§3.1 will now give a group of cases in respect of which the hypothesis of mistaken identity has to be taken into account. The apparition in all of them was seen out-of-doors, and in several of them in the street - which is the place where such mistakes are most liable to occur. Now, with respect to mistakes of identity, made at the time when the person who seems to be seen is really dying at a distance, one general remark has to be made - namely, that cases in which they have occurred are not thereby at once put out of court, for the purpose of my argument. For if telepathic hallucinations are facts in nature, the possibility of telepathic illusions cannot reasonably be excluded. Illusions, as I have remarked (p. 288), are merely the sprinkling of fragments of genuine hallucination on a background of true perception; and it is surely not more difficult to suppose that a mind which is telepathically affected can project its sensory delusion on some real figure which bears a general resemblance to the agent, than that it can project it in vacancy.

But of course the coincidence with A's death of an illusion in which the perceiver mistook B for A would have far less force as evidence for telepathy than the coincidence with A's death of a hallucination representing him, simply because purely subjective mistakes as to identity are far commoner things than purely subjective hallucinations. To find the probability that a person will by accident make a particular mistake of identity on a particular day of his life, we must multiply the fraction 1/number of days of his life by the number of similar mistakes, in similar circumstances of light, distance, etc., that he makes altogether; and we must divide the result by the number of acquaintances any one of whom, if chance alone acted, is as likely as the one who died on the particular day to be the one wrongly identified on that day. This process may reduce the probability of a telepathic explanation of the coincidence from odds of millions to 1 (as found in the case of hallucinations) to odds of thousands to 1; but in a cumulative argument, odds of that magnitude are clearly not to be neglected. However, with regard to the following specimens, or most of them, such considerations are hardly needed.

They seem pretty certainly to be cases of hallucination, and stand, for instance, on different ground from the incidents mentioned above (p. 103), where the hypothesis of mistaken identity seemed fairly plausible.

The first account is from the Chevalier Sebastiano Fenzi, of the Palazzo Fenzi, Florence, a corresponding member of the S.P.R. The peculiar melancholy described as preceding the vision may possibly exemplify the gradual emergence of telepathic impressions into consciousness, winch was exemplified in Chapter XII (The Development Of Telepathic Hallucinations), § 3.

"November 13th, 1883.