" The placebo effect is well documented and not even very mysterious. Dummy pills, with no pharmacological activity at all, demonstrably improve health. That is why double-blind drug trials must use placebos as controls. It’s why homoeopathic remedies appear to work, even though they are so dilute that they have the same amount of active ingredient as the placebo control—zero molecules. "

― Richard Dawkins , The God Delusion