[Also see my related post “Why Galileo is Not ‘The Father of Modern Science.”]
The myth of “Galileo as a martyr for Science” is one of modernity’s cherished foundational myths. And of course, being a myth, it is almost entirely historically false. Just about anything you think you “know” about the Galileo affair is probably wrong. At any rate, an examination of the history of the Galileo affair does not in any way, shape, or form bear out the idea that either Christianity in general nor the Catholic Church in particular is or ever was hostile to or opposed to science. This “moral of the story” simply cannot be drawn from the facts.
The TL;DR is that Galileo was an intemperate, arrogant ass with almost no sense of propriety, and so blindly convinced of the absolute truth of his Copernicanism that he could accept no dissent, even when he had no good evidence for it, and even after the evidence against it became conclusive. The best that can be said for Galileo, perhaps, is the argument of Alice Drager that such arrogant and narcissistic personalities have sometimes played a role in scientific discovery, and that scholars are often “Galilean personalities”—which explains why most academic squabbles are so full of bile and venom. Academics are often asses, and that most certainly includes scientists, although in no way limited to them. Galileo made some important advances in physics (although almost all were discovered by others also around the same time), made some contributions to astronomy (mostly simply by dint of being the first of many), and generally treated his fellow human beings (except his daughter) very poorly, including his friends and his scientific colleagues. He did not possess the virtues of a scientist. He was arrogant, dogmatic, vain, malicious, venomous, enjoyed ridicule, picked unnecessary fights, and was generally an unpleasant person, except when he was fawning on those of higher station.
I quote David Bentley Hart on the affair. Those interested may read his excellent account in his Atheist Delusions, Chapter 6, from which this excerpt is taken:
Galileo, it must be said, squandered good will with remarkable abandon. He was, not to put too fine a point on it, selfish, irascible, supercilious, vicious, and mildly vindictive. He could not abide rivals, resented the discoveries of others, refused to share credit with astronomers who had made observations of the same celestial phenomena as he had, and belittled those whose theories differed from his own (his attitude toward Kepler, for example [with whom he professed friendship] was frightful). Incensed that the Jesuit astronomer Orazio Grassi [writing under the pen name Sarsi] had presumed, in 1618, to describe the movements of comets beyond the lunar sphere without mentioning Galileo—who had, as it happens, done absolutely nothing to merit any mention on the subject—Galileo chose to assert that such comets were mere optical illusions [ones created by telescopes, actually recycling some of the exact same arguments that had been used against his own observations of the moons of Jupiter], and for good measure even attacked Tycho’s observations of comets.
Galileo’s personal copy of Grassi’s book is littered with marginal notes such as “Idiocy!” “evil coward!” “ungrateful bastard!” and finally the amazing rant that “You cannot help it, Signor Sarsi, that it was granted to me alone to discover all the new phenomena in the sky and nothing to anybody else! This is the truth which neither malice nor envy can suppress!” Yes, Galileo believed that he had been granted a special dispensation by God to be only one who could make any astronomical discoveries. Truly a very humble “scientific” attitude.
Back to Hart:
He provoked public controversy where none was necessary, once on a mere rumor that his theories had been deprecated in the course of someone else’s dinner conversation. His uncompromising stand for an absolute vindication of his theories precipitated the ecclesial consultation of 1616 that—when it turned out Galileo was unable to provide a single convincing proof of Copernicanism—resulted in the injunction (of great gentleness, actually) admonishing Galileo against teaching the Copernican system as established truth [which of course, being wrong, it was not]. In his absolute and dogmatic Copernicanism, Galileo was equally hostile to his nominal friend Kepler’s entirely correct discovery that the planets move, not in perfect circles, as Galileo believed, but in elliptical orbits, showering his heretofore friend with vicious abuse for his “heretical” Copernicanism.
As for Galileo’s decisive trial in 1633, it was, as Arthur Koestler has noted, “not in the nature of a fatal collision between opposite philosophies of existence … but rather a clash of individual temperaments aggravated by unlucky coincidences.” Pope Urban VIII himself had encouraged Galileo to write his Dialogue Concerning the Two Chief World Systems, The Ptolemaic and the Copernican (1632), enjoining only that it include a statement to the effect that the Copernican theory was a hypothesis and that no scientist could pretend to know perfectly how God had disposed the worlds. Galileo did include such a statement in the dialogue, at its conclusion in fact, but chose to place it in the mouth of the ponderously obtuse character whom he not-very-subtlely named Simplicio, a dogmatic and stupid Aristotelian placed in the dialogue as a foil for the wise and intelligent Copernican Salviati and a comical contrast to Sagredo, the clever scientific novice; worse still, Simplicio is presented rather clearly as caricature of Pope Urban VIII himself, and states that the formula stems from “an eminent and erudite personage, before whom one must needs fall silent.” This was, to all appearances, a tasteless and completely unwarranted insult to a cultured and heretofore generous friend and supporter, and Urban—an Italian gentleman of his age, a prince of the Church, and a man of enormous personal pride (much like Galileo himself)—took umbrage.
More importantly, though, and too often forgotten, Urban was entirely right on one very crucial issue: the Copernican model was in fact only a hypothesis, and a defective one at that, and Galileo did not have either sufficient evidence to support it or a mathematical model that worked particularly well.
Indeed, ironically, at the time Galileo was propounding his doctrinaire Copernicanism in 1633, astronomy had already left him behind, and was debating the alternatives of the Tychonic model versus the Keplerian model. No one but Galileo still embraced straightforward Copernicanism.
The Church hierarchy was perfectly well aware of this. The Catholic Church was not attacking science in censoring Galileo. It wasn’t particularly behaving at its best, but Galileo had publicly ridiculed the Pope, who up until that point had been his friend, and had gotten involved in advocating private scriptural interpretation—not the wisest thing to do in Italy when there is a Protestant Revolution going on.
Though Galileo was far and away the greatest physicist of his age (and indeed of human history to that point [with the possible exception of Aristotle]), he was not even an astronomer in the fullest sense—he was more of a brilliant stargazer—and he seems to have been little interested in the laborious observations and recondite calculations of those who were. He may not even have fully understood the fundamental issues—hence his dogmatic dismissals of the contributions of Tycho and Kepler. He seems not to have cared or understood how impossibly complicated and unconvincing Copernicus’ model of the heavens was. It is not even certain that by 1632 he clearly recalled how the Copernican system actually worked. He did not, as mentioned, avail himself (though he was perfectly and resentfully aware of) Kepler’s elliptical planetary orbits, which were encumbered by none of the inconsistencies and internal corrections and physical impossibilities of the Ptolemaic and Copernican systems. Instead, he insisted along with Copernicus upon the circular movement of the planets, with all the mathematical convolutions this entailed—indeed, insisted on it far more intransigently than Copernicus himself ever did. He had no better explanation than Copernicus for the absence of the observation of stellar parallax, even when the stars where viewed through a telescope. And his most cherished proof of terrestrial rotation—the motion of the tides—was manifestly ludicrous and entirely inconsistent with the observable tidal sequence (he dismissed Kepler’s entirely correct lunar explanation of the tides as a silly conjecture concerning “occult forces.”)
He also referred to Kepler’s entirely correct theory as “childish,” and was so convinced that the 24 hour cycle of the tides “proved” the rotation of the earth, that he refused to listen when Spanish sailors informed him that the tides have 12 hour cycles, not 24 hour cycles. What did Galileo do when confronted by those who knew about tides from “observation and experience”? He dismissed them as ignorant and unlearned of course. The tides had to have a 24 hour cycle, because Galileo needed a 24 hour cycle to “prove” Copernicanism, which was, of course, false. So,
Galileo elected, that is, to propound as absolute truth a theory whose truth he had not and could not demonstrate, dismissing alternate theories which were far superior, while needlessly mocking a powerful man who had treated with honor and generosity. And the irony is, strange to say, that it was the Church that was asking for proof, and Galileo, the “martyr of science,” who was demanding blind assent to the truth—of a model that was provably wrong.
Galileo was very far from an ideal scientist. His discoveries in physics concerning motion would prove to be essential, but his contributions to astronomy were negligible. Here is a lovely and succinct account from the blog The TOF Spot:
Aside: The Crucial Role of Galileo.
There was none. Every discovery made by Galileo was made by someone else at pretty much the same time. Marius discovered the moons of Jupiter one day later. Scheiner made a detailed study of the sunspots earlier than Galileo. The phases of Venus were noted by Lembo and others. And so on. Even his more valuable work in mechanics duplicated the work of De Soto, Stevins, and others. Matters would have proceeded differently — certainly with less fuss and feathers — and some conclusions may have taken longer, or perhaps shorter times to achieve. The thing is, science does not depend upon any single individual. No one is “the father of” any particular theory or practice. As Newton observed, he stood upon the shoulders of giants — a sentiment expressed by Bernard of Chartres back in the Early Middle Ages! Regarding heliocentrism, Galileo’s biggest accomplishment was to get some folks so riled up that the conversation was inhibited for a short time in some quarters.
Indeed, if you want a very thorough (and humorous) walkthrough of the ENTIRE Copernican Revolution, you can’t do better than The TOF Spot’s 9-part series THE GREAT PTOLEMAIC SMACKDOWN. Go read it, and learn.
If you want an in-depth, scholarly account of the Galileo affair (although The TOF Spot does just fine in citing his sources), I refer you to Galileo: A Very Short Introduction, by Stillman Drake, the top Galileo scholar and translator writing in English.
Also see my related post “Why Galileo is Not ‘The Father of Modern Science.”