Let's take a look at science in 1946
In 1946 science was advancing rapidly in the aftermath of the Second World War, but scientists still held beliefs that would later be overturned by new evidence.
Some ideas were genuinely accepted as scientific facts and later disproven, while others were reasonable theories that scientists eventually refined or abandoned.
Here are some particularly interesting examples, from medicine and biology to astronomy and physics.
20 things science believed in 1946 that we now know were wrong
1. Continents were essentially fixed in place
The belief: The continents and ocean basins were largely permanent features of Earth's surface.
German scientist Alfred Wegener had proposed continental drift decades earlier, arguing that continents had once been joined together. However, many geologists rejected his theory because he couldn't convincingly explain what force moved the continents.
What changed: During the 1950s and 1960s, discoveries about the ocean floor, magnetic striping and seafloor spreading helped establish the theory of plate tectonics.
We now know that Earth's crust is divided into moving plates. The Atlantic Ocean continues to widen in some places, while other plates collide to create mountain ranges.
Why it matters: An idea once dismissed by much of the scientific establishment became fundamental to modern geology.
One qualification: continental drift was not universally rejected in 1946. Some scientists supported it, but the modern mechanism had not yet been established.
2. Peptic ulcers were primarily caused by stress and lifestyle
The belief: Stomach ulcers were generally attributed to stress, excess stomach acid, spicy foods and lifestyle factors.
These factors can influence digestive symptoms, but the underlying causes of many ulcers were not properly understood.
What changed: In 1982, Australian researchers Barry Marshall and Robin Warren identified the importance of Helicobacter pylori, a bacterium associated with gastritis and peptic ulcers.
Antibiotic treatment can eradicate the infection and cure many ulcers.
Marshall and Warren received the 2005 Nobel Prize in Physiology or Medicine.
The lesson: A medical condition commonly attributed to someone's behaviour can have an underlying biological cause.
Stress and certain medications can still contribute to ulcer problems, so the discovery did not make every earlier explanation irrelevant.
3. The brain could not generate new neurons in adulthood
The belief: The adult human brain was generally considered incapable of producing new neurons.
Scientists knew that the brain could change through learning and experience, but the extent of its ability to generate new nerve cells remained controversial.
What changed: Research later established adult neurogenesis in certain regions of the brains of several mammals. Evidence for adult neurogenesis in humans has also emerged, although its extent in adulthood remains debated.
We now understand that the brain has greater capacity for adaptation than the older, rigid model suggested.
Important distinction: The brain does not routinely replace all its neurons. Most neurons are long-lived, and the extent of new-neuron production in the adult human brain is still an active research question.
4. The universe might be static and eternal
The belief: The universe's origin and ultimate history were unresolved, and some scientists favoured models in which it was eternal or essentially unchanging.
By 1946, however, the idea of an expanding universe was already established in important scientific circles. Edwin Hubble's observations had helped demonstrate cosmic expansion, and Georges Lemaître had proposed an early-universe origin model.
The steady-state theory, which described an eternally expanding universe without a beginning, came later, in 1948.
What changed: In 1965, the discovery of the cosmic microwave background provided powerful evidence for the hot Big Bang model.
Today, the evidence strongly supports a universe that evolved from an extremely hot, dense early state approximately 13.8 billion years ago.
The fascinating part: The Big Bang wasn't a discovery that scientists made out of nowhere. It emerged through a long dispute between competing interpretations of astronomical evidence.
We still do not know with certainty what, if anything, preceded the earliest phase we can currently describe.
5. The continents and Earth's geological features were far older than some estimates allowed
The belief: The age of Earth had been disputed for centuries. By 1946, however, most geologists accepted that Earth was enormously old, even though its precise age remained uncertain.
Some earlier estimates had placed Earth's age at only tens of millions of years.
What changed: Improvements in radiometric dating allowed scientists to calculate ages using radioactive decay.
By the mid-20th century, scientists were closing in on the modern estimate of approximately 4.54 billion years.
The lesson: Scientific estimates can change dramatically when researchers discover a reliable way to measure something that previously could only be inferred indirectly.
This wasn't a case where scientists in 1946 universally believed Earth was young. They already knew it was ancient.
6. The stomach was too acidic for bacteria to survive
The belief: The stomach's highly acidic environment was long considered a powerful barrier to bacterial survival.
Although scientists knew that some microorganisms could survive harsh conditions, the idea that a bacterium could colonise the human stomach and contribute to disease was not widely accepted.
What changed: The discovery of Helicobacter pylori demonstrated that certain bacteria can survive in the stomach's mucus layer and contribute to inflammation and ulcers.
The bacterium uses the enzyme urease to help it cope with its acidic surroundings.
This discovery fundamentally changed the understanding of stomach disease.
It also illustrates an important principle: an environment that is hostile to most organisms may still support specialised life.
7. Viruses were poorly understood and sometimes confused with other infectious agents
The belief: Viruses had already been identified by 1946, but scientists still lacked the detailed molecular understanding of how they function.
The structure of viruses, their replication mechanisms and their relationships with host cells remained incompletely understood.
What changed: Advances in electron microscopy, molecular biology and genetics revealed how viruses carry genetic information and use host-cell machinery to reproduce.
The discovery of DNA's double-helical structure in 1953 was one milestone in the wider revolution in molecular biology.
A crucial distinction: It would be incorrect to say scientists in 1946 did not believe viruses existed. They absolutely did. The later advances transformed understanding rather than disproving the basic concept.
8. Smoking was not yet universally recognised as a major cause of lung cancer
The belief: Some doctors and researchers had already raised concerns about smoking and lung cancer, but the strength of the evidence and its implications were not yet widely accepted.
Cigarette smoking was common, socially fashionable and heavily advertised.
What changed: Large epidemiological studies, including landmark research published in the 1950s, strengthened the evidence linking smoking to lung cancer. Subsequent research established smoking as a cause of several cancers and numerous other diseases.
The 1964 US Surgeon General's report became a landmark in communicating the evidence.
The lesson: A dangerous practice can remain culturally normal long after warning signs have appeared.
This was not a belief unanimously held by scientists in 1946; the evidence was developing, and some researchers already suspected the connection.
9. The genetic material responsible for heredity was not conclusively established
The belief: Scientists knew that chromosomes contained DNA and proteins, but the precise role of DNA in heredity remained controversial.
Many researchers considered proteins strong candidates because of their chemical complexity.
What changed: Experiments by Oswald Avery and colleagues in 1944 provided compelling evidence that DNA was the substance responsible for transforming bacterial characteristics.
The Hershey–Chase experiment in 1952 provided further influential evidence that DNA, rather than protein, carried the genetic instructions in the viruses they studied.
The discovery of DNA's double-helical structure followed in 1953.
The important detail: Scientists had not universally established that proteins carried hereditary information in 1946. The evidence was already shifting toward DNA.
This is a particularly good example of a scientific revolution occurring through successive experiments rather than one sudden revelation.
10. Neanderthals were often portrayed as brutish, primitive ancestors
The belief: Popular and sometimes scientific depictions portrayed Neanderthals as stooped, unintelligent, brutish creatures occupying a simple evolutionary position below modern humans.
Some of these portrayals reflected the limited evidence available; others were distorted by assumptions about what human evolution was supposed to look like.
What changed: Archaeological discoveries, improved reconstructions and genetic research revealed a more complex picture.
Neanderthals:
- Made sophisticated stone tools
- Hunted large animals
- Adapted to difficult environments
- Interbred with modern humans
- Contributed DNA to many present-day populations outside sub-Saharan Africa
The lesson: Evolution is not a simple ladder in which one species inevitably progresses into another. Human evolution was a branching process involving multiple populations.
Neanderthals were not simply modern humans' direct ancestors, nor were they the stupid caricatures once depicted.
11. The brain's two hemispheres were often described too simplistically
The belief: Ideas about the brain's left and right hemispheres were already developing, but their functions were not well understood.
Over subsequent decades, popular accounts increasingly portrayed the left hemisphere as logical and mathematical, and the right as creative and artistic.
What changed: Modern neuroscience established that the hemispheres do have specialised functions, but that most complex activities depend on networks spanning both sides of the brain.
Language is often strongly left-lateralised, for example, but creativity is not simply a right-brain activity.
The lesson: A genuine scientific finding can become distorted when reduced to an overly simple public explanation.
This is a case of correcting an oversimplification rather than overturning a firmly established scientific fact.
12. The origin of infectious diseases was not always correctly understood
The belief: By 1946, germ theory was well established. Scientists understood that many diseases were caused by microorganisms, and antibiotics had begun transforming medicine.
However, many individual diseases still had uncertain or incorrect explanations.
What changed: Later research identified previously unknown pathogens, clarified transmission routes and corrected mistaken assumptions.
Examples include:
The identification of HIV as the cause of AIDS in the 1980s.
The discovery of Helicobacter pylori's role in many stomach ulcers.
The identification of prions as infectious agents responsible for certain neurodegenerative diseases. Prions were particularly surprising because they are infectious proteins rather than conventional organisms containing DNA or RNA.
The lesson: Establishing a broad principle does not mean scientists have correctly identified every instance in which it applies.
13. There were limits to what humans could observe in the universe
The belief: In 1946, astronomers already knew that the Milky Way was only one galaxy among many. Edwin Hubble had helped establish this decades earlier.
However, the observable universe remained far less thoroughly mapped than it is today.
What changed: Radio astronomy, space telescopes, improved detectors and advanced computing transformed our ability to study distant galaxies, black holes, exoplanets and the early universe.
Scientists have since discovered thousands of confirmed exoplanets, revealing that planets are common around other stars.
The lesson: Sometimes science doesn't overturn a theory; it reveals that reality is vastly more extensive and complicated than previously observed.
14. Nuclear energy was not understood in all its long-term environmental consequences
The belief: By 1946, nuclear fission was established science. Scientists understood that nuclear reactions could release enormous amounts of energy.
But the long-term consequences of nuclear technology, radioactive waste management and large-scale nuclear accidents were not yet fully understood.
What changed: Decades of experience and research revealed more about radiation exposure, contamination pathways, radioactive waste and the environmental consequences of nuclear accidents.
Events such as Chernobyl and Fukushima provided evidence about the risks associated with different reactor designs, emergency responses and failures of safety systems.
An important qualification: Scientists in 1946 were not unaware of radiation's dangers. The Manhattan Project had already demonstrated how seriously radiation hazards needed to be treated. The later developments expanded knowledge of long-term risks rather than disproving nuclear physics.
15. Human intelligence and behaviour were often explained through overly simplistic biological theories
The belief: Early and mid-20th-century research sometimes attributed differences in intelligence, personality and behaviour to simplistic theories of heredity or rigid biological categories.
Some claims were influenced by eugenics, racial prejudice and inadequate research methods.
What changed: Advances in genetics, psychology, statistics and neuroscience demonstrated that human traits are shaped by complex interactions between genes, development, environment and experience.
Modern genetics has also shown that simplistic racial classifications do not accurately represent the complexity of human genetic variation.
The lesson: Scientific language does not automatically make a claim scientifically sound. Assumptions, social prejudices and poor methods can influence research, even when presented as objective science.
Five more surprising examples
There are several other cases worth mentioning, although they are not all examples of beliefs universally held in 1946.
Earlier belief or assumption | What later evidence showed
16. All matter was composed of indivisible atoms in the most literal sense.
Atoms contain electrons and nuclei; nuclei contain protons and neutrons, which themselves have internal structure.
17. The human appendix had no meaningful biological function.
Research suggests it has immune functions and may help preserve beneficial gut bacteria, although it is not essential for survival.
18. Adult human bones were essentially inert structures.
Bone is living tissue that continuously remodels itself.
19. The number of chromosomes in a human cell was thought to be 48.
The chromosome example is particularly interesting: for years, the accepted number was 48, partly because the available microscopy and preparation methods made accurate counting difficult.
In 1956, Joe Hin Tjio and Albert Levan established that the normal human chromosome number is 46.
20. The surface of Venus might support a relatively Earth-like environment.
Spacecraft observations revealed an extremely hot surface and crushing atmospheric pressure.
So what does this tell us about science?
There is a deeper point here. Science is often portrayed as a steadily accumulating collection of facts. In reality, its history is more complicated.
Scientific understanding advances through several processes:
- Observation: Scientists notice something that needs explaining
- Hypothesis: They develop a proposed explanation
- Testing: Experiments and observations assess whether it fits the evidence
- Revision: New findings may require an explanation to be modified or abandoned
- Convergence: Independent evidence from different methods can establish a much stronger consensus
There is an important caveat: the fact that science has been wrong before does not necessarily mean today's scientific consensus is likely to be wrong about everything.
Some scientific conclusions are exceptionally well supported. Others do remain uncertain though, particularly when evidence is incomplete or difficult to interpret.
An interesting question: What do we believe today that might be wrong in 2046?
If we apply the same historical perspective to modern science, several areas stand out as candidates for significant revision:
Consciousness: We still lack a complete explanation of how subjective experience arises from brain activity.
Dark matter: We have strong evidence for gravitational effects that ordinary visible matter cannot explain, but the nature of dark matter remains unknown.
Dark energy: The accelerated expansion of the universe is well supported, but its underlying explanation remains uncertain.
The origins of life: We do not yet have a complete account of how life first emerged from non-living chemistry on Earth.
The human microbiome: We are still learning how microorganisms living in and on our bodies affect health, disease and development.
The limits of artificial intelligence: We do not yet fully understand the capabilities, limitations or internal representations of increasingly complex AI systems.
The real lesson may be this: the most dangerous scientific error is not necessarily having an incorrect theory. It is becoming so confident in a theory that we stop looking for evidence that might prove it wrong.
Read more on:
Lip, Dip, Paint: The Radium Girls
Eben Byers: The Tragic Radithor Story
The 10 Most Radioactive Places on Earth: Hidden Hotspots Where Science, History, and Danger Collide
Comments
Post a Comment