The discipline of science, including the medical sciences, responds with difficulty and considerable delay to new classes of phenomena which are not easily explained within its existing paradigms. Given the authority with which it speaks in initially condemning such phenomena as illusions, coincidences, inadequately substantiated, not subject to experimentally verification, or simply the result of deliberate fraud, such procrastination delays the advance of knowledge and marginalizes those who endeavour to explore such phenomena using different paradigms.
Classical examples include scientific proofs that objects heavier than air cannot fly and the response to hypnotism. Continuing difficulties are experienced with homeopathy, extrasensory perception, radiesthesia, acupuncture and UFOs. Such difficulties are experienced to different degrees by different schools of science. Scientists in socialist countries have much greater legitimacy in exploring extrasensory perception, for example, than those in western countries who have little tolerance for such phenomena. Another aspect is the difficulty of accepting evidence for health hazards associated with long term exposure to low levels of chemicals or radiation.