One of these causes is this, that both the believers and the unbelievers are firmly convinced that Christ's teaching has been comprehended by them long ago, and so completely, indubitably, and finally, that there can be no other meaning in it than the one they ascribe to it. This cause is due to the duration of the tradition of the false comprehension, and so of the failure to understand the true teaching. The most powerful stream of water cannot add a drop to a vessel that is full. It is possible to explain the most intricate matters to a man of very hard comprehension, so long as he has not formed any idea about them; but it is impossible to explain the simplest thing to a very clever man, if he is firmly convinced that he knows, and, besides, incontestably knows, what has been transmitted to him. The Christian teaching presents itself to the men of our world precisely as such a teaching, which has for a long time and in a most indubitable manner been known in its minutest details, and which cannot be comprehended in any other manner than it now is. Christianity is now understood by those who profess the church doctrines as a supernatural, miraculous revelation concerning everything which is given in the symbol of faith, and by those who do not believe, as an obsolete manifestation of humanity's need of believing in something supernatural, as a historical phenomenon, which is completely expressed in Catholicism, Orthodoxy, Protestantism, and which has no longer any vital meaning for us. For the believers the meaning of the teaching is concealed by the church, for unbelievers by science. I shall begin with the first: Eighteen hundred years ago there appeared in the pagan Roman world a strange, new teaching, which resembled nothing which preceded it, and which was ascribed to the man Christ. This new teaching was absolutely new, both in form and in contents, for the European world, in the midst of which it arose, and especially in the Roman world, where it was preached and became diffused.