How simplistic narratives can mislead us: a case study of the Galileo affair

"Of course, everyone knows that in the Middle Ages the Roman Catholic Church burned scientists at the stake for their scientific beliefs." Such claims aren't uncommon on university campuses. It's "common knowledge" that science and religion are locked in perpetual conflict. After all, didn't people, informed by their religion, believe that the Earth was flat well into the Middle Ages or even later? Wasn't Copernicus hounded by Christians for demoting the Earth from its privileged place at the center of the cosmos? Didn't the Church torture Galileo for defending heliocentrism?

As it happens, none of these stories are accurate. Yet anecdotes about religion suppressing science are part of a broader cultural narrative of conflict where science and religion have been locked in a zero-sum struggle - when science advances, religion is forced to beat a hasty retreat. This view of the historical relationship between science and religion is called "the conflict thesis" (see here, here, here). Although it is almost universally panned by historians of science and religion, it remains popular, even in some academic circles. But simplistic narratives like the conflict thesis aren't innocuous - they can warp our understanding of history (for example, here and here the historians of science Stephen Snobelen and Seb Falk address the myth of the "Medieval Gap," which is grounded in the conflict thesis, as promulgated by writers like Carl Sagan, Jerry Coyne, and A.C. Grayling).

As university instructors, we are responsible not only for the production of knowledge but also for its dissemination. If simplistic narratives inhibit our ability to produce and disseminate knowledge, that implies we have an obligation to foster the capacity to handle complexity - in ourselves, in our students, and in the broader public.

The Galileo Affair

The Galileo affair is a case in point. In popular culture, suffused with the conflict thesis, Galileo is portrayed as having been vilified, even tortured by the Roman Catholic Church, which, tenaciously holding to blind faith, denied plain facts. Historians have spilled oceans of ink to counter false narratives of this kind, but the ease and simplicity of the conflict thesis means that the evidence historians present - which paints a far more complex picture (see here, here, here) - reaches and persuades few.

History is multidimensional. This means that if we want to see how the conflict thesis warps our understanding of history, we have to dig into the details. In what follows, I will offer a narration of the Galileo affair while attempting to point out the various axes around which the story turns. I want to suggest that the Galileo affair must be understood as having at least four axes: religious, scientific, philosophical, and political.

The Religious Axis: Catholic vs. Catholic

What did happen to Galileo? In short, in 1633 Galileo was found guilty of "vehement suspicion of heresy," forced to recant his belief in heliocentrism, and sentenced to house arrest for the rest of his life. This incident is perhaps the strongest case for conflict between science and religion. Yet, even here the issue is far more complicated than many realize.

Decades earlier, in 1615, Galileo, a somewhat recent convert to heliocentrism, was accused of heresy by the Dominican monk Niccolò Lorini. The accusation was prompted by Galileo's Letter to Benedetto Castelli (1613), which argued for the compatibility of heliocentrism with scripture. To make this case, Galileo employed a standard Augustinian argument that God would have accommodated the language of scripture to the comprehension of the unlearned people for whom the Bible was written; therefore, it shouldn't be taken as a guide to the physical nature of the universe.

To us, this argument may seem innocuous. But Galileo made this argument in the wake of the Reformation, when there were ongoing, intense debates about who had the authority to interpret scripture. In the eyes of some in the Church, Galileo was abrogating the Church's authority by instructing fellow Catholics in biblical interpretation as a layperson. Implying that the authority to interpret the Bible lay with someone other than the Church was a risky move for a Catholic during the Counter-Reformation. In other words, Galileo, while a loyal Catholic, sounded too much like a Protestant. What has become emblematic of a conflict of science versus religion began as an intra-religious conflict about who had the authority to interpret the Bible.

The Scientific Axis: The Church Sides With the Scientific Consensus

The episode prompted the Church to formally examine heliocentrism. Despite Copernicus broaching the topic in 1543, the Church had no official position on heliocentrism, apparently preferring to leave it to the natural philosophers and astronomers to sort out. Galileo himself went to Rome to defend heliocentrism, though historians argue that his combative style likely only harmed his cause and reputation. In 1616 the Holy Office ruled that heliocentrism was "foolish and absurd in philosophy" and contrary to scripture. The ruling was followed by an order that Copernicus' work (a particular version of which Galileo was defending) be temporarily suspended until the necessary edits were announced (see a "corrected" copy of Copernicus' De Revolutionibus).

Historians still debate the motivations for such a ruling, yet as the philosopher and historian Maurice Finocchiaro points out - and contrary to what the conflict thesis would lead us to believe - the objections to heliocentrism at the time "were not just religious, theological, and scriptural, but involved considerations ranging from the astronomical and physical to the epistemological and methodological." The Church was perfectly aware of the scientific and philosophical objections to heliocentrism and deemed the weight of the evidence to be against the physical truth of heliocentrism (hence the language that it was "foolish and absurd in philosophy"). After all, if the problem was purely scriptural, the Church had established interpretative tactics for dealing with apparent conflicts between the Bible and natural philosophy (including the doctrine of accommodation) and could have availed itself of such means if it felt compelled to do so.

The reality is that the weight of the scientific evidence was simply not firmly on the side of heliocentrism when the Church issued its 1616 ruling. At that time, and contrary to Galileo, most natural philosophers regarded Copernicus' heliocentric model only as a useful calculating device, not an accurate picture of the physical universe. The distinguished historian of science and religion, Peter Harrison, notes that the Church was essentially endorsing the scientific consensus of the time. But why were most of Galileo's colleagues opposed to heliocentrism?

For one thing, heliocentrism was incompatible with the only comprehensive physics of the day - Aristotle's. For another, astronomers were aware that there had been no observation of stellar parallax, which, given the state of knowledge of the time, was a powerful argument against heliocentrism. Not even Tycho Brahe, the greatest observational astronomer of the sixteenth century, could find it; partly for that reason, he rejected the Earth's motion. As historian David Lindberg puts it, "Those astronomers and natural philosophers who rejected heliocentrism did so not because of blind conservatism or religious intolerance, but because of their commitment to widely held scientific principles and theories." In short, many rational, fully informed people perceived Galileo to be on a fool's errand; the Church seems to have agreed.