Follow Galileo or Kepler?


So, @TedDavis and @rcohlers , I came across something that has had me thinking. I want your thoughts and opinion on, partly to make sure I’m not misreading the history.

Kepler and Galileo are both key scientists in the copernican revolution. They faced biblical objections to the science they were bringing forward. The conflict, as Galileo puts it,

The reason produced for condemning the opinion that the earth moves and the sun stands still in many
places in the Bible one may read that the sun moves and the earth stands still. Since the Bible cannot err;
it follows as a necessary consequence that anyone takes a erroneous and heretical position who maintains
that the sun is inherently motionless and the earth movable.

It seems like they took very different approaches to rebutting these objections. They both invoke accommodation appeal to ordinary perception, it seems that Galileo also places science above Scripture, as an inviolable rule of hermeneutics. Kepler, however, does not seem to make this move, but limits himself to a very coherent explanation of the distinction between ordinary perception and scientific knowledge, and its affect on language too. In contrast, Galileo collapses ordinary and scientific perception into the same category, loosing a key distinction.

I’m really curious if this reading is the correct reading. I’m wondering because for years now I’ve really counted Kepler as a wise example to follow. One of my “discussion” partners this last year, in contrast named his blog after The Letter to the Duchess, which was written by Galileo. Reflecting our affinities, it seems like I took a Keplerian approach to Adam, but he took a Galilean approach.

I was recently reading the Letter to the Duchess (, by Galileo. Here are some key passages.

I think that in discussions of physical problems we ought to begin not from the authority of scriptural passages but from senseexperiences and necessary demonstrations; for the holy Bible and the phenomena of nature proceed alike from the divine Word the former as the dictate of the Holy Ghost and the latter as the observant executrix of God’s commands. … For the Bible is not chained in every expression to conditions as strict as those which govern all physical effects; nor is God any less excellently revealed in Nature’s actions than in the sacred statements of the Bible. Perhaps this is what Tertullian meant by these words:

“We conclude that God is known first through Nature, and then again, more particularly, by doctrine, by Nature in His works, and by doctrine in His revealed word.”

From this I do not mean to infer that we need not have an extraordinary esteem for the passages of holy Scripture. On the contrary, having arrived at any certainties in physics, we ought to utilize these as the most appropriate aids in the true exposition of the Bible and in the investigation of those meanings which are necessarily contained therein, for these must be concordant with demonstrated truths.

It really seems like Galileo is saying we must read Scripture after Science (just like the subtitle of my discussion partner’s book)," assuming" all the science is true. This framing of the theology and science turns what is meant to be a dialogue into a monologue. Science becomes a static backdrop that pronounces “truth”, and theology needs to listen quietly and adapt. This order, it seems, is wrongheaded. As George Murphy might say (along with my Concordia colleagues @CPArand) , the ordering is important here. Scripture first (or at least alongside) then Nature, not the other way around.

Despite all the problems with this framing, following Galileo’s lead, this is exactly what my discussion partner wrote, and what I protested last year:

it is hard to endorse an after-science approach to Scripture; reading before or with science would be more grounded.

Confessing Jesus’ authority over all things, including science (Matt. 28:18-20), might have averted their after-science framing too. From the Empty Tomb, it seems untenable to interpret the Gospels after assuming the solid scientific conclusion that men never rise from the dead. Science is blind to the Resurrection and this blindness declares its limits; science cannot bring us to God or speak of when He acts. Therefore, in view of Jesus, why interpret any Scripture after assuming science?

Let us contrast that with Kepler. This article gives a good summary ( Let me pull out the relevant quotes.

Joshua meant that the sun should be held back in its place in the middle of the sky for an entire day with respect to the sense of his eyes, since for other people during the same interval of time it would remain beneath the earth. That thoughtless persons pay attention only to the verbal contradiction, "the sun stood still‟ versus "the earth stood still‟, not considering that this contradiction can only arise in an optical and astronomical context, and does not carry over into common usage. Nor are these thoughtless ones willing to see that Joshua was simply praying that the mountains not remove the sunlight from him, which prayer he expressed in words conforming to the sense of sight, as it would be quite inappropriate to think, at that moment, of astronomy and of visual errors. For if someone had admonished him that the sun doesn’t really move against the valley of Ajalon, but only appears to do so, wouldn’t Joshua have exclaimed that he only asked for the day to be lengthened, however that might be done? He would therefore have replied in the same way if anyone had begun to present him with arguments for the sun’s perpetual rest and the earth’s motion.

Now God easily understood from Joshua‟s words what he meant, and responded by stopping the motion of the earth, so that the sun might appear to him to stop. For the gist of Joshua‟s petition comes to this, that it might appear so to him, whatever the reality might meanwhile be. Indeed, that this appearance should come about was not vain and purposeless, but quite conjoined with the desired effect (New Astronomy, pp. 60-1).

Kepler’s distinction between astronomical and optical sense of the word “still” is important, as this notion that Scripture speaks in the language of ordinary perception becomes very important. It is even echoed in the Chicago Statement on Hermeneutics.

This distinction between “ordinary” and “scientific” perception is real and valid, much as the distinction between “genetic” and “genealogical” ancestry that I’ve brought forward. In fact, we could also say that “genealogical” ancestry is “ordinary,” but “genealogical” is “scientific”, and not spoken of in Scripture. These careful distinctions are made with Kepler in mind. I have great respect for the way he navigated through the early formation of science. He was one of the wise ones.

Galileo makes an argument that appeals to “ordinary” perception too in The Letter to the Duchess, but but in the opposite way. Instead of keeping “ordinary” and “scientific” perception separate, he gives science magisterium over both, and insists that interpretation of Scripture adapt.

I think that in discussions of physical problems we ought to begin not from the authority of scriptural passages but from senseexperiences and necessary demonstrations; for the holy Bible and the phenomena of nature proceed alike from the divine Word the former as the dictate of the Holy Ghost and the latter as the observant executrix of God’s commands. It is necessary for the Bible, in order to be accommodated to the understanding of every man, to speak many things which appear to differ from the absolute truth so far as the bare meaning of the words is concerned. But Nature, on the other hand, is inexorable and immutable; she never transgresses the laws imposed upon her, or cares a whit whether her abstruse reasons and methods of operation are understandable to men. For that reason it appears that nothing physical which senseexperience 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.

Notice that Galileo links ordinary perception with “necessary demonstrations,” which are meant to mean scientific knowledge. He argues that what seems to be true to the science is not to be questioned (much like my discussion partner). No wonder Galileo got himself in trouble. Why would any one think this is a good example to follow? Galileo presents a model that leaves no room for dialogue between science and theology, conflates ordinary and scientific perception. If the scientist sees it, it must be true, and interpretation of Scripture must conform.

So my historian friends, did I understand that correctly? What do you make of this? Why would a Christian chose Galileo as a guide instead of Kepler? @rcohlers, might this be an example of the “two patterns”?

Certainly, the chronology does not match up here. Kepler came first, it seems, then Galileo dropped some bombs. So maybe there is something more complex happening here…


Remarkably, Galileo is a concordist, which is eactly what my partner’s book looked like to me:

Ironically, their ambitious proposal is surprisingly concordist “accepting the reality of genetic evidence supporting a theory of evolution along with an understanding of Adam and Eve that is more in tune with the historical context of Genesis”



Are YECs opposed to concordism more than Evolutionists? Or is Concordism a goblin that triggers the fears and anxieties of Evolutionists more than anyone else?



Whatever the merits of the approaches, Galileo’s seems in keeping with the attitiude that got him into so much trouble - 'tis said that it wasn’t his embracing of Copernicanism that caused trouble so much, as his insistence that the theory was the true account of reality, rather than a good way of “saving the phenomena.” That seems to confim that he had only one way of seeing the world.

Ironically, of course, it was Kepler’s account rather than Galileo’s that best saved the phenomena, but Galileo, for reasons of his own, was unwilling to collaborate with Kepler, or even provide him with a telescope to confirm the findings he had made.


Reading the works of both Kepler and Galileo has to take into account the society, culture, and laws that they lived under. It was not 21st century secular America with freedoms of expression. Kepler and Galileo both faced prosecution even death if branded as a heretics or blasphemers. They had to be very careful and couldn’t be neutral on religion as science inquiry is required to be now They couldn’t isolate themselves in the science. They had to consider the implications of their work on what the all powerful Catholic Church would allow. Kepler and Galileo were freethinkers, great scientists who followed the data that they generated. But in writing about their results were NOT free to fully express themselves under fear of retribution. We must not minimize that when trying to figure out what they were thinking.


Well, they were certainly troublous times, but the fact that the Catholic Copernicus was published through a Lutheran (his only discip0le in his lifetime), and that the Catholic Galileo corresponded with the Calvinist Kepler (who was philosophically a Pythagoran) at all shows that paths could be steered through the dangers.

Kepler is notable for the way that his expressions of praise actually litter his notebooks - his science was par excellence a work of religious devotion. Of course, the neat “religion versus science” division, or even the alternative “religion promoting science”, is rather spoiled by the fact that both Kepler and Galileo were professional astrologers, which neither modern science nor religion is happy with. Here’s one of Galileo’s (of Cosimo):
And one from Kepler:

Which shows the truth of your words:

They were, in fact, members and products of their culture, not just innovators within it.


He was devote Lutheran living in a Catholic city.

This is pseudohistory regarding Kepler. Do you know much about him @Patrick?


Sorry - should have said he was suspected of Calvinist views, which fact limited his freedom of movement.

But we could also add Tycho Brahe, who although apparently less religiously motivated than Kepler, was nevertheless a Lutheran who ended up working in the Impoerial Court Astronomer to the Holy Roman Emperor. Much of Brahe’s personal trouble was political - though to break up the stereotypes again, the suspicion of heresy in his case seems to have been because of suspicion that he was practising alchemy… I think he’s have trouble gaining tenure even today in those circumstances!


Astrology was merely how they paid the bills. No one knew it was false yet. It was not considered superstition.

Yup. As I’ve said, I see him as an important example. If you read the collection of excerpts, and know just some of his story, it is really absurd to think he was writing this way because of fear of reprisal. Kepler had a deep and genuine and worshipful understanding of God through is work, and was careful theologically too. He was Lutheran but disagreed with Luther on doctrine of communion (which is idiosyncratic) and this cause more problems for him in Germany than any of his scientific work.

May be the Lutherans can comment on him too (@Philosurfer, @acuriousmind, @JustAnotherLutheran, @J.E.S).

And don’t forget to read this.


I have read a little about him, certainly not an expert. Tell me some of the psuedohistory, as I am interested in understanding the way he thought and how he navigated the culture of his times.


Off to work, but I will answer more eventually.

The key thing is that the argument that you made was a totally invented historical theory that came latter under the “Conflict Thesis” by Draper This theory (and your argument) has about as much credibility as astrology among historians. It just has no basis in reality. The actual story is more interesting. I wrote about it a bit in this article, though we actually have historians on the boards. They’ll be able to help soon:

Lutheran History

Early Lutherans productively engaged with science. This history is an important model for us all. Luther’s Reformation supported an environment of inquiry, with institutions that enabled early scientists to work, and presses to spread their ideas. Science was controversial in the early days, starting with the Copernican Revolution. Entirely defying “common sense” intuition, heliocentrism imagined the earth hurtled through the heavens around the sun. This counter-intuitive finding entirely reshaped our view of the cosmos, and launched the modern scientific enterprise.

Missing the full story, some focus on just Martin Luther’s offhand comment about geocentrism in 1539. Luther dismissed the new theory of a moving earth in a casual conversation. He commented, “This is what that fellow does who wishes to turn the whole of astronomy upside down. Even in these things that are thrown into disorder I believe the Holy Scriptures, for Joshua commanded the sun to stand still, and not the earth.” On face value, it seems like Luther is blithely dismissing the progress of science. The real history is entirely different.

Luther’s doubts notwithstanding, the Lutheran church never took an official position against Copernican theory. To the contrary, the Lutheran University of Wittenburg played a central role in promoting study of heliocentrism. It was Georg Joachim Rheticus, a professor at the University of Wittenburg, who first published the Copernican theory in 1540 and then encouraged Copernicus to publish a more complete treatment. Later, in 1609, another Lutheran, Johannes Kepler, published his opus Astronomia Nova, a careful geometric analysis that demonstrated that ellipses, not circles, traced the paths of planets, including the earth, around the sun.

So, despite Luther’s Biblically grounded skepticism of Copernican, Lutherans openly considered and embraced heliocentrism without fear of reprisal. This forbearance enabled scientific progress and, more importantly, careful theological reflection. Lutherans prepared the Church as a whole to correctly handle Scripture in light of the new astronomy. Kepler’s introduction to Astronomia Nova includes a careful exegetical analysis of Psalms 104 and Joshua, showing these passages did not put science at odds with the Bible. A faithful reading of the Bible allowed for a true understanding of the cosmos.

In this history, I see a rich heritage to which both Christians and scientists are deeply indebted. As a scientist, I admire Kepler’s obvious and diligent brilliance. As a Christian, I identify with his worshipful devotion to the Creator in his study of creation. I hope I can emulate his careful attention to the theological implications of his work. I also aspire to Luther’s graceful forbearance of those who disagreed with him about. Lutherans granted early scientists the autonomy to understand nature on its own terms, and for this they played a key role in shaping the modern scientific enterprise This is the same tradition that governs science now when my atheist colleagues accept me, a confessing scientist, as one of their own.

A Lutheran voice in science might remember and retell these stories. It might grant scientists the autonomy to study nature on its own terms, and it might carefully prepare the Church for all that science uncovers.


Have a great day. Discover something grand!


Well, of course - which also shows the absurdity of the myth of the secular scientist boldly opposiing the superstition of religion. Nobody yet realised science was supposed to be secular.



But if anything, this “astrology” is part-and-parcel of how Science and Religious views were perceived as a kind of Unity.

For example, Alchemy . . .
[[which most moderns don’t realize was performed with the full expectation that a
righteous practitioner would enjoy the assistance (visible or invisible) of God’s angels!]]
. . . was the synonym for Chemistry, and vice versa.

This can be easily seen by reading the Rosicrucian literature of the early 1600’s


It was only after the French were able to demonstrate that there were distinct procedures available that were more reliable than “alchemical processes” (e.g., praying to an angel for intervention) that the word “chemical” started to become set apart from Alchemy, so that people could more easily determine what kind of “art” was being practiced!


You are missing the point. Astrology is not superstitious before it was disproven. It was only after the Copernican Revolution that it was abandoned. Now, astrology is superstitious, because it has no basis in current knowledge. That means there is a totally different character to trust in astrology before and after the revolution. it is not the same thing.


No I’m not - my comparison is valid. I referred to the “superstition of religion”, not “of astology” (ironically), in comparison to anachronistic condemnation of astrology as superstition.

Interestingly, your (true) point is the same one that Behe made at the Dover trial, for which he has been mocked by all and sundry since, though he was correct.

I wrote some time ago on the scientific foundation of astrology in Mesopotamia despite the absence even of a concept of nature.


I wrote one overview of the heliocentism question here, and a reasonably accurate, if tongue in cheek one here about how religion got us to the moon - the latter of which happens to be one of the few citations of my work in a published book.



Quite right, George. As it happens I also wrote a piece on magic and early science here back in 2014.



Correct, check out the article “Galileo the Emblem Maker” How different is Galielo’s time regarding scientific funding than today’s?

It always is! I’m not a historian, but something to keep in mind between Galileo and Kepler is that the intellectual soil was very different. Kepler and Brahe, working for and against Heliocentric respectively, were working in relatively protestant countries. Luther’s Reformation was started as a reformation of the university curriculum – Before the infamous “Ninety-Five Theses” were nailed to Wittenberg’s door, Luther nailed the “Disputation Against Scholastic Theology” (1517) to the door, calling for a complete overhaul of the university.

Luther had sowed the seeds of educational reform that thinkers such as Melanchthon, Kepler, and Brahe reaped. Galileo had no such luck or champion in Catholic Italy. He had promises from people in high places to protect him and his ideas, but he was instituting educational revolt against Catholic scholasticism during the counter-Reformation.

In hindsight, Galileo was bound to run into problems where the Protestant countries were given a golden opportunity to flourish. And flourish they did! I’ve even found a dissertation suggesting that places such as Oxford and Cambridge were reaching out to little Wittenberg for insight on Copernican astronomy.

The question that I’m curious about is what happened to Wittenberg that it “lost its way” during or following(?) the age of Lutheran scholasticism (post-reformation) and why has the early Reformation Wittenberg with its high view of scripture and love of the Liberal Arts not been able to be replicated on US soil? Most classical Lutheran liberal arts colleges have moved liberal or fundamentalist. The liberal downplays theology as a vestigial organ of educational evolution whereas the fundamentalist tends toward emotionalism and the circling of wagons – both the very opposites of Luther’s and Melancthon’s Wittenberg.


@swamidass @rcohlers @jongarvey

In evaluating the arguments put forth by Kepler and Galileo, we need to keep several facts in mind.

(1) Kepler wrote about this first. Originally he had intended to put his argument about accommodation into the preface to his first book, Mysterium Cosmographicum (1596), but since it was published at Tubingen–where Kepler and Melanchthon had studied (MA) and where M also reformed the curriculum–the theologians disallowed it. Publication had to wait until Kepler got to Catholic Prague, so it appeared in the Astronomia Nova (1609). It isn’t a very long piece, but almost certainly Galileo saw it before writing his letter to Castelli (1613), an earlier version of his much longer Letter to Christina (1615). Galileo likewise used accommodation extensively, and in a similar manner to Kepler, but he went far beyond what Kepler had written, producing IMO the single most important piece on science and the Bible ever written.

(2) Kepler’s intellectual freedom (in Prague) was not at stake. He kept things short and not so sweet, displaying toward those who would toss the Bible in his face the same arrogance that Copernicus had shown in his brief reference to them in the preface to De revolutionibus (1543), which was dedicated to Pope Paul III. Both men just wanted the Bible thumpers to mind their own business. Copernicus advised the Pope to ignore “certain ‘idle talkers’” who are “wholly ignorant of mathematics,” when they “distort the sense of some passage in Holy Writ to suit their purpose.” Kepler advises the devout peasant who ignorantly criticizes him to " to mind his own business and to stay at home and fertilize his own garden," i.e., go pee in your garden, while admiring the beauty of the heavens, the work of the Creator–as Kepler also does. Kepler denies that the Bible is a science book and applies accommodation to its language about nature. He leaves matters there, not developing a sophisticated theory of hermeneutics for passages about nature. He doesn’t need to. The religious concerns pressing down on him are about confessional liberty, not science and the Bible.

(3) Galileo’s situation was almost entirely different. As a devout Catholic in an almost universally Catholic Italy, Galileo isn’t worried about the right to worship God differently. But, he is worried about his intellectual freedom, since the mother of his patron apparently believes that Copernicanism might be heretical–and a Vatican council makes just such a determination the year after he writes his Letter to Christina. Roberto Bellarmino, the chair of that committee, had already responded sternly to a book by a Catholic priest, Foscarini, which argued that the Bible was consistent with Copernicus. Galileo needed to make a lengthy, detailed hermeneutical argument–and he did. As crucial components of that argument, he said these things:

(a) The purpose of the Bible is spiritual, not scientific. It’s the highest authority on the former, but not the latter. Indeed, it would be deleterious for the Bible to lecture ignorant peasants about the real structure of the universe. Since the Earth’s motion is contrary to common sense and ordinary observation, the “rude and unlearned” would be inclined to doubt the truth of the Bible if it addressed such matters in a scientifically accurate manner.

(b) The Bible is written in ordinary human language, aimed at the ordinary person. It’s accommodated to their verbal and conceptual language, regardless of whether they correctly understand nature. This is b/c it’s purpose is to teach salvation, not science.

© Nature, however, is not accommodated at all. It’s written (as he says elsewhere) in the language of mathematics. It is to be understood by “sense experiences and necessary demonstrations,” not from biblical texts. I should add that many of the great Christian scientists from the period Copernicus to Newton agreed with this: they did not believe that the Bible should be used to help us understand nature. Thus, e.g., Boyle almost never cited the Bible in his experimental works, even though he wrote 3/4 of a million words about biblical and theological topics. Indeed, the basic problem of the Bible and science in early modern Europe was mainly solved by keeping the Bible out of the way. That wasn’t equivalent to denying the Bible its proper sphere, or its great importance. It was simply continuing the long practice of methodological naturalism.

(d) Thus, what science says about nature is more likely to be true than the literal sense of Scripture. Since God is the author of both “books,” nature and Scripture, they must not contradict. It is therefore the job of the interpreter to keep in mind that mathematics (the language of nature) is not ambiguous, while human language (the Bible) is often ambiguous. If we use the reliable conclusions of science to help us determine the best interpretation of the Bible, we ensure that we do not create errors in the biblical text by taking it too literally in places where that’s not what God intended.

I do not believe that Kepler’s argument is actually better than Galileo’s. Indeed, if Kepler had seen it (Galileo’s letter wasn’t actually published until after Kepler’s death), I imagine he’d have fully endorsed it. Kepler simply didn’t try to say nearly as much as Galileo needed to say. He was absolutely capable of saying a great deal more about this topic–remember that Kepler began his university career as an MA student in theology, not as a student of astronomy and the arts, and that his life’s goal was to be a theologian. It’s simply that he didn’t need to write the lengthy piece that Galileo was forced by circumstances to write, against his own wishes.