“When you put it in that way, Thorwald,” replied the doctor, “I begin to see how unreasonable my position must appear to you. But, however pleasant the idea, I do not see how I can believe that other worlds are inhabited without more evidence than we now possess. This is speaking, of course, without the knowledge we have gained since coming here. But I do not mind saying that your talk has made me wish I could believe it.” I was glad for several reasons that the doctor acknowledged as much as this. First, for Thorwald’s sake; for I had been thinking the doctor’s obduracy was proving a poor reward for our friend’s great kindness to us. I rejoiced, too, that my companion was beginning to show our new acquaintance that, although he had little imagination, he was possessed of a good heart. And, finally, I was myself so much in sympathy with Thorwald’s views that I was glad to see his arguments begin to make some impression on the doctor’s mind. But now it seemed to me that Thorwald had much to tell us from his own experience. He had talked so far on this subject from the standpoint of our earthly knowledge, but had hinted more than once that the inhabitants of Mars had more positive evidence than we had ever dreamed could be possible. So I said: “Your arguments have been very acceptable to me, Thorwald, but can you not strengthen even my faith by speaking now from the results of your own more advanced studies? We must base our belief in the existence of life outside the earth on mere probabilities, which, however strong, lead only to theory and leave us still in doubt. Have you any certain knowledge on the subject, or, I might say, had you any before we came to see you?” “Oh, yes,” replied Thorwald, “we have long had evidence almost as positive as your presence here, fresh from one of our sister planets. It will give me great pleasure to tell you of some of our marvelous achievements in astronomy. The doctor says he would like to believe in the habitability of other worlds; he must believe in it before I am through if he has any faith in me. “I would like to say, to begin with, that whatever we have accomplished in this science you on the earth can accomplish. I know enough by comparing your development with our own to feel sure that our present condition foreshadows yours, and that all the knowledge we possess in various directions will come in time to you. Let nothing discourage you in your quest for knowledge. If you seem to have arrived at the limit of possibilities in the telescope, for example, have patience. Difficulties which you think insurmountable, time will remove, and you will be able to penetrate more and more into the mysteries of the universe.