An important series of ESP tests by the English mathematician Dr. Soal carried on the work began by J.B. Rhine. Soal's series of experiments is generally conceded to be the most cogent of all the evidence brought forth to demonstrate the theory of psychic abilities in mankind. In view of Dr. Soal's reputation for painstaking patience and the elaborate lengths to which he has gone to eliminate sensory cues, many psychic investigators believe that the proof of ESP stands or falls by these experiments (which are by far the most interesting and convincing of all ESP experiments carried out in America or England). It was these experiments that gained for the psychic investigator from London University the degree of Doctor of Science.

A hypothesis of genuine prophetic abilities seems the only way of explaining the curious experimental results obtained. The apparent prophetic ability of Soal's subject appeared quite unexpectedly, and was hailed, not only as an excellent demonstration of psychic powers of the mind, but as a final safeguard against the possibility of the experimental results being brought about by sensory cues.

What, it is asked, can rationally account for the fact that one man can think what is about to enter the mind of another throughout thousands of tests, when all sensory cues are excluded? This is the situation which has faced the skeptics. Fraud or collusion may be an answer, but this hypothesis is extremely unlikely. The records of the experiment together with their statistical analysis may confidently be accepted as valid. The only question involved is what interpretation should be given to the results?

According to an analysis by D.H. Rawcliff, "Soal has overlooked certain possibilities in regard to the transmission of sensory cues from agent to percipient; while guarding effectively against sensory cues occurring between two individuals, he overlooked the fact that what may appear to be impossible between two persons may well be possible when three are involved"

Rawcliffe goes on to say that Rhine and his American counter-parts in ESP research should be dismissed as "unacceptable on collateral evidence of bias and tendentiousness. Rhine and his colleagues were guilty of partisan prejudice in the selection, presentation and interpretation of experimental results. In the ESP experiments of Dr. Soal, this presentational bias largely disappears, the reports are more objective.

Soal's experiments were experiments in telepathy. That is to say, they were carried out to test a theory that one human mind could interact directly with another in some kind of way other than through the senses.

In Soal's experiments, as in the usual run of telepathic experiments by psychic investigators, the sensitive" or "subject" had to guess the symbols or pictures in a pack of cards upon which another person known as the "agent" was fixing his gaze. This type of experiment is very different from most of those undertaken by Dr. Rhine and the American ESP experimenters, who concentrated on a "clairvoyance" type of test where the subject's supposed psychic ability is expected to help him or her identify the cards in question without the aid of another mind. Soal himself has found no evidence of clairvoyance in his own experiments.

Soal was granted a Doctor of Science degree by London University for his investigation of telepathy. In 1947 the Central Research Fund of London University awarded him a money grant for the continuation of his work and for the purchase of apparatus.

By 1939 Soal had been experimenting in card guessing experiments for over four years in an attempt to find confirmation of the frequent successes in "extra-sensory perception" published by Rhine and others at Duke University in America. He had tested 100 different subjects and had recorded 128,000 guesses without the slightest indication of ESP, he was beginning to arrive at the conclusion that the quest was a dead-end. The important thing about these four years of negative ESP tests is that it establishes Soal as a bonifide psychic investigator. It clearly demonstrates his patience, integrity, and high standard of experimental control which is unusual for most ESP researchers.

Soal's patience, however, had its reward. Another ESP researcher, Whately Carington, mentioned that he had found evidence of "displacement", and encouraged Soal to check through his own records for this same effect. By "displacement" we mean that the records of the ESP subject show a tendency to guess the next card correctly, not the card that he/she is supposed to be guessing. Out of 160 subjects that Soal had tested, the records of two of them show marked evidence of the subjects having scored above chance on the cards which came either before or after the target card.