Giordano Bruno was a 16th century philosopher, theologian, and monk who was an early supporter of Copernicus’s heliocentric model of the universe. He was also burned at the stake by the Catholic church in 1600 at the age of 42 after being found guilty of heresy by the Roman Inquisition. That combination of circumstances has sometimes led to him being portrayed as the first martyr for modern science at the hands of religion. The somewhat ominous-looking image of the bronze statue of the brooding Bruno that is sited at the location of his execution in Campo de’ Fiori in Rome has become iconic.

The opening episode of Cosmos hosted by Neil DeGrasse Tyson (that I did not see) apparently had an extended tribute to Bruno. Corey S. Powell summarizes what Tyson supposedly said about him.

Starting in the late 1500s, Bruno argued not only in favor of Copernicus’s sun-centered cosmology, he also proposed that space was infinite in extent; that stars were other suns, surrounded by other Earths; and that those other worlds were also populated.

His belief in an infinite universe, reflecting the infinite glory of God, got Bruno shunned and exiled from country after country. He grew impoverished and largely friendless, but refused to recant. Eventually Bruno was imprisoned by the Church, and burned at the stake in 1600–10 years before Galileo announced his first observations that confirmed Copernicus was right.

Powell says that this story is either misleading or wrong. Although Bruno is fascinating for many reasons, he was not the first to propose the idea of an infinite universe, he was not an astronomer, nor was he even much of a Copernican. What he was was a theological and philosophical innovator who postulated endless inhabited worlds and this is mainly what got him into trouble with the church.

The Roman Inquisition listed eight charges against Bruno. His belief in the plurality of worlds was just one. The others involved denying the divinity of Jesus, denying the virgin birth, denying transubstantiation, practicing magic, and believing that animals and objects (including the Earth) possessed souls. You could fairly call Bruno a martyr to the cause of religious freedom, but his cosmic worldview was neither a deduction nor a guess. It was a philosophical corollary of his heterodox belief that God and souls filled all of the universe.

So there were plenty of reasons for the church to be angry with Bruno that had little to do with Copernican astronomy but everything to do with the determination of the church to maintain its rigid orthodoxy on doctrinal issues. Powell goes on to say that other elements of the common story about the man are also false.

Despite his heresies, Bruno was neither impoverished nor alone. In reality, he had a series of powerful patrons. In 1579, he was appointed a professor of philosophy in Tolouse, France. In 1581, King Henry III of France offered him a lucrative lectureship at the Sorbonne. In 1583 he visited England, lived with the ambassador to France, and met regularly with the Court…and so on. The gaunt, lonely fellow you see on screen in Cosmos is not the real Bruno.

Nor was Bruno the simple, humble figure shown on TV. A major reason he moved around so much is that he was argumentative, sarcastic, and drawn to controversy. He engaged in bitter academic disputes, many of which had nothing to do with his cosmic framework. One example He fled France because of a violent dispute about the proper use of a compass (seriously).
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Bruno’s impassioned statements and outrageous personality alienated many of his natural supporters. Neither Johannes Kepler nor Galileo thought much of him. Kepler even wrote specifically to refute Bruno’s ideas.

So Bruno was a prickly character both intellectually and personally. But nevertheless, the story of Bruno is a compelling one and shows the intolerance of the church for people with heterodox views. As Powell says:

None of this means that Bruno in any way deserved his fate. But neither does he deserve to be reduced to a cartoon about intellectual freedom. He was a brilliant, complicated, difficult man.

Powell goes on to discuss the life of a much-lesser known astronomer and popularizer of science named Thomas Digges whom he says contributed much more to the eventual acceptance of Copernicanism and the idea of an infinite universe. In 1576 he published the first English translation of Copernicus’s De Revolutionisbus. Powell compares Bruno and Digges.

Bruno was a pugilist and an ideologue. In many of his ideas he was right–wildly, spectacularly right–but his method of spreading his ideas alienated his supporters. More importantly, his ideas sprang from faith nearly as much as did the ideas of the Church; Bruno was far from a scientist in the modern sense.

Digges, in contrast, was focused on advancing the work of Copernicus. He helped lay the intellectual groundwork for Kepler and Galileo, and established England as a beachhead of progressive scientific thought.

One of the things I have learned is that the history of science as told in science textbooks is not to be trusted. In fact, I have written two articles that tried to set the record straight in two areas, that Columbus was not the one who proved that the Earth was round and correct some of the many myths surrounding the Copernican revolution, especially the one that it was initially opposed because it represented a demotion for human beings because it implied that the Earth was no longer the center of the universe.

Of course, there is likely to be no definitive account of someone who lived over 400 years ago and Powell’s criticism of the way that the Cosmos show portrayed Bruno has been challenged by Steven Soter, one of the co-writers of the series, who says that Bruno’s scientific insights, especially the one that the Sun and other stars were similar things. were not insignificant, leading to a bit of back and forth with Powell standing by his argument that Bruno’s troubles with the church due to his heresies were caused primarily by theological differences, rather than those originating in science.

In a subsequent exchange, Soter and Powell get into more detail about the significance of Bruno’s scientific insights. In the end, Powell makes an important point about a common trap that we can fall into in looking back at scientific history.

First, we sometimes regard ourselves as inherently smarter than those in the past, simply because we start from a place of greater understanding. Such casual arrogance overlooks the incredible efforts required by people like Bruno, Digges, and thousands–no, millions–of others who have contributed to science and to the great march of human knowledge.

Second, there is a tempting inclination to view the past as a prelude toward an inevitable present. This attitude, which has been known to afflict academics as well, is known as Whig history. I still think Cosmos fell prey to this error, in trying to make Bruno’s universe look too much like our own. Seen in clear-eyed historical context, Bruno’s views still strongly resembled the spiritually ordered Church universe of the time–not to mention the philosophies of his ancient Greek influences, Lucretius and Anaxagoras.

This is a great exchange of essays, though to fully appreciate them one has to have a taste for historical detail. The histories we learn from physics textbooks are all too often oversimplified in the cause of quickly making some point and should be treated with caution. The real histories are much more interesting and complex. But to read those you have to seek out the writings of historians of science or physicist authors who have taken the trouble to become familiar with such works.