“Four centuries after Galileo was silenced”, a headline blares, “UK students are still curbing free speech.” (At issue was a student union’s no-platforming of Julie Bindel and Milo Yiannopoulos.) “Whether it’s Galileo’s heretical rejection of geocentrism, Darwin’s godless theory of creation or the bravery of dissidents resisting oppression all over the world,” a Telegraph op-ed against “safe spaces” intones, “history shows that the right to disagree is the cornerstone of intellectual and political freedom.” A National Review diatribe about the campus “war on free speech” likens the case for giving climate change denialists platforms today to that for hearing Galileo in the 1630s. “Galileo was arrested for spreading ‘fake news’”, trumpets a denunciation of “left-wing” censorship. And just yesterday, in the course of a Twitter discussion on the relative unimportance of staged debates in disciplinary research and teaching, a campus free speech advocate chimed in to say that “Galileo would disagree.”
These invocations of Galileo are certainly not all the same. Stephen Pumfrey, a historian of science and the author of the first piece linked above, carefully notes that “People in all ages have accepted that there are limits to public discourse. There is no unfettered freedom of expression… What changes over time and place is what those limits are, who sets them, on what authority and why.” (I disagree with his analogy between Galileo’s persecutors and the student union, but he does qualify it.) But many more are more apt to equate Galileo with the cause of “free speech” or “free expression” or “open debate” without any such qualification. Running through most of them is a series of more or less convenient confusions — in particular, equating the freedom of speech with access to particular platforms — and a deep and equally convenient ignorance both about how research and teaching work and about their seventeenth-century free speech hero’s own thoughts on the subject.
I’d like to deal first with some of the more obvious limits of the comparison between Galileo and contemporary transphobes, climate change denialists, and neo-Nazis. Is it fair to consider the relative merits of the content we’re talking about in each case? Is Nazism an exciting new idea that needs a hearing to be responsibly assessed? Are we really so unfamiliar with attacks on trans people that we need give them a stage on campus to figure out what these new thoughts might be? The comparison seems questionable. But let that be; we can leave content out for the sake of principle. After all, people found Galileo’s ideas objectionable, too — and harmful, in that they fomented heresy. One might even argue that they were not new, inasmuch they could be linked to ancient antecedents. “Oh no”, we can imagine young Paduan snowflakes groaning as Galileo strode towards the lectern, “not this Aristarchian crap again.”
On the other hand, Galileo did not travel with armed thugs. No one going to hear him speak, or to protest his speech, was liable to be shot at by rabid heliocentrist gangs. Nor did Galileo have access to an especially wide variety of platforms for publicizing his ideas, though he made good use of those he had. Students denying Milo a stage on their campuses or in their communities are not silencing him altogether, much less policing his thoughts. But the Church did indeed claim power not only over university teaching, but also over the licensing of printed works, and, of course, the content of belief itself. Policing ideas was precisely the point of the Church’s condemnation of Galileo. At the very least, then, the analogy between Galileo and Milo Yiannopoulos or Richard Spencer or even Charles Murray is severely compromised by the different contexts in which each operated, by differences in the nature and especially the scope of the opposition each faced, as well as by what was at stake for the people and the ideas at issue in each case — or, to put it another way, by the different kinds and distributions of power in play.
All analogies are flawed, of course. But the idea of Galileo as a champion of unfettered free speech or debate is also wrong in itself, and not only because the formulation is ahistorical. Consider the Dialogue Concerning the Two World Systems (1632), the work that provoked Galileo’s trial and conviction in 1633. As was not unusual in the early modern period, the Dialogue set out its author’s ideas in the form of a conversation between several interlocutors representing different points of view. It was thrown up at me yesterday as evidence of Galileo’s belief in producing knowledge through open “debate”. But there is a world of difference between a live conversation between people with different views and independent minds and a written dialogue in which a single author puts the words he chooses in his opponents’ mouths. (This, indeed, was part of what got Galileo into trouble.) A dialogue scripted so that one side wins is a compelling rhetorical device. But it is not a research methodology, and it is not a debate.
Still better, consider Galileo’s letter to the Grand Duchess of Tuscany. He wrote it in 1615 to deflect the accusations of heresy that would lead the next year to the fateful edict against his Copernican teaching — the basis for his later trial and condemnation. The letter sets out his views on how, and by whom, scientific questions should be debated. Accused of contradicting the Bible by asserting heliocentrism, Galileo had this to say:
[T]he holy Bible can never speak untruth – whenever its true meaning is understood. But… it is often very abstruse, and may say things which are quite different from what its bare words signify. … These propositions uttered by the Holy Ghost were set down in that manner by the sacred scribes in order to accommodate them to the capacities of the common people, who are rude and unlearned.
His opponents were not wrong in following the Bible, in other words, but wrong in reading it literally rather than metaphorically or allegorically. It was not a physics textbook but a religious text, written for the weak wits of “common people.” Literal readings of it, accordingly, were not legitimate criticisms of scientific observations:
For that reason it appears that nothing physical which sense-experience sets before our eyes, or which necessary demonstrations prove to us, ought to be called in question (much less condemned) upon the testimony of biblical passages which may have some different meaning beneath their words.
Galileo was not arguing here for “open debate” or “free speech”. To the contrary, he was attempting to set rules for the assessment of scientific claims — rules that specifically excluded certain kinds of objection, and certain kinds of critic. He was not arguing, to put it in the current terms of the “free speech” debate, that “all perspectives are valid” and worthy of consideration. He was in fact arguing specifically that some are not.
In effect, Galileo attempted to set the limits of a space (one is tempted to call it a “safe space”) in which only those with pertinent expertise were to be taken seriously — and within which a certain kind of intellectual activity could be protected from exogenous attack. Science, the investigation of nature, was one such space. Theology was another, and theologians should keep to it. If this sounds “elitist”, it was; Galileo distinguished not only between theologians concerned with faith and men like himself concerned with “reason and the evidence of our senses”, but also between both and the “herd” of “rude and unlearned people” for whom knowledge of the truth was neither necessary nor attainable. (Nor, indeed, desirable; Galileo agreed that religious “confusion in the minds of the common people… would render them contumacious toward the higher mysteries.”) We need not, I hope, share this vision of the social hierarchy to recognize the importance of disciplinary standards in promoting and protecting the creation of knowledge. But if you think that the advancement of knowledge requires universities to treat all perspectives as equally valid, don’t call on Galileo. He disagrees.
 The version quoted below is printed in Stillman Drake (trans.), Discoveries and Opinions of Galileo (New York: Anchor, 1957), 173-216.