This is a list of substances or materials generally considered discredited.
A substance can be discredited in one of three ways:
It was widely believed to exist at one time but no longer is. Such substances are often part of an obsolete scientific theory. It was once believed to have drastically different properties from those accepted now. It was widely claimed and believed to possess significant properties that are no longer attributed to it. It is currently believed to exist as part of a theory that has not met the theoretical and experimental requirements of mainstream science. In particular, such a theory must be predictive.
Substances whose existence is discredited
SubstanceTheorized byFrom whenAlleged definitionDiscredited byAether (classical element) Ancient times The medium filling the universe above the terrestrial sphere enabling transmission of light and gravityThe Michelson–Morley experimentAlicorn Ancient timesThe horn of the unicorn, has mystical healing propertiesNever foundAlkahestParacelsus1493–1541A universal solvent, which can dissolve every other substance, including goldNever found (note that aqua regia can dissolve gold, but not everything)AndrewsiteThomas Andrews 1871–1990 Green mineral named for Thomas Andrews Confirmation in 1990 that the substance is composed of other mineralsCaloricAntoine Lavoisier1783Weightless fluid, the substance of heatHeat came to be interpreted as the energy of the motion of atomsCoroniumCharles Augustus Young and William Harkness1869Chemical element in the solar coronaIn the 1930s, Walter Grotrian and Bengt Edlén discovered that the spectral line in question was due to highly ionized ironÉlan vitalHenri Bergson1907Substance or force bearing the property of lifeMolecular biologyElixir of lifeMythologyAncient timesSubstance believed by alchemists to confer immortalityNever foundErototoxinsJudith Reismanafter 1955Addictive chemicals produced in the brain by pornographyAddictive opioids (i.e. endorphins) in the brain are related to pleasure in general, not specific to pornographyNair, Mohan; Friedman, Rob; Maram, Wesley. "I20 Pornography and Sexual Violence: Is There a Connection?", Seattle 2010, Forensic Psychiatry and Behavioral Science, 2002-2011 Proceedings of the American Academy of Forensic Sciences, p. 28.Luminiferous aether 18th centuryMedium for the propagation of lightMichelson–Morley experimentMiasma Ancient timesFoul smell believed to carry diseasesModern biology, in particular the discovery of actual infectious agentsNebuliumWilliam Huggins1864An element in the Cat's Eye NebulaIn 1927, Ira Sprague Bowen showed that the observed spectral lines are emitted by doubly ionized oxygenN-raysProsper-René Blondlot1903A form of radiation emitted by most substancesA simple null experiment, where Blondlot thought he could see the effects of N-rays even when an essential component had been removed from the experimental apparatusOdic forceCarl Reichenbach1845Force bearing the property of lifeLack of experimental evidence and any predictive theory; never accepted by scienceOrgone energyWilhelm Reich1930sEnergy bearing the property of lifeLack of experimental evidence and any predictive theory; never accepted by sciencePanaceaAlchemistsAncient timesSubstance curing all illnessModern biology and medicinePhilosopher's stoneAlchemistsAncient timesLegendary substance that could transmute lead into precious metalsTransmutation requires nuclear processes. The first synthesis of gold was conducted by Japanese physicist Hantaro Nagaoka in 1924, who synthesized gold by bombarding mercury with neutrons.PhlogistonJohann Joachim Becher1667Weightless substance present in combustible materials and released when they are burnedModern chemistry, specifically the discovery that combustion is the combination of various substances with oxidizers, most commonly oxygenPolywater late 1960sA polymerised form of waterMore careful experiments with rigorously cleaned glassware showed that it was just contaminated waterPtomaines Alkaloids found in decaying matter thought to cause food poisoningDiscovery of bacteria (Germ theory of disease)Red mercuryHoax1979Controversial substance supposedly of use to terroristsIts actual nature, if any, is unclear. The notion may have been invented for use by Soviet and Russian sting operations targeting nuclear materials trafficking. It is also possible that the phrase may have originated as a codeword in Soviet nuclear weapons development, much as the word "copper" was once used to obfuscate "plutonium" during the Manhattan Project.
Substances whose properties are discredited This is not to be construed as implying that these items––are discredited. What is listed are fire, water, metal, etc. as universal principles or fundamentals. Classical elements and Chinese elements discredited by atomic theory and nuclear physics. Fire (classical element) Water (classical element) Earth (classical element) Air (classical element) Wood (classical element) Metal (classical element) Aether (classical element): Now known not to exist (see above) The four bodily humours: Blood, Phlegm, Black Bile, and Yellow Bile. Fluids believed to determine health and character. Discredited by modern biology, including discovery of hormones. The tria prima of Paracelsus and later alchemy: Salt, Mercury and Sulphur. Discredited by modern chemistry (the atomic theory and modern understanding of elements and compounds).
See also List of fictional elements, materials, isotopes and subatomic particles List of misidentified chemical elements
References