Giordano Bruno’s Boundless Universe by Paradox

an introduction to thought experiments

Giordano Bruno’s life story is an interesting way to introduce thought experiments because it involves an interesting true story, an interesting pure thought experiment, and the tragic elements woven into so many intersections of truth and thought.

The true part is the story of Giordano Bruno. This Dominican priest lived in Italy in the late sixteenth century. Bruno was far from Italy’s most obedient priest and did everything he could to read the books banned by the Roman Catholic Church, which included countless texts by Greek philosophers.

Zeno’s Arrow Paradox (adapted)

In one of these texts, likely Aristotle’s Physics, the Greek philosopher, Zeno, posits a situation.

In this situation, which is part of Zeno’s paradoxes of motion, a man shoots an arrow from a fixed position. The arrow can either hit something or continue flying and never stop. If the arrow hits something, then another arrow can be fired from that obstacle. The arrow must keep traveling, or it will encounter an obstacle from which another arrow can be fired. Following this line of reasoning, space must be boundless. It’s important to note that this is a slant on Zeno’s arrow paradox that fits Bruno’s eventual viewpoints. Zeno’s methods of reasoning are very early and noteworthy examples of proof by contradiction, a favorite of Socrates. Zeno’s arrow paradox does involve space and time, but in a way that is far too simplistic to answer Bruno’s existential questions.

Bruno read these paradoxes and many other thought experiments. He fell asleep one night and had a dream that would change his life. This dream would also cause the end of his life, in time.

Bruno’s Dream

One night, as Bruno dreams, he sees the universe. To him, it seems flat, somehow unmoving, and fake. The universe, as he was viewing it, was likely as it would have been known during his time: geocentric. The Earth rested at the center of the universe, with everything revolving around it. Humanity’s understanding of the nature of the universe was very primitive at this time and was conjecture, at best. The geocentric universe is what, according to the Church, gave humanity it’s uniquely divine connection. Copernicus had already introduced his heliocentric theory and it was widely publicized, and he had been essentially exiled because of the nature of his theory and his lack of evidence to support it.

Bruno sees that there’s something wrong with this view of the universe. Realizing this, he ventures further into his dream. What are all the points of light in the night sky? Is this a simple globe that we, on Earth, can only see from within? Surely, a simple rotating map or projection couldn’t be all that exists.

Suddenly, he realizes that everything within his view is a curtain that he can pull back. Once he has done so, he can see that there’s nothing different between our sun and all the other stars in the universe. What used to be a static map on the inside of a sphere was now countless versions of our own sun: stars. He saw that the Earth revolved around the Sun, and all the other stars were just like the Sun, many had their own planets revolving around them, and that the universe had no center, beginning, or end. Bruno’s vision was remarkably accurate, more accurate than even Copernicus had posited. That point raises a question, which I’ll address later.

How Bruno Failed

Bruno was elated at this view of the universe, and he had reason to be. He was likely the single most truly enlightened person in all of humanity, certainly among his contemporaries in the Western world, regarding the nature of our universe. The Roman Catholic Church did not share his elation. After traveling the Western world to present his ideas, which were rejected at a variety of prestigious establishments, he eventually returned to Italy, where he was convicted of heresy by the Inquisition and burned for his crimes.

Experimentation and Application

There are lines of distinction to be drawn, here. The thought experiment is simply Zeno’s arrow paradox. It exists only to explain a sticking point in philosophy, and that sticking point is not the bounds of the universe.

The application of this experiment to our physical universe and the nature of its bounds by Bruno extends beyond a thought experiment. While Bruno was correct in his view, it was impossible to prove. While he is often cited as a martyr for science, I personally see him more a martyr for freedom of thought (which is no less important). While he was persecuted for thoughts that were correct, he did very little to provide proof for his views, and they were rejected. He knew the nature of the much more immediate universe in which he lived, and because he didn’t work within the construct of his society, he was imprisoned and executed. It wasn’t until the invention of the telescope and the resultant observations and mathematics that his views were shown to be correct.

The Nature of Bruno’s Martyrdom

It’s important to note that, while Bruno was a martyr for science in a way, his story is also illustrative of the importance of truth.

Looking back, it’s easy to view Bruno in an overly favorable light, but it’s important to remember that he had no more evidence than the Church had regarding the construct of the universe. He wasn’t the only or first person to have a vision of the universe, and he could easily have been incorrect. Bruno spent the rest of his free life telling people about his ideas and presenting them as a new divine truth, but spent virtually no time attempting to prove them. It’s also important to note that Bruno’s views on a boundless universe were not his only controversial views and that many historians find it likely that these ideas weren’t the crux of his trial.

Galileo later proved irrefutably that Bruno’s ideas were correct, but not for vindication of Bruno or by building on his work. Galileo’s work in physics was based on observable fact and thus could have countered Bruno’s vision. He may have agreed with Copernicus and Bruno, but his study was based on scientific observation and the fact that a question was unanswered. In other words, this unity of thought was a coincidence.

The Question

I mentioned a question that should be raised, and it's this: If Copernicus, a scientist and physicist, was unable to prove his theories, how could Bruno have hoped to do so?

The answer is that he had very little hope, and he didn’t try. This question was more decisive during Bruno’s time than it is now, but it’s still important. He was comparatively uneducated, and wouldn’t have had access to what he would need to prove his theories, even before he was imprisoned. Information was not as available as it is today, but the points of knowledge and understanding still remain.

Bruno as a Role Model

Bruno’s story illustrates the problems that happen with conviction without proper reasoning. Bruno knew he was right; he was convinced. His conviction wasn’t based in reality, and even though his ideas were correct, they occurred in a construct where freedom of thought was not guaranteed. Even with proof, his fate could easily have been the same. Without proof, he knew he stood no chance. His death went largely unnoticed in February 1600.

Bringing this to an individual perspective, while you can easily come to the belief that you’re correct, be careful in using that self-conviction to counter others. If your entire belief is self-validated, it’s merely an opinion among many. People may believe you, but they will also be doing so without reason. The belief of others may further validate your idea but does nothing to prove it. This is where opinion and truth separate, and while there is nothing wrong with either, they serve different purposes.

Note: This essay isn’t meant to be a historical account or textbook explanation of the lives and ideas of Bruno, Zeno, Aristotle, Socrates, Copernicus, or Galileo. That’s quite the long story, to say the very least. While I’m unaware of anything that’s factually incorrect here, this piece is meant to explain problems that can occur when ideas are misinterpreted and people operate outside of the limitations of themselves, their society, and reality.