Carl%20Sagan%20-%20The%20Demon%20Haunted%20World

THE DEMON-HAUNTED WORLD
And, after all, some illnesses are psychogenic. Many can be at
least ameliorated by a positive cast of mind. Placebos are dummy
drugs, often sugar pills. Drug companies routinely compare the
effectiveness of their drugs against placebos given to patients with
the same disease who had no way to tell the difference between
the drug and the placebo. Placebos can be astonishingly effective,
especially for colds, anxiety, depression, pain, and symptoms that
are plausibly generated by the mind. Conceivably, endorphins -
the small brain proteins with morphine-like effects - can be
elicited by belief. A placebo works only if the patient believes it's
an effective medicine. Within strict limits, hope, it seems, can be
transformed into biochemistry.
As a typical example, consider the nausea and vomiting that
frequently accompany the chemotherapy given to cancer and
AIDS patients. Nausea and vomiting can also be caused psychogenically,
for instance by fear. The drug ondansetron hydrochloride
greatly reduces the incidence of these symptoms; but is it
actually the drug or the expectation of relief? In a double-blind
study 96 per cent of patients rated the drug effective. So did ten
per cent of the patients taking an identical-looking placebo.
In an application of the fallacy of observational selection,
unanswered prayers may be forgotten or dismissed. There is a real
toll, though: some patients who are not cured by faith reproach
themselves - perhaps it's their own fault, perhaps they didn't
believe hard enough. Scepticism, they are rightly told, is an
impediment both to faith and to (placebo) healing.
Nearly half of all Americans believe there is such a thing as
psychic or spiritual healing. Miraculous cures have been associated
with a wide variety of healers, real and imagined, throughout
human history. Scrofula, a kind of tuberculosis, was in England
called the 'King's evil', and was supposedly curable only by the
King's touch. Victims patiently lined up to be touched; the
monarch briefly submitted to another burdensome obligation of
high office, and, despite no one, it seems, actually being cured,
the practice continued for centuries.
A famous Irish faith-healer of the seventeenth century was
Valentine Greatraks. He found, somewhat to his surprise, that he
had the power to cure disease, including colds, ulcers, 'soreness'
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