Swimming the Tiber 34: Eppur Si Muove

Let Us grant you that all of your demonstrations are sound and that it is entirely possible for things to stand as you say. But now tell Us, do you really maintain that God could not have wished or known how to move the heavens and the stars in some other way? We suppose you will say ‘Yes,’ because We do not see how you could answer otherwise. Very well then, if you still want to save your contention, you would have to prove to Us that, if the heavenly movements took place in another manner than the one you suggest, it would imply a logical contradiction at some point, since God in His infinite power can do anything that does not imply a contradiction. Are you prepared to prove as much? No? Then you will have to concede to Us that God can, conceivably, have arranged things in an entirely different manner, while yet bringing about the effects that we see. And if this possibility exists, which might still preserve in their literal truth the sayings of Scripture, it is not for us mortals to try to force those holy words to mean what to us, from here, may appear to be the situation.

– Pope Urban VIII to Galileo Galilei, quoted
by Giorgio de Santillana in The Crime of Galileo

I do not therefore consider them [your arguments] true and conclusive; indeed, keeping always before my mind’s eye a most solid doctrine that I once heard from a most eminent and learned person, and before which one must fall silent, I know that if asked whether God in His infinite power and wisdom could have conferred upon the watery element its observed reciprocating motion using some other means than moving its containing vessels, both of you would reply that He could have, and that He would have known how to do this in many ways which are unthinkable to our minds. From this I forthwith conclude that, this being so, it would be excessive boldness for anyone to limit and restrict the Divine power and wisdom to some particular fancy of his own.

– Simplicio in Galileo Galilei, Dialogo sopra i due
massimi sistemi del mondo
, trans. Stillman Drake

The well-read among you may recognize the title of this post as the words of Galileo sometime shortly after his recantation of heliocentrism. You may hear the phrase in English (“And yet it moves,” referring to the Earth) as a petulant retort to an authority figure who denies your view (whether factual or not).

For what it’s worth, the Church has apologized for the way Galileo was treated. Personally, I don’t think it had to. The Church was, in the first place, eminently reasonable throughout the Galileo affair; in the second place, his treatment was among the most civil of anyone found guilty in an inquisition.

Galileo’s biggest problem wasn’t the Church; it was his contemporaries and colleagues. Copernicus was slow to publish his position on heliocentrism (which he dedicated to the pope) not because he was afraid of the Catholic Church, but because he could not answer the principal objection: that there were no observed parallax shifts in the stars (mainly because that technology wouldn’t be available for another couple hundred years). For the same reason, Johannes Kepler was poorly received by his contemporaries; one of those contemporaries, Tycho Brahe, rejected Copernicus’ model of the solar system (in favor of his own convoluted Tychonic system, where non-Earth planets revolved around the sun, but the sun still revolved around the Earth).

But Galileo was so convinced he was right (he wasn’t, by the way–his model posited that the sun was the immovable center of the universe, and we know that it is not, but rather it orbits the center of our galaxy, which is itself moving) that he began to proclaim his scientific opinion as scientific fact without much evidence to back it up. His contemporaries (most of whom held to the Tychonic system and the rest supported the Ptolemaic/Aristotelian system) opposed him intellectually, but he really got himself into hot water when he touted this as ample reason to change the established interpretation of Scripture.

You see, in 1610, Galileo had his famous encounter with the moons of Jupiter through his telescope. That, along with the phases of Venus, disproved the geocentric model in his mind. (His contemporaries replied that the Tychonic system answered those objections just fine.) In 1611, a dear friend of his wrote to him, “I write because men like you are of great value, deserve to live a long time for the public benefit, and I am also motivated by the particular interest and affection which I have for you and by my constant approbation of you and your work.” (Maffeo Cardinal Barberini in a letter to Galileo Galilei on 11 October 1611, recorded in Le Opere di Galileo Galilei, Edizione Nazionale, Vol. XI (Firenze, 1901), p216)

Fast-forward a few years. Galileo belligerently accosted the intellectuals of the Catholic Church, with whom he had formerly had an accord. He flatly rejected that heliocentrism should be presented as a competing model (lacking further evidence); instead, he compelled Church authorities either to accept heliocentrism (and thereby change the traditional interpretation of Scripture, which they had no cause to do, since heliocentrism could not answer its toughest scientific opposition) or to condemn it as heresy (which they were not wont to do under the circumstances).

By 1624, Galileo was having regular meetings with his old friend, Cardinal Barberini–only now, Barberini was Pope Urban VIII. The pope took these meetings as an opportunity to share his own philosophy with Galileo (the first quote at the top of the page). The pope reasoned with him that, although Galileo’s opinions were very well thought-out, wasn’t it possible that God, in his omnipotence, could have done it some other way? (Surprise! God did. See above about the sun also being mobile.) 1624 is the earliest reasonable date for the quote at the top of this page from Pope Urban VIII. The pope promised to continue supporting Galileo, provided the man slack off a little on his zeal.

Galileo’s response was to write the Dialogue Concerning the Two Chief World Systems in 1632. The dialogue mostly follows three men: Salviati (who argues for Galileo’s views), Sagredo (who starts out neutral but quickly follows Salviati), and Simplicio (an ardent supporter of the Ptolemaic system). Just as Salviati was named for one of Galileo’s friends and Sagredo for another, Simplicio is ostensibly named for Simplicius of Cilicia (a 6th century commentator on Aristotle)–but even those of us who do not speak Italian can plainly see the double entendre with simpleton and the like. Based on his poor argumentation style and rapid loss to Salviati, the pun seems intentional.

Which brings us to the second quote at the top of the page, when Simplicio is used as a mouthpiece for the pope’s own view. Galileo even makes it obvious, in case you missed it–Simplicio heard this theory “from a most eminent and learned person,” and then he nearly quotes his one-time friend word-for-word.

The pope was still a man, and he had his pride. Getting on his bad side was not beneficial to Galileo’s argument; on top of that, the pope had plenty of political problems of his own. Galileo could not prove his position, but he insisted on changing Catholic teaching anyway; that way lies heresy, which is what he was ultimately accused of. After the inquest, he recanted (though popular legend, spreading almost as soon as he died, claims his petulant response) and was confined to his homes for the remainder of his life (not a dungeon).

Later (over two hundred years later, in 1838), Friedrich Bessel discovered stellar parallax, definitively proving the heliocentric solar system (but still not Galileo’s heliocentric universe). Bans of pro-heliocentric views had been completely lifted by 1835, even allowing uncensored editions of Galileo’s most audacious works. As with other scientific developments (more on that in a couple of months), once the majority of scientists support a particular theory, the Catholic Church respectfully allows its interpretation of Scripture to match God’s Creation.

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A Serious Issue