The Copernican Revolution

– An Open & Optimistic Theory of Knowledge  –

The Dark Ages was marked by an authoritative and pessimistic theory of knowledge. The Catholic Church, largely under the spell of Plato, held a monopoly on truth, which stripped people of their freedom to pursue truth and understanding for themselves. The Bible was considered perfect and in no need of improvement. So, there was no need for progress, and in fact was no real progress throughout the Dark Ages, just strict adherence to the dogma.

But after the fall of Constantinople in 1453, when scholars migrated to Italy with what ancient writings had survived, an optimism caught flame in Italy as people began to rediscover ancient Greek philosophers like Protagoras. Reason had once again fertilized the growth of art, poetry, and innovation, as it did in Ancient Greece. People like Michelangelo, Shakespeare, and Leonardo Da Vinci seemed to have woken up every day like kids on Christmas, ecstatic to see what the Space of Possibility had in store for them next.

In cosmology, however, the rebirth of ancient Greek philosophy stirred up quite the conflict. You see, most people throughout history believed the earth sits at the center of the cosmos. And of course they did. Just look for yourself — the sun, moon, and stars seem to rotate around us. Plus, I don’t feel the earth moving. Do you? In any case, this wasn’t an open question for Christians. The Bible is clear: the sun stopped its rotation around the earth and stood still over Gibeon. (Joshua 10:12). So, there wasn’t much room for debate on the matter. The holy scriptures said so and that was that.

The Copernican Revolution

Enter Nicolaus Copernicus (1473–1543), an ecclesiastic astronomer who thought holy scripture had it all wrong. It’s not the earth, he argued, but the sun that sits at the center of the cosmos. Why? No, not because of some cool new observation. Copernicus’ great ‘insight’ was actually inspired by Plato’s writings. Plato tells us that the sun, because it gives us light, is of the highest order in the material realm (which he contrasted to the immaterial realm of forms). So, Copernicus thought the sun, not the earth, should sit at the center of the universe.

All the hype and legacy for this so-called ‘insight’?! Yeah, I know. But the consequences of this ‘insight’ are hard to exaggerate, as you’ll see shortly.

Because Copernicus knew the Catholic Church would punish him for even considering such a heresy, he didn’t make his idea public. Instead, he asked a friend to publish the idea after Copernicus died. Plus, it wasn’t just the Church Copernicus had to worry about. The reformers wouldn’t accept his heliocentric model either. Martin Luther, for example, after its publication said, “People give ear to an upstart astrologer who strove to show that the earth revolves, not the heavens…sun and the moon…. This fool wishes to reverse the entire science of astronomy; but sacred Scripture tells us that Joshua commanded the sun to stand still, and not the earth.” (The Table Talk of Martin Luther)

In any case, a few years after its publication, leaders of the Catholic Church met up in the Italian city of Trent to figure out how to curb the German princes and reformers who had started to challenge the Vatican’s authority. The Council of Trent ended up issuing decrees covering every aspect of Church authority. It published the Index of Forbidden Books, which named 583 heretical texts, including Copernicus’s On the Revolutions of the Celestial Spheres. It formed a band of militant missionaries called the Jesuits. And it reestablished the Roman Inquisition to torture heretics until they restored their faith.

Giordano Bruno

There was one man, however, who refused to abandon his own heart. Giordano Bruno (1548–1600), one of history’s most courageous defenders of free-thought, dared to read the books that had been banned by the Church. And in one of them, he stumbled across a thought experiment by the ancient philosopher Lucretius, who asked his readers to imagine standing at the edge of the universe and shooting an arrow outward. If the arrow keeps going, space must be infinite, Lucretius argued. And if, on the other hand, the arrow hits a wall, then that wall must lie beyond what you thought was the edge. Now, if you stand on that wall and shoot another arrow, the same two possibilities remain. Either way, it seemed to Lucretius as if the universe was infinite.

Shaky reasoning, no doubt. But in any case, Bruno ran with this idea. Still a deeply religious man, like everyone else at the time, Bruno thought that his god must be infinite. So, why should the cosmos be anything less? His new picture of the cosmos, then, was a world where there was no up, no down, no edge, and no center. The stars, he believed, are distant suns surrounded by planets of their own. And some of these planets may even foster life of their own.

Stoked about his insight, Bruno set out to share his new worldview. Sadly, though, the Inquisition arrested Bruno and put him on trial for heresy. Bruno admitted that he had made some minor theological errors but instead tried to emphasize the philosophical character of his belief. The inquisitors, however, didn’t bite. They demanded that he confess and repent for his sins or burn. Bruno bravely said he had nothing to confess. 

After they read him his death sentence, Bruno looked them square in the face and said, ‘Perhaps your fear in passing judgment on me is greater than mine in receiving it.’ And on that cold February morning in the year 1600, the Inquisitors dragged Bruno through the streets with his tongue in a gag, tied him up, and burned him alive.

Galileo Galilei

A mere ten years later, Galileo Galilei (1564–1642) made an astonishing new discovery with his fancy new telescope—four moons orbit around Jupiter! This discovery refuted the belief that the earth sits at the center of the universe, that everything revolves around it!

The Christian theologians, though, weren’t about to go down without a fight. They ordered Galileo not to hold, teach, or defend heliocentric ideas. So, the clever Galileo wrote a book and, to protect himself, framed it as a hypothetical discussion among three friends about the validity of the heliocentric model. His ploy worked initially, though the Church required him to add a preface acknowledging that the Church’s objections to the heliocentric model were perfectly valid. So, Galileo went ahead and added a brilliantly sarcastic preface: “Several years ago there was published in Rome a salutary edict which, in order to obviate the dangerous tendencies of our present age, imposed a seasonable silence upon the…opinion that the earth moves.”

The book was an immediate success. But it wasn’t long before the Church caught onto his sarcasm. Galileo played dumb at first and claimed that the Dialogue was clearly hypothetical, that he was neither promoting nor defending the heliocentric model. But the head of the Inquisition called bullshit and threatened Galileo with ‘greater rigor of procedure’ — aka, torture — if he wouldn’t confess his sins. So, like a good little deacon boy, Galileo bent over and obediently confessed his sins.

Because of his cofession and largely thanks to Galileo’s popularity, he got a much better deal than Bruno. But still, Galileo was sentenced to house arrest for life and his book was added to the Index of Forbidden Books. Outside the reach of the Inquisition, however, his book spread like wild fire. And just over a quarter-century after Galileo’s death, the geocentric model was abandoned. The Ionian tradition was back in full swing. 

Galileo’s observational refutation of the geocentric model of the universe was remarkable, for sure. But he didn’t stop there. Before Galileo, nobody had challenged Aristotle’s claim that the heavier an object is, the faster it will fall. Galileo, though, not one to take people at their word, decided to build a ramp, place two balls of different weight at the top, and let them go.

If Aristotle was right, the heavier ball should have rolled down the ramp faster than the smaller ball. But as you know, that’s not the case. No matter the weight of the ball, each time Galileo rolled the balls down the ramp, they would move at exactly the same speed. In one fell swoop, then, Galileo not only refuted the great Aristotle, the man who for centuries was simply referred to as The Philosopher, but he also discovered a universal rate of acceleration, thereby clearing the way for Kepler, Newton, and Einstein to improve our understanding of gravity. [1]

Johannes Kepler

Now, before we finish out this episode, let me speak for a moment about Johannes Kepler (1571–1630), one of the people to whom I have dedicated this book. Kepler was among the most honest and humble, yet relentless seeker of truth. And perhaps more than any of his contemporaries, Kepler understood that the only way to move nearer to truth is through the humble method of trial and error.

Inspired by his love for harmony in music, mathematics, and god, Kepler sought to understand the planets’ relations to the sun. But no matter how harmonic a hypothesis was, Kepler didn’t let his metaphysical belief in a divine harmony override observational refutations. Though Copernicus’ idea of circular orbits was certainly harmonic, Kepler humbly discarded it after it was refuted by the astronomer Tycho Brahe’s observations. And so Kepler went back to work.

He understood that when you’re faced with a problem, all you can do is guess. And if you wanna know if your guess holds any truth, you gotta test it empirically. This he did over and over again. Many times in his writings, he says that he approached his search for truth by first formulating a hypothesis and then discarding it if it was refuted by observation. It took Kepler dozens of failed attempts before he finally created the elliptical theory of the orbits.


Though it was Kepler who seemed to have best understood how knowledge is created, it was actually his mistaken contemporaries Francis Bacon (1561–1626) and René Descartes (1596–1650) who received all the hype for their epistemologies, or theories of knowledge. And because vestiges of their mistaken epistemologies remain to this day, we will explore each of them in the next episode.

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