of telepathy and/or clairvoyance. Now, these were things which he felt he could verify. Is it not extremely likely that when, mixed with these, he experienced the unverifiable, such as visions and apparent "other-world" phenomena, he concluded that they also were "real," since, as will be seen, he felt he had other reasons for thinking so?
Let the psychical research color be put over this puzzle, and something new may emerge.
To find out if extrasensory perception and precognition must at least provisionally be considered facts, it is necessary, as has been said, to make a careful study of the technical literature. Here only brief hints can be given of a couple of the objective methods which have been worked out by individuals or by groups, some working at colleges and universities.4
G. N. M. Tyrrell5 had five small boxes made, completely light-proof, and fitted with tiny electric lamps. A mechanical device selected at random which of the boxes was to be lit up when Mr. Tyrrell (the experimenter) from behind a screen pressed a noiseless key. At a given signal the subject of the experiment, or "sensitive," opened the lid of the box which she guessed to be the one lit up, another device automatically recording her choice and whether it was or was not correct. About seventy trials a minute were made. By another mechanism, which the experimenter could use without the knowledge of the subject, the lamp of the box opened by the subject was not actually lit until she lifted the cover.
The Tyrrell experiments were in fact safeguarded and tested in far greater detail than sketched here. Results achieved were far beyond chance, whether the lamp was lit before the cover was lifted, or simultaneously with the lifting. In a series of 7,809 trials, made with mechanically selected numbers, the odds against the results being due to chance were many millions to one.6 And, in a series of trials testing precognition by the subject of which box was going to be lit up, the odds against chance were likewise many million to one.
In the Soal and Goldney experiments7 carried on in England from 1941 to 1943, a specially gifted subject was tested for "precognitive telepathy" under the most elaborate precautions. In one room the subject, under observation by one experimenter, wrote his
