95 Times Scientific Consensus Was Wrong

Scientific consensus evolves over time as new evidence is gathered. Unsurprisingly, there are periods of time when initial scientific discoveries or ideas face significant skepticism or are not widely accepted. Some ideas now accepted were once rejected by the scientific community, in some cases for hundreds of years. Conversely, wrong ideas were widely accepted, sometimes for centuries. In some cases the discoverers died in poverty and obscurity, never aware that they had helped eventually change the world. This does not mean that every theory scientists reject will be true some day. It does means one must look carefully at the details of arguments and at supporting data. The majority scientific view can be and has been wrong many times over the centuries, so keep an open mind and follow the facts.

Here is a small dictionary of cases where the majority of the scientific community at one time rejected something which they now accept, or vice versa. These examples illustrate instances where scientific consensus evolved or changed due to new evidence, experimentation and advances in knowledge. It highlights the continuous nature of scientific inquiry, where ideas can be refined and updated as new information becomes available. After scanning this list, you will hopefully wonder what things we now accept as true might one day be overturned.

A Sampler of Wrong Science Consensus

1. Acid rain: In the 1970s, the scientific consensus did not fully acknowledge the harmful effects of acid rain on ecosystems. However, studies on forest decline and the chemical composition of rainwater provided compelling evidence, leading to a shift in consensus towards recognizing the issues associated with acid rain.
2. Antibiotic resistance transfer between bacteria: The concept of horizontal gene transfer, specifically for antibiotic resistance genes, was initially met with resistance. Evidence from studies demonstrating gene transfer mechanisms and the rapid spread of antibiotic resistance genes later changed the scientific consensus.
3. Anorexia nervosa and Bulimia nervosa, Prevalence of : Initial skepticism surrounded the existence and understanding of these disorders.
4. Asbestos, Link to lung diseases: The dangers of asbestos were not initially recognized, and it was widely used in various industries. As evidence of its association with lung cancer, mesothelioma, and other respiratory diseases accumulated, the scientific consensus shifted towards acknowledging the harmful effects of asbestos.
5. Atoms, Existence of: Ancient Greek philosophers questioned the existence of atoms, believing matter to be continuous. However, evidence from numerous experiments, such as Brownian motion, the photoelectric effect, and Rutherford’s gold foil experiment, established the existence of atoms, leading to the modern atomic theory.
6. Avian influenza transmission to humans: Initially, it was thought that avian influenza viruses could not easily infect humans. However, outbreaks like H5N1 and H7N9, along with subsequent research, demonstrated that transmission is indeed possible.
7. Bacterial cause of tooth decay: Despite compelling evidence, skepticism initially surrounded this idea. Experiments with dogs showed that without both sugar and s. mutans bacteria, dog’s teeth would not get cavities and this lead to an understanding that bacteria make acid which causes demineralization of tooth enamel.
8. Big Bang theory: The scientific consensus that the universe was steady-state was overturned by the discovery of the cosmic microwave background radiation in 1965. This evidence supported the Big Bang theory and changed the prevailing view of the universe’s origin.
9. Black holes: Initially met with skepticism, the concept gained acceptance with research advancements. The discovery of X-ray emissions from compact objects and the detection of gravitational waves from merging black holes have provided strong supporting evidence for their existence.
10. Blackbody radiation: In the late 19th century, the scientific consensus was that the observed blackbody radiation could be explained by classical physics. This view was overturned by Max Planck’s revolutionary work in 1900, when he introduced the concept of quantization to explain the observed ultraviolet catastrophe. His theory, now known as Planck’s law, provided strong evidence that energy was quantized, the beginning quantum mechanics.
11. Brain Cell Regeneration: The previous scientific consensus suggested that brain cells, specifically neurons, do not regenerate in adult mammals. However, groundbreaking studies conducted in the late 1990s challenged this belief. The evidence came from a series of experiments involving the labeling of neurons and the identification of new cell formation in regions of the adult brain responsible for memory and learning, which ultimately overturned the prior scientific consensus on brain cell regeneration.
12. Brain plasticity: The long-standing consensus was that the adult brain was largely static and incapable of significant structural changes. The discovery of neuroplasticity, the brain’s ability to reorganize and form new neural connections throughout life, challenged this consensus, highlighting the brain’s adaptability.
13. Breastfeeding, Benefits of: Historical perspectives often downplayed the benefits of breastfeeding and favored formula feeding. However, subsequent research demonstrated the numerous advantages of breastfeeding, influencing a paradigm shift in infant feeding recommendations.
14. Caloric Theory: In the late 18th century, the caloric theory suggested that heat was a fluid-like substance called caloric that flowed from hotter to cooler bodies. The experiments of James Prescott Joule and others, demonstrating the conversion of mechanical work into heat, led to the abandonment of this theory for the modern understanding of heat as energy.
15. Cholesterol and heart disease: The scientific consensus once held that dietary cholesterol played a significant role in increasing blood cholesterol levels, ultimately leading to heart disease. New research and meta-analyses have since shown that the impact of dietary cholesterol on blood cholesterol levels is relatively small, leading to a shift in nutritional recommendations.
16. Climate Change, Human-induced: While widely accepted now, skepticism persisted for some time. Evidence such as temperature records, ice core data, and computer models overwhelmingly support the understanding that human activities are causing climate change.
17. Comets, Existence of: Initially met with skepticism, comets are now well-documented celestial objects.
18. Continental drift: Similar to plate tectonics, the hypothesis suggested by Frank Bursley Taylor faced initial rejection.
19. Cosmic microwave background radiation: Skepticism surrounded this discovery supporting the Big Bang theory. The cosmic microwave background radiation was discovered in 1965, providing strong evidence that supports the Big Bang theory. This radiation, predicted by George Gamow, Ralph Alpher, and Robert Herman, helped overturn the previously dominant static universe model.
20. Cosmic ray origin: The origin of cosmic rays faced skepticism until further research was conducted.
21. Dark matter: The scientific consensus on the composition of the universe was challenged by the discovery of dark matter’s gravitational effects in the 20th century. The evidence, including the rotational velocities of galaxies and gravitational lensing indicated the presence of unseen matter.
22. Dark energy: The concept of dark energy faced skepticism before more evidence was gathered.
23. Deep-sea hydrothermal vents: The existence of these vents faced skepticism due to the absence of sunlight.
24. DNA double helix structure: James Watson and Francis Crick’s model faced initial resistance.
25. DNA, Primacy as hereditary material: Before the discovery of DNA’s structure, the scientific consensus favored proteins as the hereditary material. The evidence presented by James Watson, Francis Crick, and Rosalind Franklin on DNA’s double helix structure overturned the existing consensus. Experiments by Alfred Hershey, Martha Chase and others identified as DNA the primary hereditary molecule.
26. Doppler effect: The concept of frequency shifts faced skepticism initially.
27. Earth’s Age: The scientific consensus once held that the Earth was a few thousand years old based on various religious and philosophical beliefs. However, the discovery of radiometric dating techniques in the early 20th century and analysis of geological formations provided overwhelming evidence for an Earth age in the billions of years.
28. Earth’s Magnetic Field Reversals: The consensus that Earth’s magnetic field reversed reversely changed due to geological records like magnetic anomalies in rocks, which provide evidence of multiple magnetic field reversals throughout history.
29. Earthquake Prediction: Initially, predicting earthquakes was deemed nearly impossible. While there is still no reliable method for forecasting individual earthquakes, accumulating evidence and advances in knowledge have allowed scientists to identify potential seismic hazards and develop probabilistic assessments.
30. Eggs, Human, Making new ones: The prior scientific consensus stated that women are born with a fixed number of eggs that deplete over their lifetime. However, recent research challenged this notion by providing evidence of the existence of stem cells in the ovaries of adult women that can generate new eggs. This discovery overturned the previous consensus and suggests that women have the potential to produce new eggs throughout their reproductive years, giving hope for new avenues of fertility treatments and possibilities for reproductive health.
31. Electric fluid theory: In the 18th century, the scientific consensus held that electricity operated through the flow of a fluid called electric fluid. This view was challenged by Alessandro Volta’s invention of the battery, which demonstrated that electricity involved the movement of electrons.
32. Embryonic stem cell potential: Initially controversial, the idea that embryonic stem cells had the potential to become a variety of other cell types had to overcome objections.
33. Evolution by natural selection: Charles Darwin’s theory faced significant opposition for many years. However, with subsequent discoveries of transitional fossils, genetic evidence, and observations of natural selection in action, the scientific consensus overwhelmingly supports evolution as the explanation for the diversity of life on Earth.
34. Exoplanets, Existence of : Initially disputed, mounting evidence confirmed the existence of planets beyond our solar system.
35. Extinction of Dinosaurs, Asteroid Cause: The scientific consensus leaned towards gradual climate changes leading to the extinction of dinosaurs, but the discovery of a huge asteroid impact crater in Chicxulub, Mexico, provided strong evidence for a catastrophic event causing their demise.
36. General relativity: Einstein’s theory of general relativity revolutionized our understanding of gravity by providing a more accurate description than Newton’s theory. Evidence came through the observation of light bending around massive objects during a solar eclipse and the subsequent confirmation of gravitational waves.
37. Geocentricity of diseases: In ancient Greece, there was a consensus that diseases were caused by an imbalance of the four humors within the body. This view prevailed until the discovery of microorganisms by scientists like Louis Pasteur, leading to the acceptance of germ theory as the primary cause of diseases.
38. Germ theory of disease: Ignaz Semmelweis’s proposal that handwashing reduces infections was initially dismissed. The consensus used to be that diseases were caused by miasma or bad air. This changed with the work of scientists like Louis Pasteur and Robert Koch, who provided evidence others reproduced that diseases are caused by microorganisms.
39. Heliocentrism: Nicolaus Copernicus’ model placing the Sun at the center of the solar system faced opposition for years. For centuries, hundreds of years, the scientific consensus was that the Earth was the center of the universe. However, evidence from observations made by Galileo Galilei and later Johannes Kepler challenged this notion, ultimately leading to the acceptance of heliocentrism.
40. Helium’s existence: Early skepticism surrounded the discovery of this noble gas.
41. HIV as the cause of AIDS: The initial skepticism surrounding HIV as the cause of AIDS was overturned when virologists discovered the specific HIV antibodies in patients and demonstrated the virus’s ability to destroy immune cells.
42. Hollow Earth theory: In the 17th century, some scientists believed that the Earth was hollow. As evidence from geology and seismology emerged, proving the Earth’s internal structure, the consensus shifted away from the Hollow Earth theory.
43. Homosexuality not being a mental disorder: Despite resistance, scientific consensus has changed over time.
44. Human Evolution: The accepted view of human evolution was challenged by the discovery of Australopithecus africanus by Raymond Dart in the 1920s, providing evidence of a hominin ancestor that didn’t fit the previous consensus.
45. Human Genetic Variation and Race: The earlier consensus that human populations could be classified into distinct races based on genetic differences was overturned with the discovery that genetic variations within populations are much greater than between them.
46. Human Genome Project: There was initial skepticism regarding the feasibility and usefulness of mapping the human genome.
47. Human migration out of Africa: The scientific consensus once suggested that early humans migrated out of Africa only once in a single wave. However, genetic studies indicating multiple waves of migration, along with fossil and archaeological findings, have challenged this consensus, providing more nuanced understanding of human dispersal.
48. Ice Ages: Before the 19th century, the scientific consensus rejected the idea of past ice ages. The discovery of glacial evidence, such as erratic boulders and polished bedrock, led to the acceptance of multiple ice ages in Earth’s history.
49. Indigenous medicinal knowledge: Traditional Indigenous medicinal practices were often dismissed by the scientific establishment. However, accumulating evidence showcasing the efficacy of various plant-based remedies has changed the scientific consensus regarding their medicinal properties.
50. Inheritance of acquired characteristics: Jean-Baptiste Lamarck’s theory was controversial and rejected for many years.
51. Lamarckian Inheritance: Jean-Baptiste Lamarck proposed the theory of inheritance of acquired traits, suggesting that characteristics acquired during an organism’s lifetime could be passed on to subsequent generations. Gregor Mendel’s work on genetics and inheritance, later developed into the modern understanding of DNA and genes, contradicted the Lamarckian concept.
52. Lead poisoning: Initially, lead was widely used in numerous products without acknowledging its toxicity. With accumulating evidence on lead’s harmful effects, especially on children’s development, the consensus shifted towards recognizing the dangers of lead exposure.
53. Lead toxicity in low levels: The scientific consensus held that low levels of lead exposure were not harmful. However, accumulating evidence linked even low levels of lead to various health problems, resulting in widespread support for stricter regulations.
54. Luminal velocity limit: Early skepticism surrounded the notion of nothing traveling faster than light.
55. Luminiferous Aether: The scientific consensus once held that the universe was filled with an undetectable substance called the luminiferous aether, which was thought to be the medium through which light traveled. The Michelson-Morley experiment in 1887 failed to detect the expected motion of Earth through the aether, leading to the abandonment of this concept.
56. Mass extinction events: In the mid-20th century, the theory of uniformitarianism dominated, suggesting that evolution occurred gradually and without major disruptions. This consensus shifted with the discovery of mass extinction events, such as the one that wiped out the dinosaurs, which supported the theory of punctuated equilibrium.
57. Male-only Genetic Inheritance: The consensus that genetic material alone determines offspring characteristics was overturned with the discovery of epigenetic marks in sperm DNA that can affect offspring health.
58. Memories can be altered: The concept initially faced resistance, but later research supported it.
59. Mental illnesses as biological disorders: Historically, mental illnesses were often attributed to personal failures or moral weakness. The understanding that mental disorders have biological underpinnings gained credibility through advancements in neuroscience, genetics, and brain imaging techniques.
60. Miasma Theory: During the 19th century, the miasma theory of disease held that foul odors or “bad air” caused illnesses such as cholera and malaria. The development of the germ theory of disease, supported by the work of Louis Pasteur, demonstrated the role of microorganisms in causing diseases, leading to the dismissal of the miasma theory.
61. Mitochondrial DNA: The idea that mitochondria have separate DNA from the cell nucleus was initially not widely embraced.
62. Nanobacteria: The existence of nanobacteria initially faced skepticism. The prior scientific consensus that nanobacteria did not exist was overturned by the discovery of calcified structures in human and animal tissues, which resembled the characteristics of nanobacteria. Furthermore, research demonstrated that these structures could replicate and form colonies under certain conditions, providing evidence of their living nature. Additionally, genetic analysis revealed DNA sequences related to nanobacteria, supporting the existence of these microorganisms.
63. Nanoparticles’ existence in the atmosphere: Initially, it was believed that the smallest particle size in the atmosphere was around 0.1 micrometers. However, with advancements in technology and improved detection methods, scientists found evidence of nanoparticles with sizes smaller than 0.1 micrometers. This discovery challenged the prior scientific consensus and established the presence of smaller particles in the atmosphere, known as nanoparticles.
64. Nature vs. nurture: Historically, there was a strong scientific consensus that human traits were primarily determined by genetic factors (nature). However, new evidence emerging from twin and adoption studies has led to a greater understanding of the complex interplay between genetic and environmental factors, both nature and nurture.
65. Neanderthal Behavior and Intelligence: The prevailing view of Neanderthals as unintelligent and non-artistic was overturned by discoveries of their sophisticated tool use, artistic capabilities, and the interbreeding with modern humans, suggesting they possessed similar cognitive abilities.
66. Neanderthal interbreeding: Early theories postulated that Neanderthals did not interbreed with modern humans. Advances in ancient DNA sequencing provided evidence of interbreeding, indicating that Neanderthals and early Homo sapiens share genetic ancestry.
67. Neonicotinoid pesticides and bee decline: Initially, the negative impact of neonicotinoid pesticides on bee populations faced resistance and industry denial. Accumulating, independent research provided conclusive evidence of their adverse effects on bees, leading to the scientific consensus embracing concerns over their use.
68. Ocean Acidification, Link to human activities: Ocean acidification, caused by the absorption of excess carbon dioxide by seawater, initially received minimal attention. However, scientific studies on carbon cycle dynamics, aquatic chemistry, and marine organisms provided evidence of ocean acidification, leading to a shift in consensus.
69. Ozone depletion, due to human-made chemicals: Initially, there was skepticism around the theory that human-made chemicals were causing ozone depletion in the Earth’s atmosphere. As evidence from atmospheric measurements and laboratory experiments accumulated, the scientific consensus confirmed the harmful effects of ozone-depleting substances.
70. Particle-wave duality: Classical physics held that particles and waves were separate entities. However, quantum physics introduced the concept of particle-wave duality, which was supported through experimentation, such as the double-slit experiment, where particles exhibit wave-like behavior.
71. Phlogiston Theory: Until the late 18th century, the phlogiston theory explained combustion as a process involving the release of a hypothetical substance called phlogiston. The discovery of oxygen and its role in combustion by Antoine Lavoisier overturned this consensus.
72. Phrenology: Phrenology, the study of personality traits based on the shape of one’s skull, was widely accepted in the 19th century. However, advancements in neuroscience and the discovery of localized brain functions discredited phrenology.
73. Plate tectonic mountain formation: The idea faced skepticism before it became widely accepted.
74. Plate tectonics: Initially met with skepticism, it took time for Alfred Wegener’s theory to gain widespread acceptance. Initially, the majority of geologists rejected the theory, however, with the discovery of new evidence, such as magnetic striping on the seafloor, matching fossils, paleoclimatic data and the movement of continents, the consensus shifted, accepting the theory that Earth’s lithosphere is composed of moving plates.
75. Plate Tectonics on Mars: The consensus that Mars lacked active tectonic plates was overturned with the discovery of evidence like fault lines and volcanic activity on the planet’s surface.
76. Platelet activation in heart disease: It was previously believed that platelet aggregation played a central role in the development of heart disease. However, recent scientific findings have highlighted the importance of inflammation and immune response, shifting the focus away from solely targeting platelet activation in preventive measures.
77. Pluto’s Planetary Status: The consensus that Pluto was the ninth planet was overturned in 2006 by the International Astronomical Union, redefining the criteria for planets and reclassifying Pluto as a “dwarf planet.”
78. Primordial soup theory: The hypothesis of life’s origin faced skepticism before deeper research. The prior scientific consensus was based on the assumption that the Earth’s early atmosphere lacked the necessary conditions to generate organic molecules. However, in the 1950s, Stanley Miller and Harold Urey conducted an experiment that simulated the conditions of the Earth’s early atmosphere and successfully produced amino acids, the building blocks of life. This experiment demonstrated that organic compounds could indeed be formed under the conditions believed to be present when life originated.
79. Punctuated Equilibrium: The concept of gradual evolution was predominant until Stephen Jay Gould and Niles Eldredge introduced the theory of punctuated equilibrium in 1972. It proposed that species evolve in short, rapid bursts followed by long periods of stasis, challenging the prevailing gradualist view.
80. Quantum mechanics: Discovered in the early 20th century, the concept initially faced resistance due to its unconventional nature. Experimental evidence, including the observation of wave-particle duality and the quantized behavior of energy levels, supported this paradigm shift.
81. Secondhand smoke danger: The adverse health effects of smoking were initially acknowledged, but it took time for the scientific consensus to recognize the harmful consequences of secondhand smoke. Epidemiological studies provided evidence of increased risks, leading to a shift in consensus.
82. Smoking and lung cancer: Initially, the scientific consensus on smoking and lung cancer was mixed, with some studies suggesting a weak relationship. As more robust evidence emerged, including epidemiological studies, biochemical evidence, and smoking-related health issues, the scientific consensus shifted towards recognizing the strong link between smoking and lung cancer.
83. Space weather’s influence on Earth: Initially, the idea that solar activity could have significant effects on Earth’s climate and technology was met with skepticism. However, evidence from studying solar cycles, geomagnetic storms, and satellite data led to a consensus acknowledging the impact of space weather on our planet.
84. Spontaneous Generation: The belief in spontaneous generation, the idea that living organisms can arise from non-living matter, was prevalent until the 19th century. Louis Pasteur’s experiments in the 1860s, demonstrating the role of microorganisms in fermentation and debunking spontaneous generation, changed the consensus, demonstrating that life only arises from preexisting life.
85. Subatomic particles’ existence: The prior scientific consensus that subatomic particles did not exist was overturned by several lines of evidence. First, studies by J.J. Thomson and Ernest Rutherford in the late 19th and early 20th centuries provided evidence for the existence of electrons and the atomic nucleus, respectively. Additionally, experiments like the cloud chamber and bubble chamber in the mid-20th century provided visual evidence of particle tracks produced by subatomic particles in high-energy collisions, solidifying their existence.
86. Sugar, Link between consumption and obesity: Initially, the scientific consensus considered dietary fat as the primary cause of obesity, neglecting the role of sugar consumption. Increasing evidence from epidemiological studies and clinical trials led to a shift in consensus, recognizing the contribution of excessive sugar intake to the obesity epidemic.
87. Sun, true nature of: Once believed to be a perfectly smooth and featureless object, advancements in telescopes and solar observations revealed sunspots, solar flares, and other phenomena that altered the scientific consensus about the sun’s nature.
88. Superconductivity: In 1911, Heike Kamerlingh Onnes observed that certain materials, when cooled to extremely low temperatures, displayed zero electrical resistance. This discovery provided concrete evidence for the existence of superconductivity, challenging the prior belief that all materials exhibited some level of electrical resistance at all temperatures.
89. Superfluidity: The evidence that overturned the prior Scientific Consensus on the non-existence of Superfluidity came from experiments conducted at extremely low temperatures. In these experiments, researchers observed unexpected phenomena such as the disappearance of viscosity in helium-4 and helium-3, which contradicted the established theory at the time. The discovery of quantized vortices and other properties demonstrated the existence of superfluidity, leading to a paradigm shift in our understanding of how matter can behave at such extreme conditions.
90. Twins, Identical, Have genetic differences: Evidence of small genetic differences in identical twins has been observed in the form of somatic mutations, which are genetic alterations that occur after conception. These mutations can result in variations in the DNA sequence of cells in each twin’s body. Additionally, differences in gene expression patterns and epigenetic modifications have also been observed, showcasing variations in how genes are regulated in identical twins.
91. Ulcers caused by bacteria: Barry Marshall and Robin Warren faced skepticism when they proposed the bacterial cause of ulcers. Helicobacter pylori causes stomach ulcers, but the discovery initially faced significant resistance by people who had been blaming “stress”. The discovery of Helicobacter pylori and subsequent experiments, overturned the consensus and confirmed the bacterial link to peptic ulcers.
92. Universe, Expansion of: Skepticism existed before evidence of the universe’s expansion became overwhelming. Evidence such as the observation of distant galaxies moving away from us, the measurement of cosmic background radiation, and the detection of redshift in their spectra provided strong indications of an expanding universe, eventually leading to the overturning of the static universe idea.
93. Universe, Accelerating Rate of Expansion of: The prevailing consensus believed that the universe’s expansion was slowing down; however, the discovery of dark energy and observations of distant supernovae led to the paradigm shift of an accelerating expansion.
94. Viruses, Existence of: The existence of viruses was initially controversial due to their small size and inability to be observed by light microscopes. However, groundbreaking experiments carried out by German scientist Adolf Mayer in the late 19th century demonstrated that a disease affecting tobacco plants could be transmitted through a filter that retained bacteria but allowed the smaller agents to pass. Following Mayer’s work, the invention of the electron microscope in the 1930s further confirmed the existence of viruses by allowing their visualization and study, culminating in the acceptance of viruses as distinct entities in the scientific community.
95. Wave-particle duality: The scientific consensus for many years was that light and matter behaved either as waves or particles, but not both. This view changed with the advent of quantum mechanics and the double-slit experiment, which showed that light and matter exhibited characteristics of both waves and particles.

Did you learn anything new from this?