If the 1894 survey of hallucinations is anything to go on, one in ten of you has encountered by sight, sound, touch, or smell something which, on reflection, you realised was not physically present. In other words, a ghost. Since life is not yet over, no doubt even more will have the experience before they expire. In most cases, it will be something they saw. But how many of you have heard a voice from out of nowhere? And if you did, how did you react? I have heard more than one such incident. Here is a good example.
