ESP (EXTRASENSORY PERCEPTION)

The ability to perceive information without the benefit of the senses.
Such perceptions, collectively called PSI phenomena, are grouped in
four main categories: telepathy, or mind-to-mind communication;
clairvoyance, or the awareness of remote objects, persons, or events;
precognition, or the knowledge of events lying in the future; and
retrocognition, or the knowledge of past events in the absence of
access to information about those events.

Scientific theory does not recognize modes of perception other than
those mediated by the sense organs and other body systems, so ESP by
definition lies outside the realm of scientific explanation. Claims
for the occurrence of ESP therefore remain controversial, although the
converse condition also holds, that the existence of ESP cannot
positively be disproved.

In the twentieth century, attempts at controlled study of ESP
phenomena have been undertaken by various persons and groups (see
parapsychology). Such researchers often claim that ESP experiences can
be induced by hypnosis, chemicals, or other artificial means so that
they can be measured precisely under laboratory conditions. The
scientific community as a whole does not accept ESP research reports,
because it does not find them verifiable or reproducible.
Parapsychologists and others, however, maintain that ESP exists and
should be explored even should it remain beyond the bounds of
scientific understanding.

The number of ESP experiments in modern times is enormous. Relatively
few have been conducted under proper supervision, and it must be
admitted that some have been found to have involved cheating. For
example, one of the first properly recorded tests was arranged in
1882, soon after the formation of the British Society for Psychical
Research, when its first President, Henry Sidgwick, announced that the
five young daughters of an English clergyman had convinced independent
investigators of their telepathic abilities. However, six years later
they were caught using a code to communicate with each other.

A more successful experiment in telepathy was conducted in 1937 by
Harold Sherman and Sir Hubert Wilkins, when Wilkins, an Australian
explorer, was hired by the Russians to find a pilot who had
disappeared in the Arctic. Sherman suggested to Wilkins that during
his trip they should try to communicate by telepathy. Three days each
week Wilkins sat down and reviewed the day's events; in New York,
Sherman sat in near-darkness and wrote down anything that came into
his head. Among other incidents, Sherman learned of a fire at a place
called Aklavik before the news came by radio.

There have been some spectacular results under strictly controlled
conditions. One of the most famous was reported in 1937 by Professor
Riess of Hunter College, New York. On a number of evenings, Riess
turned face-upward a series of cards from a newly shuffled pack on his
desk, and his subject wrote down the cards that came to mind. Two
packs of 25 cards were used each day. Gradually, the subject became
more accurate; and on the last nine days of the experiment her score
of successes was 17, 18, 19, 20, 20, 19, 20, 21 and 21 â€" so far
above chance as to be astonishing, and by far the highest score ever
recorded in a series of ESP experiments.