Uploaded October 2025 | Updated September 2026, 2 weeks ago
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REFERENCE VIDEOS
How General Relativity works youtu.be/tzQC3uYL67U
Newton, the Greatest Scientist who ever lived youtu.be/MApnf7L4g44
Quantum ElectroDynamics (QED) youtu.be/PutOOpAkjQ4
All Physics Explained in 15 mins youtu.be/TTHazQeM8v8
CHAPTERS
0:00 Science is littered with bad theories
0:56 Aristotle's mechanics was really bad
2:25 The crazy heat "fluid" theory, Caloric
5:53 The Luminiferous Aether
7:53 Newton's failure: Corpuscular light
9:48 Newton's law of universal gravitation
12:05 How to spot when a theory is BAD
SUMMARY
Science is full of once-brilliant ideas that now seem absurd. They weren’t crazy when proposed—they were the best explanations available. Each was eventually replaced by a theory that explained more phenomena with fewer assumptions. Looking back at five major fallen theories reveals how science self-corrects and refines itself.
For nearly two millennia, Aristotle’s view of motion dominated: objects required a push to keep moving; heavy things fell faster; fire rose to its natural place. The world seemed to confirm this—until Galileo realized that motion continues unless something interferes. Friction, not nature’s “desire for rest,” slows things down. Newton later formalized this in his first law of motion: an object in motion stays in motion unless acted on by a force. By uncovering hidden forces, science learned that nature’s rules are simpler than they appear.
In the 18th century, scientists believed heat was a fluid called caloric that flowed from hot to cold. It explained everyday experiences, but experiments like boring cannon barrels producing endless heat challenged it. James Joule’s paddle-wheel experiments showed that mechanical work could generate heat, proving it wasn’t a substance but energy in motion. The kinetic theory of gases replaced caloric with molecular motion, leading to thermodynamics and the concept of entropy—energy’s natural tendency to spread out. Caloric theory fell because it violated energy conservation, though we still talk about “heat flow” today.
#aether
Nineteenth-century physicists also thought light must travel through a medium—the luminiferous aether. All waves, after all, needed something to ripple through. But the 1887 Michelson-Morley experiment found no difference in light speed regardless of direction, implying no aether wind. Einstein resolved this by asserting two principles: the laws of physics are the same for all observers moving at constant velocity, and the speed of light is constant for all of them. Space and time themselves adjust—lengths contract, clocks slow—removing the need for aether. Special relativity explained more with fewer assumptions. The concept of a universal “field,” however, survived in modern quantum field theory, where light is an excitation of the electromagnetic field filling spacetime.
Even Newton, history’s most influential scientist, wasn’t always right. He pictured light as tiny particles or corpuscles, which explained reflection and refraction but not diffraction or interference. Those patterns showed light behaving like a wave. Yet the photoelectric effect revealed that light also behaves as particles—photons—whose energy depends on frequency, a discovery that earned Einstein his Nobel Prize. Modern quantum electrodynamics unifies both pictures: light is simultaneously wave and particle, depending on how it’s observed.
Newton’s law of gravity—forces acting instantaneously between masses—worked flawlessly for centuries, until Mercury’s orbit deviated slightly from prediction. Einstein’s general relativity solved it by reimagining gravity as the curvature of spacetime itself. The theory explained Mercury’s precession, light bending near the Sun, time dilation, and gravitational waves, all later confirmed. Newton’s law remains a special case of Einstein’s, valid for weak gravity and low speeds.
From Aristotle to caloric, aether, corpuscles, and Newton’s gravity, the same pattern repeats: old theories are absorbed into deeper, more unifying frameworks. Better theories expand scope, increase precision, unify phenomena, and recover what worked before. Science isn’t a fixed book of truths—it’s a constantly revised notebook. The losers weren’t foolish; they were necessary steps toward sharper understanding. Curiosity and skepticism remain the true engines of progress.
Click this link https://boot.dev/?promo=ARVINASH and use my code ARVINASH to get 25% off your first payment for boot.dev
TALK TO ARVIN on PATREON
patreon.com/arvinash
REFERENCE VIDEOS
How General Relativity works youtu.be/tzQC3uYL67U
Newton, the Greatest Scientist who ever lived youtu.be/MApnf7L4g44
Quantum ElectroDynamics (QED) youtu.be/PutOOpAkjQ4
All Physics Explained in 15 mins youtu.be/TTHazQeM8v8
CHAPTERS
0:00 Science is littered with bad theories
0:56 Aristotle's mechanics was really bad
2:25 The crazy heat "fluid" theory, Caloric
5:53 The Luminiferous Aether
7:53 Newton's failure: Corpuscular light
9:48 Newton's law of universal gravitation
12:05 How to spot when a theory is BAD
SUMMARY
Science is full of once-brilliant ideas that now seem absurd. They weren’t crazy when proposed—they were the best explanations available. Each was eventually replaced by a theory that explained more phenomena with fewer assumptions. Looking back at five major fallen theories reveals how science self-corrects and refines itself.
For nearly two millennia, Aristotle’s view of motion dominated: objects required a push to keep moving; heavy things fell faster; fire rose to its natural place. The world seemed to confirm this—until Galileo realized that motion continues unless something interferes. Friction, not nature’s “desire for rest,” slows things down. Newton later formalized this in his first law of motion: an object in motion stays in motion unless acted on by a force. By uncovering hidden forces, science learned that nature’s rules are simpler than they appear.
In the 18th century, scientists believed heat was a fluid called caloric that flowed from hot to cold. It explained everyday experiences, but experiments like boring cannon barrels producing endless heat challenged it. James Joule’s paddle-wheel experiments showed that mechanical work could generate heat, proving it wasn’t a substance but energy in motion. The kinetic theory of gases replaced caloric with molecular motion, leading to thermodynamics and the concept of entropy—energy’s natural tendency to spread out. Caloric theory fell because it violated energy conservation, though we still talk about “heat flow” today.
#aether
Nineteenth-century physicists also thought light must travel through a medium—the luminiferous aether. All waves, after all, needed something to ripple through. But the 1887 Michelson-Morley experiment found no difference in light speed regardless of direction, implying no aether wind. Einstein resolved this by asserting two principles: the laws of physics are the same for all observers moving at constant velocity, and the speed of light is constant for all of them. Space and time themselves adjust—lengths contract, clocks slow—removing the need for aether. Special relativity explained more with fewer assumptions. The concept of a universal “field,” however, survived in modern quantum field theory, where light is an excitation of the electromagnetic field filling spacetime.
Even Newton, history’s most influential scientist, wasn’t always right. He pictured light as tiny particles or corpuscles, which explained reflection and refraction but not diffraction or interference. Those patterns showed light behaving like a wave. Yet the photoelectric effect revealed that light also behaves as particles—photons—whose energy depends on frequency, a discovery that earned Einstein his Nobel Prize. Modern quantum electrodynamics unifies both pictures: light is simultaneously wave and particle, depending on how it’s observed.
Newton’s law of gravity—forces acting instantaneously between masses—worked flawlessly for centuries, until Mercury’s orbit deviated slightly from prediction. Einstein’s general relativity solved it by reimagining gravity as the curvature of spacetime itself. The theory explained Mercury’s precession, light bending near the Sun, time dilation, and gravitational waves, all later confirmed. Newton’s law remains a special case of Einstein’s, valid for weak gravity and low speeds.
From Aristotle to caloric, aether, corpuscles, and Newton’s gravity, the same pattern repeats: old theories are absorbed into deeper, more unifying frameworks. Better theories expand scope, increase precision, unify phenomena, and recover what worked before. Science isn’t a fixed book of truths—it’s a constantly revised notebook. The losers weren’t foolish; they were necessary steps toward sharper understanding. Curiosity and skepticism remain the true engines of progress.
