Three Eureka Moments:

Newton, Einstein, Darwin ‘Got It!’

By Chris Costanzo

A "Eureka Moment" is when you have a sudden insight, a brainwave, an instant comprehension, or an immediate solution to a puzzle. It is named after the Greek philosopher Archimedes in the third century B.C., who solved the problem of calculating the buoyancy of solid bodies immersed in a liquid.

Archimedes was thinking about the matter while taking his evening bath. As he settled into the tub he watched the water rise and felt himself get lighter. Suddenly, like a flash, he understood the fundamental relationship between liquid displacement and buoyancy.

Crazed by his insight, he jumped out of the bathtub and ran stark naked out of his house into the streets of Syracuse (in Sicily), shouting over and over, "I’ve got it! I’ve got it!" while his embarrassed family ran after him with his bathrobe.

"I’ve got it" is "Eureka" in Greek, and thus the term was born.

More recently--within the past 350 years--three great men had their own Eureka Moments, which they developed into scientific theories that utterly transformed our understanding of the universe around us. They were Isaac Newton, Albert Einstein, and Charles Darwin.

Their insights were so simple that the public reaction to them was akin to hitting one’s self on the forehead and saying, "Why of course! That’s it! Why didn’t we think of it before!"

The Apple and the Moon

In Newton’s day, people knew what gravity is. If you let something go, it would fall. But the big question was why didn’t everything fall that wasn’t held up—things like the moon, for example.

The common explanation was that the moon, the planets and the stars are situated in Heaven, and the rules are different up there. But this sounded more like a statement than a rational explanation, so the puzzle continued to gnaw away at many people.

One of these was young Isaac Newton, who was taking a break after having just graduated from Cambridge University in 1665. He was goofing off in his back yard at home when he noticed an apple falling, and he wondered for the umpteenth time why wasn’t the moon falling too? And then it hit him. The moon was falling, just like the apple! Eureka!

As Newton munched the apple, he realized that the reason the moon didn’t hit the earth is that it is also moving sideways as it falls. The earth’s surface is curved, so Newton saw that the moon’s sideways motion brought it over a surface that was constantly receding as the moon was falling. In effect, the moon was falling perpetually around the earth.

Now, the Hard Part

It was one of the greatest insights in the history of science. But insight by itself simply isn’t enough. It was only a hypothesis that had yet to be developed into a theory. To make it into a theory, Newton had to add deductive reasoning, and then bolster it with supporting observations.

And so he did. At that time a plague had spread through Britain. Newton’s university remained closed for a couple of years, so he couldn’t go back for an advanced degree. People stayed in their houses as much as possible.

Rather than be bored out of his mind, Newton developed his insight into theory by using math, geometry, and measurements made by astronomers and physicists.

Newton deduced from his Eureka Moment that any moving object—like the moon—will continue its motion in a straight line through the force of inertia, unless acted on by an outside force. And if acted on by an outside force, like gravity, the object would deviate from a straight line in an amount proportional to that force.

Newton devised a means to calculate such movements, and then confirmed their accuracy through measurements. His calculations also showed that bodies attract each other in direct proportion to their masses, and in inverse proportion to the square of the distance between them—which became known as the law of gravity. Newton’s work became the foundation of modern physics.

Teenaged Boredom

Einstein’s first Eureka Moment occurred around 1895 when he was a bored, lazy, and very indifferent 16-year-old school boy. He daydreamed a lot, and during one of his daydreams, he wondered what a beam of light would look like if he could run past it.

It suddenly occurred to him that the beam of light would look exactly the same, and that neither he nor anything else could ever outrun it. In fact, the light would always appear to be moving at the same speed.

In his flash of insight, young Einstein saw that if, say, a lamp could move towards a person faster than the speed of light, it would overtake its own image, so the person wouldn’t see the lamp until it got to him.

Also, the first images he would see would be the most recent ones when the lamp was close, and the earlier images when it was farther away would reach him later. What he would see, then, is the lamp appearing suddenly in front of him, and moving backwards away from him instead of towards him.

Since Einstein understood that light is the main way to communicate between any two points in the universe, he sensed that the speed of light must never change relative to anything—if not it would be a topsy-turvy world. Eureka!

Like Newton before him, Einstein had to develop his insight into a theory that was both logical and confirmable by observation. He spent the next nine years in school, hating every boring minute of his classes, but acquiring the necessary tools of math and physics that later allowed him to publish his great insight. When he did, he was able to demonstrate that, since light is immutable, time itself must measure differently depending on where one measures it. His discovery revolutionized humanity’s concept of space and time.

Seasick Insight?

Charles Darwin had his Eureka Moment in the 1830s as a seasick young man on a British naval vessel engaged in a five-year scientific expedition around the world. He was the ship’s naturalist, charged with observing, recording, and collecting specimens of flora and fauna all over the globe.

Contrary to what many people think, Darwin did not originate the idea that all species of life came about through evolution. Physical evidence had suggested the idea to many thinkers as early as ancient Greece, and many scientists in Darwin’s day also subscribed to it. But at that time, evolution was merely a hypothesis, not a scientific theory because there was no logical explanation or physical evidence of exactly how the process worked.

Darwin had plenty of leisure while at sea to think about the problem, even though his attention was often diverted due to his strong susceptibility to seasickness. He contemplated the biological specimens that he had collected on land, and he noted their subtle diversity and adaptation to different environments. He also read a recent book, "Principles of Geology," by Charles Lyell, which presented overwhelming evidence that the earth was not a few thousand years old, as many thought, but actually millions upon millions of years old.

And then, possibly while lying seasick on his bunk, Darwin’s Eureka Moment hit him.

Fighting the nausea, he ticked off the elements of his insight. The progeny of all living things are always slightly different from their parents, right? These slight mutations are random, and some are helpful and others detrimental, right?

As the environments change, those whose mutations are beneficial to survival will have a greater chance to survive, to reproduce and to pass their mutations to their offspring, right? Over a very long period there will be many environmental changes resulting in the accumulation of many helpful mutations in surviving creatures, right? And, after a long period, these cumulative mutations will result in creatures profoundly different from their ancestors, thereby accounting for differences among species, right? It was so clear. Eureka!!

That was it in a nutshell. It was Darwin’s simple common-sense discovery of natural selection to explain the workings of biological evolution. After returning to Britain, he spent over 20 years systematically organizing and describing physical evidence to support his insight, thereby transforming the hypothesis of evolution into a theory. Darwin’s discovery has since become the great unifying principle of all the biological sciences.

Theories, to be accepted, must have predictive value.

Ideas That Illuminate

Today, Newtonian mechanics, Einsteinian relativity, and Darwinian evolution, serve not only to explain but to predict countless events in physics and biology.

These three theories stemmed from three Eureka moments that could have occurred to many a thoughtful person willing to take the time and energy to think while unfettered by the prejudices and pressures of earlier beliefs. Newton, Einstein, and Darwin had another quality as well. They were willing to work hard to organize their thoughts and develop their insights logically and convincingly for the benefit of mankind.