20 Old Beliefs About the World We Now Know Are Totally Wrong

Written By Lisa Marley

Many people in the world used to believe something so firmly, only to find out later it was totally wrong. Throughout history, we’ve held some pretty wild beliefs about our world. Let’s dive into 20 old misconceptions that science has since debunked.

The Flat Earth Theory

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According to the BBC, “Astronomers have known that Earth is a globe for thousands of years,” but that didn’t stop people for centuries from believing that the earth was flat. Sailors feared they’d fall off the edge if they ventured too far, but we now know our planet is a round sphere.

The Geocentric Model

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Ancient civilizations believed Earth was the center of the universe, with the sun, moon, and stars revolving around it. This belief persisted until Copernicus and Galileo provided evidence for the heliocentric model, showing that Earth orbits the sun, forever changing our understanding of the cosmos.

Spontaneous Generation

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People once thought living organisms could spontaneously arise from non-living matter, like maggots from meat. This idea was debunked by Louis Pasteur, who demonstrated that life comes from existing life, laying the groundwork for modern microbiology and a better understanding of disease prevention.

The Four Humors

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The balance of four bodily fluids—blood, phlegm, black bile, and yellow bile—was what Ancient Greek medicine was based on. Imbalances were thought to cause illness, but modern medicine has since shown that diseases are caused by pathogens, genetics, and environmental factors, not imbalances of mythical humors.

Phrenology

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In the 19th century, phrenologists believed the bumps on a person’s skull could reveal their personality traits and intelligence. This pseudoscience has been thoroughly discredited by modern neuroscience, which shows that our brains are far more complex and not easily read from the outside.

The Earth Is Only a Few Thousand Years Old

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Many cultures believed the earth was only a few thousand years old, based on religious texts. However, advances in geology and radiometric dating have revealed that our planet is approximately 4.5 billion years old, giving us a much deeper understanding of Earth’s history and development.

The Indivisible Atom

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Early atomic theory suggested that atoms were the smallest indivisible particles of matter. However, the discovery of subatomic particles like protons, neutrons, and electrons, as well as the development of quantum mechanics, revealed a much more intricate and fascinating world within the atom.

Bloodletting as a Cure-All

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For centuries, doctors practiced bloodletting to treat various ailments, believing it balanced bodily fluids, but this dangerous practice was finally abandoned in favor of more effective treatments. And as medical science progressed, we learned about the true causes of diseases and proper medical care.

Humans Are the Only Tool Users

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It was once believed that humans were the only species capable of using tools. Observations of animals like chimpanzees, dolphins, and even birds using tools to solve problems and access food have proven that tool use is more widespread in the animal kingdom than previously thought.

The Superiority of Human Senses

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People used to think that human senses were superior to those of animals. However, research has shown that many animals possess senses far beyond our capabilities. For example, dogs have an extraordinary sense of smell, and some birds can see ultraviolet light, revealing a richer sensory world.

The Existence of Ether

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Scientists once invested in a substance called ether, which they thought filled all space and was the medium through which light traveled. The experiment and Einstein’s theory of relativity disproved this notion, showing that light can travel through the vacuum of space without any medium.

The Universe Is Static and Unchanging

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Before the discovery of the expanding universe, it was widely believed that the cosmos were static and eternal. Edwin Hubble’s observations revealed that galaxies are moving away from each other, leading to the Big Bang theory and a dynamic view of the universe’s origin and evolution.

Life Exists Only on Earth

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The belief that Earth is the only planet with life has been challenged by the discovery of extremophiles, organisms that thrive in extreme conditions. This has opened the possibility of life existing in other parts of our solar system and beyond, expanding our search for extraterrestrial life.

The Immovable Continents

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The idea that continents were fixed in place was prevalent until the theory of plate tectonics emerged, and scientists like Alfred Wegener proposed that continents drift over time, a theory now supported by ample geological evidence, explaining phenomena like earthquakes and the formation of mountains.

Lightning Never Strikes the Same Place Twice

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Many people believe that lightning never strikes the same place twice, but this is a myth. Lightning often strikes the same locations multiple times, especially tall structures like the Empire State Building, which can be hit dozens of times each year, demonstrating the unpredictability of nature.

Humans Have Only Five Senses

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The belief that humans have only five senses—sight, hearing, smell, taste, and touch—is outdated; modern science recognizes additional senses such as balance, temperature, pain, and body position (proprioception), providing a more comprehensive understanding of how we perceive and interact with the world.

The Brain’s Size Determines Intelligence

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It was once thought that brain size was directly correlated with intelligence, which does make sense; however, studies have shown that intelligence is more closely related to the complexity and connectivity of neural networks rather than sheer brain volume. This debunks simplistic views of brain functionality.

Diamonds Are Rare

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While diamonds are marketed as rare and valuable gemstones, they are actually quite abundant in nature. The perception of rarity has been carefully cultivated by the diamond industry to maintain high prices. In reality, other gemstones like sapphires and emeralds are much rarer.

We Use Only 10% of Our Brains

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The myth that humans use only 10% of their brains has been widely proven false by neuroscientists, as brain imaging technology shows that we use all parts of our brains, even while at rest. This misconception underestimates the brain’s incredible complexity and functionality.

Different Parts of the Tongue Detect Different Tastes

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The tongue map, which suggests that different areas of the tongue are responsible for detecting specific tastes (sweet, sour, salty, bitter), is incorrect. All taste buds can detect all five basic tastes, including umami. This understanding helps us appreciate the full range of our gustatory experiences.

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