But knowledge can be divided into two aspects: one aspect is the knowledge which we call learning; the other aspect is knowing. Learning comes from the reason:'It is so, because of this or that"; that is knowledge. But there is a knowing which cannot be explained by "because"; it can only be said that it is so; it cannot be anything else. The knowledge with its "because" attached, is contradicted a thousand times over. One scientist, one inventor, one learned person has one argument; another comes and he says, "This is not what I think; I have found out the truth about it, which the one who looked before did not perceive rightly." It has always been and will always be so with the outer knowledge.