its truth. In this event the religion is objectively a natural religion, though subjectively one that has been revealed.

"The purpose of this critique of pure speculative reason consists in the attempt to change the old procedure of metaphysics, and to bring about a complete revolution after the example set by geometers and investigators of nature. This critique is a treatise on the method, not a system of the science itself; but nevertheless it marks out the whole plan of this science, both with regard to its limits and with regard to its inner organization. For it is peculiar to pure speculative reason that it is able, indeed bound, to measure its own powers according to the different ways in which it chooses its objects for thought, and to enumerate exhaustively the different ways of choosing its problems, thus tracing a complete outline of a system of metaphysics. This is due to the fact that, with regard to the first point, nothing can be attributed to objects in *a priori* knowledge, except what the thinking subject takes from within itself; while, with regard to the second point, pure reason, as far as its principles of knowledge are concerned, forms a separate and independent unity, in which, as in an organized body, every member exists for the sake of all the others, and all the others exist for the sake of the one, so that no principle can be safely applied in *one* relation unless it has been carefully examined in *all* its relations to the whole use of pure reason. Hence, too, metaphysics has this singular advantage, an advantage which cannot be shared by any other rational science which has to deal with objects (for *logic* deals only with the form of thought in general), that if by means of this critique it has been set upon the secure course of a science, it can exhaustively grasp the entire field of knowledge pertaining to it, and can thus finish its work and leave it to posterity as a capital that can never be added to, because it has to deal only with principles and with the limitations of their use, as determined by these principles themselves. And this completeness

From this it follows incontestably, that pure concepts of the understanding never admit of a transcendental, but only of an empirical use, and that the principles of the pure understanding can only be referred, as general conditions of a possible experience, to objects of the senses, never to things in themselves…