Question: The appearance of 'doubles' is a well-established fact. Sometimes they appear only when the person duplicated is in a trance or asleep, but also, not infrequently, when he is awake, when he is actively engaged, and when the person to whom, and the place where, his double appears are not present in his thought. These doubles often appear by daylight, and to several persons at once, and thus seem to have some objective existence. The question I wish to ask is, are these 'doubles' always, or ever, produced by independent spirits to whom his peculiar condition at the time affords the opportunity for their production? If they are produced by the exclusive agency of the person himself, how are they produced when there is no wish or conscious agency on his part? And how are they produced even when there is such a wish?--Alfred R. Wallace.

     Reply [[by the Editor]]: The appearance of the 'double' is a fact associated with the existence of a realm of subjective activity, pertaining alike to the individual and the, so called, material universe. Such appearances necessarily involve the existence of these possibilities in man, and of a plane upon which such possibilities can be expressed. Further, the existence of such a plane also implies that those who see the 'double' are also in relation to the conditions pertaining to that plane. This being understood, the points involved in the question are well taken, and may be thus dealt with:--The 'double' is not always produced by--that is, not always a projection of--the person it represents, but may be a representation flashed upon the consciousness of the person to whom it is manifested, in which case an impression, of sufficient intensity to become mentally visualised by the percipient, is made upon the mind. The result is more in the nature of a vision, and cannot justly be called a 'double' in the ordinary sense. But such results are only possible 'when the peculiar condition' of the percipients affords the opportunity for the production of such phenomena, and what that 'peculiar condition' may be depends entirely upon the circumstances of the time. In the next case, as stated in the question, from the fact that all are, in varying degrees, more or less unconsciously active on the subjective plane--unconscious to the external cognition--it follows that, at times, the percipient and not the projector of the 'double' may come into contact with the sphere of the person whose 'double' he sees, and, not being trained in this kind of experience, naturally reverses the order of events, and concludes that the 'double' has come to him, rather than, so to speak, that he has gone to the 'double.' Where 'doubles' are seen by several persons at the same time and place, there is, usually, a certain tangibility in the appearance, and it then approximates to the nature of an apparition--i.e., 'ghost'--and its appearance verges on the conditions pertaining to materialisation. That the party concerned is either asleep, in a trance, or otherwise unconscious of the matter is, of course, the evidence that the subject pertains to man's subjective faculties, as already stated.