Pseudoscience consists of statements, beliefs, or practices that claim to be both scientific and factual but are incompatible with the scientific method. Pseudoscience is often characterized by contradictory, exaggerated or unfalsifiable claims; reliance on confirmation bias rather than rigorous attempts at refutation; lack of openness to evaluation by other experts; absence of systematic practices when developing hypotheses; and continued adherence long after the pseudoscientific hypotheses have been experimentally discredited.
The demarcation between science and pseudoscience has philosophical, political, and scientific implications. Differentiating science from pseudoscience has practical implications in the case of health care, expert testimony, environmental policies, and science education. Distinguishing scientific facts and theories from pseudoscientific beliefs, such as those found in climate change denial, astrology, alchemy, alternative medicine, occult beliefs, and creation science, is part of science education and literacy.
Pseudoscience can have dangerous effects. For example, pseudoscientific anti-vaccine activism and promotion of homeopathic remedies as alternative disease treatments can result in people forgoing important medical treatments with demonstrable health benefits, leading to deaths and ill-health. Furthermore, people who refuse legitimate medical treatments to contagious diseases may put others at risk. Pseudoscientific theories about racial and ethnic classifications have led to racism and genocide.
The term pseudoscience is often considered pejorative particularly by purveyors of it, because it suggests something is being presented as science inaccurately or even deceptively. Those practicing or advocating pseudoscience therefore frequently dispute the characterization.
In France widespread use of graphology, numerology and astrology by personnel managers and employment agencies as a means of revealing character or analysing business opportunities. Studies indicate that in 1993 most private or state-owned corporations routinely used graphologists. Unknowingly a significant portion of the French population has been subjected to an invasive procedure that has no established scientific value. Applications for senior management positions are routinely sent off for analysis by specialists in such disciplines.
Black Hebrew Israelites, a black supremacist group in the US, typify the use of numerology from the Book of Revelation. They believe group members will comprise the 144,000 people who are saved by God in the second coming that is outlined in Revelation (7:1-17). In the Book of Revelation, John is shown a vision of 144,000 martyrs who have survived and did not submit to Satan. This number is derived from the assertion that the twelve tribes of Israel consisted of 12,000 people each.