Gurney discusses the phenomenon and its probable causes. We know, of course, that hallucinations are among the most common of psychic phenomenon. Your subconscious mind can be caused to see and hear and feel anything; likewise it has power to cause you to see and hear and feel anything. In practically all cases of multiple personality some of the split-off personalities can cause the others to see and hear and feel. And the consciousness, you must understand, takes these things to be just as real as real things; there is no way you can tell an hallucination from reality--except to ask other people about it. And if we admit the idea of telepathy, we may say that phantasms are hallucinations caused by this means; that is, the subconscious mind of your wife or your mother or your friend who is ill or dying, transmits to your subconscious mind some vivid impression, which causes your own subconscious mind to present to your consciousness a perfect image of that person, walking and talking with you, and your consciousness has no way of telling but that the image is real. So much for phantasms of the living. But are there any phantasms of the dead? Are there any cases in which the time of the appearance can be proven to be subsequent to the time of death? Even this would not prove survival, of course; it is perfectly possible that the telepathic impulse might be delayed in our own minds, it might not flash into consciousness until our own state of mind made it possible. Can we say that there are cases in which the facts communicated are such as to convince us that the person was already dead, and was telling us something as a dead person and not as a living one? Before we go into this question, let us clear the ground for the subject by discussing the survival of personality from a more general standpoint. What is it that we want to prove? What are the probabilities of its being true? What would be the consequences of its not being true? Have we any grounds, other than those of psychic research, for thinking that it is true, or that it may be true, or that it ought to be true? What, so to speak, are the morals of the doctrine of immortality?