These "spirits" apparently desire to convince us of their reality, and they tell us many things which are expected to convince us; they tell us things which we ourselves do not know, and which spirits might know. But here again we run up against the problem of the subconsciousness, with its infinite mass of "forgotten" knowledge. It is not so easy for the "spirits" to tell us things which we can be sure our subconscious mind could not possibly contain. Also, there comes the additional element of telepathy. It appears to be a fact that under trance conditions, or under any especially exciting conditions of the consciousness, one mind can reach out and take something out of another mind, or one mind can cause something to be passed over to another mind; and so information can be communicated to the mind of a medium, and can appear in automatic writing, or in clairvoyance, or in crystal gazing. One of the most conscientious and earnest of all the investigators of this subject was the late Professor Hyslop, who many years ago sought to teach me "practical morality" (from the bourgeois point of view) in Columbia University. Professor Hyslop worked for fifteen years with a medium by the name of Mrs. Piper, who was apparently sincere and was never exposed in any kind of fraud. In Professor Hyslop's books you will find innumerable instances of amazing facts brought out in Mrs. Piper's trances. You will find Professor Hyslop arguing that the only way telepathy can account for these facts is by the supposition that there is a universal subconscious mind, or that the subconscious mind of the medium possesses the power to reach into the subconscious mind of every other living person and take out anything from it. But for my part, I cannot see that the case is quite so difficult. Professor Hyslop recites, for example, how Mrs. Piper would tell him facts about some long dead relative--facts which he did not know, but was later able to verify. But that proves simply nothing at all, because there could be no possible way for Professor Hyslop to be sure that he had never known these facts about his relatives. The facts might have been in his subconscious mind without having ever been in his conscious mind at all; he might have heard people talking about these matters while he was reading a book, or playing as a boy, paying no attention to what was said. And then came Sir Oliver Lodge with his investigations. I will say this for his work--he was the first person who was able to make real to my mind the startling idea that perhaps after all the dead might be alive and able to communicate with us. You will find what he has to say in his book, "The Survival of Man," and it seems fair that a great scientist and a great man should have a chance to convince you of what seem to him the most important facts in the world.