Rudolf Steiner: "The manner in which a man's own being confronts him imaginatively depends entirely upon his soul. The point is that we alter our own being if we really get completely away from ourselves, if we work with all our energy to learn to know all our attributes that we can observe in ordinary life, the attributes we believe to be dreadful and possibly objectionable to other people. We must take serious note of these attributes that we carry about with us but really should not possess. We are naturally not concerned here with saying agreeable things but with speaking the truth objectively. We can rest assured that, if we will only go to work objectively, self-criticism will prove to be a full-time task, and only in the last extremity should we engage, as is rather commonly done by humanity, in criticism or judgment of others. He who occupies his mind much with others and criticizes them freely can be sure that he is far too little concerned with himself to enable him to clear away what must be cleared away if he is to see his own individuality in its true likeness. The reply to the oft-repeated query of why one does not progress, which by rights a man should answer himself, is obvious. He should refrain from all criticism of others except when outer necessity demands it. Above all, he should never forget what this “refrain” implies. It includes, for example, the occasional acceptance of something disagreeable or baneful. Certainly one must accept such things, but anyone who seriously believes in karma knows, naturally, that he brought all that on himself; karma placed the other man where he was in order that he might inflict the injury. A genuine personal reason for taking the world to task never really exists.
Why is this the case? We understand now that in the course of the cultural evolution of the Earth man must become, through many incarnations, what he will be able to be in some one future incarnation, and for this reason he has the longing to keep returning. In each incarnation he must long for what is impossible of achievement in a single Earth life. He must keep returning; then he can eventually become what it is possible to be in one incarnation. Precisely by acquiring the knowledge of and feeling for what he really should be in one life, but what he cannot be for inner — not outer — reasons, he knows what feeling must predominate in the soul when he passes through the portal of death. The predominating feeling must be a longing to return, in order to become, in the next life and in subsequent ones, what he could not become in one incarnation. This longing for ever new Earth lives must be the most powerful force. These thoughts can only be touched upon, but they yield the strongest confirmation of reincarnation."