Pseudoscience is a body of knowledge which presents itself with a veneer of scientific respectability which does not hold up under scrutiny. The term “pseudoscience” is meant to be derogatory; you may also hear terms like “alternative science” or “junk science” used to refer to such fields. Learning to distinguish true science from pseudoscience is very important.
The key characteristic of pseudoscience is that it does not conform with the scientific method. This means that pseudoscientific claims cannot be tested, and do not follow a logical order. Plenty of scientific concepts cannot be tested with existing equipment, but the originators of such theories can provide solid information which supports their hypotheses, and these creators also welcome critiques and honest analysis. Pseudoscience has no scientific backing, and it cannot be tested.
Several key things can be used to identify a field of knowledge or a claim as pesudoscience. The first is the lack of testability and independent confirmation. True scientists are always happy to share the data they used to arrive at their conclusions, and they welcome independent testing and critiques of their work, using refutation as the primary tool to prove a theory, rather than seeking out proofs. The pseudoscience community rejects refutation, preferring to seek out evidence which bolsters specific claims, and it is not open to scrutiny or discussion.
It is also common to see pseudoscience accompanied with grandiose languages and claims which are heavily exaggerated. Misleading language is often used in a pseudoscientific argument, and the author may make an argument which is based in ignorance, or in an assumption that the reader will be ignorant. Contradictory claims and arguments are also common, along with a generally poor sense of organization and thought.
The research used to support pseudoscience is typically very sloppy, which means that it cannot be verified or repeated. In addition, pseudoscience is usually accompanied with a general lack of progression, and it is often highly personalized. When people raise valid questions or critiques, they are accused of personal attacks, coverups, or conspiracies. This hostile attitude to criticism can be the undoing of pseudoscientists, even if their claims could potentially have some validity if they were tested empirically.
Many professional scientists regard pseudoscience as very harmful, in addition to irritating. Consumers spend large amounts of money on pseudoscience every year, believing the grandiose claims made by companies attempting to turn a profit, and pseudoscience can infiltrate society to an alarming level. At one time, for example, people genuinely believed in the practice of phrenology, which involves examining the bumps on someone’s head to determine his or her inner nature.