Friday, April 21, 2023

Evolutionary Psychology Denies Finnis's Metaphysical Natural Law and Confirms Locke's Human Natural Law

Evolution and Human Behavior has published (online, but not yet in print) an article by Carlton Patrick--"Evolution Is the Source, and the Undoing, of Natural Law."  Patrick is a lawyer and a Professor of Legal Studies at the University of Central Florida.  

Previously, I have written about the book that Patrick coauthored with Debra Lieberman--Objection: Disgust, Morality, and the Law (2018).  I said that the main argument of Lieberman and Patrick in that book is a syllogism:  since evolutionary psychology shows that moral emotions like disgust are irrational in ways that are dangerous to society, and since the law should be based on rational principles rather than irrational emotions, disgust (and other moral emotions) should be excluded from the law.  I said that that syllogism is false, because the premise that moral emotions like disgust are utterly irrational is false.  I argued that research in evolutionary moral psychology shows that moral judgment always combines reason and emotion in a complex interaction.  Consequently, moral judgment cannot be properly explained by either a purely emotivist theory or a purely rationalist theory.  In explaining moral judgment in this way as the conjunction of reason and emotion, evolutionary moral psychology confirms the tradition of naturalist moral philosophy that stretches from Aristotle and Thomas Aquinas to David Hume and Adam Smith and then to Charles Darwin and Edward Westermarck. 

Playing off the title of Patrick's new article, I would argue that evolution is the source of natural law as interpreted by Thomas Aquinas and John Locke and the undoing of natural law as interpreted by John Finnis and Robert George.  Patrick's mistake is in assuming that Finnis's (and George's) Kantian distortion of natural law as based on some metaphysical or cosmic order of reason beyond human nature is the correct interpretation of traditional natural law.  He thus ignores the fact that the natural law as understood by people like Aquinas and Locke is rooted in human biological nature in a way that can be confirmed by evolutionary moral psychology.

Patrick begins his article by identifying the proponents of the idea of natural law as including Aristotle, Aquinas, Grotius, Locke, Dworkin, Finnis, and George.  He then singles out Finnis as "the father of the modern natural law argument," who insists that natural law must be founded on "moral objectivity, be it established by God, the universe, or some metaphysical source."  In this way, natural law is based on some "supernatural or metaphysical explanations" that transcend human nature.  For Finnis, this metaphysical order dictates certain "basic goods"--life, health, knowledge, play, friendship, religion, and aesthetic experience--that are "fundamental, underived, irreducible."

Patrick can then argue that evolutionary psychology refutes this metaphysical conception of natural law.  He explains:

". . . when we talk about morality, we are not talking about a cosmic mandate but rather a set of species-wide psychological instincts that are a part of human nature.  These instincts evolved because, over evolutionary time, they helped our ancestors to navigate the highly social world of the evolutionary milieu.  Although there are differing views, most evolutionary scholars agree that the general functions of morality are to avoid, navigate, and resolve conflicts of interest in social interactions" (3).

So, if Finnis's metaphysical interpretation of natural law as founded on a "cosmic mandate" is correct, then evolutionary psychology refutes natural law.  There are two problems here, however.  Patrick simply assumes without proof that Finnis's metaphysical interpretation is correct.  And he fails to consider the possibility that there are better interpretations of natural law as founded on human biological nature that could be supported by evolutionary psychology.

There have been many critics of Finnis's interpretation of natural law--including Henry Veatch, Ralph McInerny, Russell Hittinger, and Anthony Lisska.  Patrick does not mention, must less answer, these critics.  In a series of posts, I have indicated why I agree with the critics.  The primary criticism of Finnis is that his version of natural law is natural law without nature, because he rejects the traditional understanding of natural law as rooted in human nature--in the natural desires or natural inclinations of human beings.  Finnis actually admits this when he dismisses "the rather unhappy term 'natural law.'"  He doesn't like the term "natural law" because it implies that it is rooted in human nature, and that is what he denies (Natural Law and Natural Rights [1980], 35, 198, 280, 374).

Moreover, Patrick does not see that the traditional understanding of natural law is rooted in the principle (as stated by Aristotle, Aquinas, and Locke) that "the good is the desirable," which supports natural law as founded on those natural desires distinctive to human biological nature.  This corresponds to what Patrick calls those "species-wide psychological instincts that are part of human nature," which are studied by evolutionary psychologists.  I have defended this position in Darwinian Natural Right: The Biological Ethics of Human Nature (1998).

Patrick also does not see that natural rights in Locke's state of nature correspond to the natural instincts in what evolutionary psychologists call the "environment of evolutionary adaptedness" (EEA).  I have written about this in various posts (herehere, and here).

This leads me to conclude that while evolutionary psychology denies Finnis's metaphysical natural law, it confirms Locke's human natural law.

Thursday, April 20, 2023

SpaceX's Starship Makes the Case for Lockean Liberal Darwinism in Space

After the first launch attempt on Monday was scrubbed, the launching of Starship today was partially successful.  This was the first attempt at a fully integrated launch of Starship with its Super Heavy booster.  Elon Musk had warned ahead of time that there was a 50/50 chance the Starship would explode on the launch pad.  So, it was a great success when the lift off cleared the launch tower.  The rocket ascended for about four minutes.  But as you can see in the video, if you look at the lower left representation of the booster's engines, it appeared that 5 of the 33 raptor engines in the booster did not fire.  The rocket began spinning erratically.  There was no separation of the booster from the Starship.  Then, there was what SpaceX engineers call a "rapid unscheduled disassembly."  In other words, it blew up!  All of the data from this flight will help for the planning of future flights.  As Musk predicted, it was exciting.

The testing of Starship will continue until SpaceX has shown that both the Starship upper stage and the Super Heavy booster are fully reusable.  Starship must return for a vertical landing, and Super Heavy must return for landing on its launch pad.  That's a big deal because that will drastically reduce the cost of launches into space, which paves the way for space travel that will establish human settlements on the Moon and then Mars.  

From 1970 to 2010, the price of launch to orbit was stable at $10,000 per kilogram (2.2 pounds).   One of the primary reasons for this high price is that the rockets were destroyed in each launch.  Imagine flying a 747 jet, destroying it after one use, and then building a new one for the next flight.  The ticket prices would be high.

Then, beginning in 2010, SpaceX began cutting the price of space launch.  The company introduced partially reusable vehicles.  The Falcon 9 rocket reuses 9 of its 10 engines.  The Falcon Heavy rocket reuses 27 of its 28 engines.  This cut the price of launch from $10,000 per kilogram to $2,000 per kilogram.  Now, if they are successful with Starship becoming a fully reusable heavy lift launch system, the price of a launch to orbit will be reduced to under $500 per kilogram.

The people at NASA and other government space agencies around the world had always assumed that this was impossible.  This all changed with the emergence of an entrepreneurial space race sparked by companies like Musk's SpaceX, Jeff Bezos' Blue Origin, and Richard Branson's Virgin Galactic.  For a libertarian space enthusiast like Robert Zubrin, this shows that human expansion into space--to the Moon, to Mars, and beyond--requires the liberty secured in a free-market society that promotes the freedom of thought for human inventiveness in creating the technology for space travel and exploration (Zubrin 2019, 2022).  

After all, the original space race--between the United States and the Soviet Union--was won by the U.S. when Americans became the first--and the only--people to land human beings on the Moon.  As President John Kennedy indicated in his original announcement of the Apollo program, the aim was to show that a free society can outcompete a tyrannical society in conquering space.  That first space program was planned by politicians and governmental administrators in NASA contracting with private aerospace corporations.  The first crewed Moon landing was achieved in 1969 (Apollo 11).  But after the sixth and last crewed Moon landing in 1972 (Apollo 17), the politicians and administrative bureaucrats lost interest in the early plans for landing human beings on Mars.  In 2008, NASA administrator Michael Griffin said that if the Saturn rocket program that had landed crews on the Moon had been continued, "we would be on Mars today, not writing about it as a subject for 'the next 50 years.'"  That original vision for settling Mars had to be renewed by space entrepreneurs like Musk.  Now, NASA has plans for a Moon to Mars mission that will land human beings on Mars for the first time as a step towards human interplanetary settlement.

But even if this shows that liberty is required for human expansion into space, we might still wonder whether liberty will prevail in the human space settlements on the Moon, Mars, and possibly other moons and planets in the Solar System.  On the one hand, people like Charles Cockell (2013, 2022) have argued that human space societies will be inclined towards tyranny, because everyone in a space society will be totally dependent on their government to provide them artificial life support, and thus those who control the government will be able to tyrannize over the society by threatening to withdraw life support (most importantly, breathable air) from anyone who resists being oppressed.  Under these conditions, liberty can be secured, Cockell contends, only if the right institutions for limiting, dividing, and checking governmental power are established (the sort of constitutional republic established by the American Founders).  

On the other hand, people like Zubrin (2019, 2022) have argued that Cockell's pessimistic fear of the propensity to extraterrestrial tyranny is unjustified, because the only successful human settlements in space will have to be inclined towards liberty.  Zubrin sees at least two main reasons for this.

The first reason is that any successful extraterrestrial society will have to respect individual liberty because only free people with freedom of thought and action can provide the inventive innovation that creates and sustains the technology of artificial life support required for extraterrestrial environments.  There are no natural resources to support human life on Earth or on any other planet.  There are only natural raw materials.  And it is human inventiveness that creates the technology for transforming raw materials into resources.  There are no natural resources on Mars today.  But there will be plenty of resources on Mars once there are lots of resourceful people there to transform raw Martian material into resources for supporting life.

For example, the atmosphere of Mars is very thin, and most of it (95%) is carbon dioxide, with only a trace of oxygen (.174%).  So, a Martian society will need to devise and manage technologies for extracting oxygen.  The carbon dioxide molecules in the atmosphere could be broken up to release the oxygen atoms.  Or, the ice in the polar regions of Mars could be collected, melted, and filtered, and then through the electrolysis of the water, the water molecules could be split into hydrogen and oxygen atoms.  The oxygen could then be provided for breathing, and the hydrogen could be used to make methane fuel.  All of this will require lots of resourceful, inventive people with ideas for how this is to be done.  And these people must have the freedom to discover these ideas and put them to work.  A tyrannical government that would deny this freedom would make it impossible to sustain a society on Mars.

You can see here that Zubrin appeals to the classical liberal argument (of Julian Simon and others) that the resources to support a prosperous human life will always be abundant as long as there are lots of people with good ideas and with the freedom to develop those ideas to solve human problems.  That's why the expansion of human freedom on the Earth over the past two hundred years has created explosive growth in human population and prosperity.  The same will be true for human societies on Mars.

The second reason for why Zubrin thinks Martian societies will have to favor freedom is that only free societies will attract immigrants, and Martian societies will need immigrants to overcome their severe labor shortage.  "From a Darwinian point of view, an extraterrestrial tyranny is an impossibility because that colony would not be able to grow, it would not be able to blossom.  It would be outcompeted for immigrants by ones that offer greater liberty" (Zubrin 2022, 500).

I see this as an extension to Mars of Lockean liberal symbolic niche construction and the evolution cultural group selection with a Lockean open borders immigration policy.


Cockell, Charles. 2013. Extra-Terrestrial Liberty: An Enquiry into the Nature and Causes of Tyrannical Government Beyond the Earth. London: Shoving Leopard.

Cockell, Charles. 2022. Interplanetary Liberty: Building Free Societies in the Cosmos. Oxford: Oxford University Press.

Zubrin, Robert. 2019.  The Case for Space: How the Revolution in Spaceflight Opens Up a Future of Limitless Possibility. Amherst, NY: Prometheus Books.

Zubrin, Robert. 2022.  "The Case for Space is Liberty."  In The Institutions of Extraterrestrial Liberty, ed. Charles Cockell, 497-504.  Oxford: Oxford University Press.

Sunday, April 16, 2023

On the Way to Liberty on Mars? The First Test Flight of SpaceX's "Starship"


                                                  Animation of a SpaceX Starship Mission to Mars

A few months ago, in my post on "The Astrobiology of Lockean Liberty on Mars," I wrote about Elon Mush's plan for flying human beings to Mars on SpaceX's "Starship."  Starship could lift as much as 250 tons and accommodate 100 people on a trip to Mars.

Before the first trip to Mars, Starship will take NASA astronauts to land on the Moon, which has not been done in over 50 years.  In a few years, Starship could be used to take passengers on flights around the Earth, traveling from any place on Earth to any destination (such as London to Sydney) in less than an hour.

Many tests of the Starship spacecraft have failed, as indicated by the dramatic videos of the explosions.  But about two years ago, Starship successfully launched and then returned for a soft landing.  That's the critical point because it's the reusability of this spacecraft that is crucial for making space travel affordable.  Imagine how expensive commercial air travel would be if every passenger jet could be used for only one flight.

Tomorrow (April 17, beginning at 7:15 am Central Time), SpaceX plans to launch the Starship spacecraft on top of its Super Heavy rocket booster.  At the SpaceX website and at YouTube, you can watch this live.

The launch pad is at SpaceX's Starbase complex in South Texas, 20 miles north of Brownsville.  The test flight will last about 1 1/2 hours.  The hope is that it will reach orbit but without a full orbit of the Earth.  About three minutes after launch, the booster will separate and fall into the Gulf of Mexico.  The spacecraft will continue eastward, passing over the Atlantic, Indian, and Pacific oceans before falling into the sea near Hawaii.  Although nothing will be saved from this test flight, eventually both the spacecraft and the booster will be reusable.

Musk has said that there is only a 50% chance that the Starship will reach orbit.  But he has a whole fleet of Starships under construction, and he predicts that there is an 80% chance that one of these will attain orbit by the end of this year.

Musk's SpaceX is one example (along with Jeff Bezos' Blue Origin and others) of the stunning success of spacefaring entrepreneurs doing what NASA and other governmental space programs have failed to achieve. In 2022, SpaceX had 61 successful launches of its Falcon rockets with commercial payloads.  As of today, SpaceX has more than 3,300 of its Starlink communications satellites in operation.  SpaceX also has contracts with NASA for transporting astronauts and material to the International Space Station.

Musk has also participated in the discussions over how the human settlements on Mars could be designed to promote liberty and avoid tyranny.  That's the question that I want to think about.

Sunday, April 09, 2023

Pope John Paul II on Darwinian Evolution and the Spiritual Soul: Did He Resolve the Reason/Revelation Debate?

Easter Sunday should prompt us to think about the miracle of resurrection in the reason/revelation debate.  Can the Biblical revelation of the resurrection of Jesus and the resurrection of human beings to eternal life in Heaven or Hell be defended against the charge from natural reason that this is an irrational belief that denies what we know about natural human mortality?  Does the Darwinian evolutionary science of human life deny the truth of this religious belief in immortality?  Or can we see that the scientific truth of the evolution of the mortal human body and the religious truth of the immortal human soul belong to two separate spheres of human knowledge--science and faith--and that neither can refute the other?  Does the unique dignity of human personhood as set apart from and above other animal life depend on the special divine creation of human beings ("in the image of God") as having a spiritual soul that is immortal?  Can evolutionary science explain this religious belief in the spirituality and immortality of the soul?  Or does this belief show a human experience of revelation that cannot be explained by evolutionary science?  Does this show an irreconcilable conflict between the Bible and Darwinian evolution?

In the previous posts, we have seen how Galileo tried to reconcile the apparent conflict between the Bible and the science of astronomy by saying that "the intention of the Holy Spirit is to teach us how one goes to Heaven and not how heaven goes."  And we have seen how Pope John Paul II accepted Galileo's solution to the problem.  

But then the Pope had to show how this solution could apply to the apparent conflict between Biblical creationism and Darwinian evolution.  If the Bible teaches us "how to go to Heaven" by teaching us that our souls can be resurrected to eternal life in Heaven, can that Biblical teaching about the immortality of the human soul be reconciled with the scientific teaching that human life originated through the same natural evolutionary process that has shaped the mortal existence of all animal life?

In 1996, the Pope delivered an Address to the Pontifical Academy of Sciences in a celebration of the sixtieth anniversary of the Academy's refoundation.  This was called a "refoundation" because the Academy claims that its founding by Pope Pius XI in 1936 was actually a renewal of the Academy of the Lynxes founded in Florence in 1603 by Federico Cesi, which was one of the earliest modern learned academy for the promotion of research in natural science and mathematics.  They were called "lynxes" because the luminescence of the lynx's reflective eyes was associated with enlightened vision into the world.  Remarkably, its most prominent member was Galileo.

The Pope's speech in 1996 was on "The Origins and Early Evolution of Life."  He began by noting that the "Magisterium of the Church" had already made two pronouncements on this topic.  ("Magisterium" refers to the teaching authority of the Church, particularly in its authoritative teaching about how the Holy Spirit interprets the Bible.)  The first pronouncement was the encyclical Humani Generis (1950) from Pope Pius XII.  The second was Pope John Paul's own speech to the Academy in 1992 rehabilitating Galileo.

We might say that having rehabilitated Galileo, the Pope now had to rehabilitate Darwin.  These cases do differ, however, in that while Galileo was formally condemned by the Inquisition, and his Dialogue was put on the Index of Prohibited Books, Darwin had never been formally condemned by the Church, and his books were never prohibited.  And yet we do know now that beginning at the end of the nineteenth century, some Church authorities secretly condemned some priests for teaching that evolution was compatible with the Bible--for example, John Zahm's book Evolution and Dogma (1896).  But there was never a public condemnation.  This suggests that the Church authorities had learned their lesson with the Galileo affair, and so they were reluctant to make the same mistake with Darwin.

In Humani Generis, Pope Pius XII had made two claims about the theory of human evolution.  First, he claimed that this theory "has not been fully proved," and therefore it was only a "hypothesis" or a "conjectural opinion" that might someday be disproven (secs. 5, 35).  Notice how similar this is to the Inquisition's assertion that the Copernican system was only a "hypothesis" that was opposed to the "hypothesis" of the Ptolemaic system.

The second claim was that even if the Church took seriously the hypothesis of evolution "in as far as it enquires into the origin of the human body as coming from pre-existent and living matter," the Church must affirm that "the Catholic faith obliges us to hold that souls are immediately created by God" (sec. 36).

Pope John Paul disagreed with the first point but agreed with the second.  Against the first point, the Pope saw that now the theory of evolution is "more than a hypothesis":  "Today, almost half a century after the publication of the Encyclical, new knowledge has led to the recognition that the theory of evolution is more than a hypothesis.  It is indeed remarkable tht this theory has been progressively accepted by researchers, following a series of discoveries in various fields of knowledge.  The convergence, neither sought nor fabricated, of the results of work that was conducted independently is in itself a significant argument in favor of this theory" (sec. 4).

The phrase "more than a hypothesis" is the correct English translation of the original French version of the Pope's speech.  The first English version published by the Vatican mistakenly translated this as "more than one hypothesis in the theory of evolution."  The Vatican's news service corrected this mistake a few weeks after issuing the first version.

That evolution was "more than a hypothesis" because it was a well-confirmed theory is the message that that was proclaimed in the front-page newspaper stories around the world: the Catholic Church now accepts the truth of Darwinian evolution!  Many scientists welcomed this news.  But many fundamentalist creationists and proponents of "intelligent design theory" vehemently criticized the Pope for adopting theistic evolution and rejecting the literal reading of the Bible's account of God's creation of human beings.

There was much less public attention given to Pope John Paul's crucial point of agreement with Pope Pius XII, which seemingly weakened the Church's endorsement of the Darwinian theory of human evolution.  Pope John Paul agreed that even if Darwinian science explains the natural evolution of the human body without any miraculous intervention by God, the Christian must believe that the human soul requires special divine creation: "if the human body takes its origin from pre-existent living matter, the spiritual soul is immediately created by God."  Consequently, "theories of evolution which, in accordance with the philosophies inspiring them, consider the mind as emerging from the forces of living matter, or as a mere epiphenomenon of this matter, are incompatible with the truth about man.  Nor are they able to ground the dignity of the person."  The human soul requires an "ontological leap" or "ontological discontinuity" that runs counter to the "physical continuity" assumed in evolutionary science (secs. 5-6).  (Here the Pope seemed to adopt John Zahm's thinking, which originally was developed by George Jackson Mivart.)

The Pope went on to explain:

". . . Consideration of the method used in the various branches of knowledge makes it possible to reconcile two points of view which would seem irreconcilable.  The sciences of observation describe and measure the multiple manifestations of life with increasing precision and correlate them with the timeline.  The moment of transition to the spiritual cannot be the object of this kind of observation, which nevertheless can discover at the experimental level a series of very valuable signs indicating what is specific to the human being.  But the experience of metaphysical knowledge, of self-awareness and self-reflection, of moral conscience, freedom, or again, of aesthetic and religious experience, falls within the competence of philosophical analysis and reflection, while theology brings out its ultimate meaning according to the Creator's plans" (sec. 6).

There are six problems with the Pope's assertions here.  The first one is that while he speaks of "the moment of transition to the spiritual," he does not precisely locate that moment of transition.  Did it happen at some point in hominid evolution?  Did God miraculously intervene in the transition from Homo erectus to Homo sapiens to implant a spiritual soul in the human brain that could then be passed on by genetic inheritance to all human beings?  Or does God have to intervene in the embryological development of each human individual to implant a soul?  In some previous posts, I have considered the medieval debate over whether the human soul can be transmitted through semen.  Does the Pope believe that God must infuse a supernatural soul at some point in a woman's pregnancy?

The second problem is that while the Pope seems to say that the divine creation of the soul is not open to empirical observation, he also says there are "valuable signs" that might be observable.  Could paleontologists look for these "valuable signs" in the record of hominid evolution?  Or could embryologists look for signs of ensoulment in the process of gestation?

A third problem is that the Pope says nothing about the possibility that evolutionary scientists could explain the evolutionary emergence of the soul in the brain.  Why not say that the human soul is uniquely human because of the 16 billion neurons in the human cerebral cortex?  And why couldn't God have used the natural evolutionary process to create that increase in neurons over a critical threshold that produced the humanly unique mental capacities of human beings?  Or is the Pope saying that God was unable or unwilling to work through natural evolution in this way?

A fourth problem is that the Pope identifies religious belief as an expression of the spiritual soul, but he does not consider how evolutionary psychology could explain that natural human propensity to religious belief, perhaps as one manifestation of the uniquely human evolved capacity for symbolism--for imagining symbolic worlds that might include Heaven and Hell.

The fifth problem for the Pope is that he claims to exercise the Teaching Authority (the Magisterium) of the Church in interpreting Biblical revelation as guided by the Holy Spirit.  But it seems that the Holy Spirit has failed to guide Christians to agreement about that Biblical revelation as it applies to the creation/evolution debate and other issues concerning the relationship between science and religion.  After all, the members of the Inquisition in 1633 thought they were being guided by the Holy Spirit in condemning Galileo; but then the Pope in 1992 thought the Holy Spirit had revealed to him that they were mistaken.

In John, chapter 17, Jesus prays to God that all believers will be as one, that they will come to complete unity, "so that the world may believe that you have sent me."  It seems that Christians were to give witness to the truth of revelation by showing their agreement about that revelation as guided by the Holy Spirit.  But the Holy Spirit has failed to do that.  When devout Christians strive to reach agreement in how they interpret the meaning of the Bible as applied to modern science, they fail.

The final problem for the Pope is that he seems to separate science and religion as belonging to two different realms of knowledge or experience that never intersect.  Indeed, Stephen Jay Gould interpreted the Pope's speech in 1996 as supporting Gould's idea of "nonoverlapping magisteria" (NOMA): the magisterium of science teaches us about the factual reality of the natural universe, while the magisterium of religion teaches us about the transcendent reality of the supernatural realm, and neither should interfere with the other.  But I agree with Richard Dawkins in his argument that these two realms must inevitably intersect, because "religion makes existence claims, and this means scientific claims."  Dawkins observes: "A universe with a supernatural presence would be a fundamentally and qualitatively different kind of universe from one without."  And so, in a universe in which God supernaturally creates spiritual souls and miraculously implants those souls into human brains should manifest observable evidence of those "ontological leaps."  

For that reason, there is a long history of debating the evidence for the resurrection of Jesus and the resurrection of human souls.  I do concede, however, that such debates between reason and revelation might be unresolvable in that neither side can truly refute the other.


Dawkins, Richard. 1997. "Obscurantism to the Rescue." Quarterly Review of Biology 72 (December): 397-99.

Gould, Stephen Jay. 1997. "Nonoverlapping Magisteria." Natural History 106 (March): 16-22, 60-62.

John Paul II. 1997.  "Message to the Pontifical Academy of Sciences." Quarterly Review of Biology 72 (December): 381-83.

Pontifical Academy of Sciences. 2004. The Four-Hundredth Anniversary of the Pontifical Academy of Sciences, 1603-2003.  Vatican City: The Pontifical Academy of Sciences.

Saturday, April 08, 2023

How Pope John Paul II Resolved the Galileo Affair

In three speeches addressed to the Pontifical Academy of Sciences (in 1979, 1992, and 1996), Pope John Paul II restated Galileo's reasoning about science and biblical religion, while acknowledging explicitly that this showed that Galileo was right, and the Church wrong, in 1633.  In these speeches, the Pope made three claims about the character of the Reason/Revelation debate in a modern Lockean liberal social order.

The first claim is that the Church must allow this Reason/Revelation debate to be conducted on the basis of freedom--religious freedom and scientific freedom--so that neither side in the debate can coercively suppress or punish the other.

The second claim is that the Church must concede to Reason that the Revelation of the Bible must be interpreted as compatible with natural science, so that the Bible is seen not as a textbook about the natural world but a book about how to achieve the supernatural salvation of the human soul in Heaven, which surpasses the natural human understanding expressed in natural science.

The third claim is that to support this supernatural teaching of the soul's eternal salvation, the Church must teach that the Darwinian science of the soul's emergent evolution in the brain fails to account for the reality of the spiritual soul that can only be explained as the product of God's miraculous creation, so on this point Revelation must prevail over Reason.  

In 1979, the Pontifical Academy of Sciences met to commemorate the centennial of Albert Einstein's birth.  Pope John Paul delivered a speech with the title "Deep Harmony Which Unites the Truths of Science with the Truths of Faith."

He explained that science and religion are harmonious as long as both are free.  "Just as religion demands religious freedom, so science rightly claims freedom of research" (sec. 5).  To support this liberal idea of religious liberty and scientific liberty as authoritative for the Catholic Church, the Pope cited the statement Gaudium et spes from the Second Vatican Council in 1965, which recognized "the legitimate autonomy of culture and especially of the sciences" (sec. 59).  In a remark that echoed the title of Galileo's Dialogue Concerning the Two Chief World Systems, the Pope immediately applied this principle of freedom to the case of Galileo: "The Church, filled with admiration for the genius of the great scientist in whom the imprint of the creative spirit is veiled, without intervening in any way with a judgment which it does not fall upon her to pass on the doctrine concerning the great systems of the universe, proposes the latter, however, to the reflection of theologians to discover the harmony existing between scientific truth and revealed truth" (sec. 5).

The Pope recognized that both Galileo and Einstein characterize the modern scientific era.  But unlike Einstein, Galileo "had to suffer a great deal--we cannot conceal the fact--at the hands of men and organisms of the Church."  The Pope again cited Gaudium et spes:  "we cannot but deplore certain habits of mind, which are sometimes found too among Christians, which do not sufficiently attend to the rightful independence of science and which, from the arguments and controversies they spark, lead many minds to conclude that faith and science are mutually opposed" (sec. 36).  Although Galileo's name is not mentioned in this passage, the Pope suggested that the reference to Galileo was clear in the note to this sentence, which cited Pio Paschini's book on the life and works of Galileo, which had been published by the Pontifical Academy of Sciences (sec. 6).

The Pope was silent about the controversy within the Church over Paschini's book (Finocchiaro 2005, 318-37).  To mark the tricentennial of Galileo's death in 1942, the Pontifical Academy of Sciences had commissioned Paschini (a priest who taught Church history) in 1941 to write a book on Galileo's life and work.  But when Paschini submitted his book in 1945 to Church authorities for approval, they refused to permit its publication because they thought the book was too favorable to Galileo.  The book was finally published in 1964, after Paschini's death, only after the book had been edited to remove some of the more favorable comments about Galileo and the criticisms of the Church's condemnation of Galileo.

At the Second Vatican Council in 1964, some of the delegates wanted the Council to formally rehabilitate Galileo and acknowledge the Church's error in condemning him.  But some of the delegates resisted this.  In one of the early versions of Gaudium et spes, there was language stating that the condemnation of Galileo was an error that should never be repeated.  But some of the delegates objected to this language.  They finally reached a compromise as suggested in some of the abbreviated notes on the discussion: "Galilei.--Inopportune to speak of this in the document.--Let us not force the Church to say: I made a mistake.  The matter should be judged in the context of the time.  In Paschini's work everything is said in the true light" (Finocchiaro 2005, 329).  As approved on December 7, 1965, Gaudium et spes showed the compromise.  There was a passage about the legitimate "regret" that some Christians did not respect "the rightful autonomy of science," but Galileo's name was not mentioned in the text.  There was, however, a cryptic footnote to the passage that said:  "Cf. Msgr. Pio Paschini, Vita e opere di Galileo Galilei, 2 volumes, Vatican Press (1964)."  A careful reader who knew something about the controversy around Paschini's book could see this as a veiled confession that the Church had erred in Galileo's case.

Expressing his desire "to go beyond this stand taken by the Council," the Pope said that he hoped that theologians, scholars, and historians would "study the Galileo case more deeply" and dispel the mistrust that impedes the "fruitful concord between science and faith."  He then quoted remarks by Galileo in three of his writings that showed this harmony of science and faith.  In his Letter to Castelli, Galileo spoke of the "two books"--Holy Scripture and nature--that both manifest the divine Word.  In his Starry Messenger, he said that in his discoveries made through his telescope, he had been "enlightened by divine grace," which the Pope saw as "Galileo's confession of divine illumination."  And in his Letter to the Grand Duchess Christina, Galileo explained that to reconcile the Bible and science, we must go beyond the literal meaning of the Bible, which can contradict the truths of science, to see that the real meaning of the Bible must be interpreted in whatever way renders it compatible with what science discovers about the natural world.  

Here we see the Pope agreeing with Galileo that biblical revelation must be interpreted to conform to whatever scientific reason correctly teaches about nature.  And in that sense, reason takes priority over revelation.  But at the same time, the Pope says that in the Pontifical Academy of Sciences, "believing and non-believing scientists collaborate, concurring in the search for scientific truth and in respect of the beliefs of others," which suggests that scientific truth can neither confirm nor deny religious truth.

To satisfy his hope that people would reexamine the Galileo case, Pope John Paul II announced in 1981 the appointment of a Vatican commission to study the Galileo affair (Finocchiaro 2005, 343-53).  This commission was subdivided into four subcommittees to study the exegetical, cultural, scientific-epistemological, and historical-juridical issues arising from Galileo's trial and punishment.  They sponsored a series of scholarly conferences and the publication of some books.

In 1992, at a plenary session of the Academy of Sciences, Pope John Paul heard and accepted the Vatican Commission's final report on the Galileo affair.  At this session of the Academy, there was a second topic for discussion--the nature of complexity as studied in mathematics, physics, chemistry, and biology.  In his speech--"Faith Can Never Conflict with Reason"--the Pope said that the Inquisition's trial and punishment of Galileo was a mistake, and this was widely publicized around the world, including a front-page story in the New York Times, as an apology from the Church for what it had done to Galileo 350 years earlier.

In the middle of this speech, the Pope repeated his arguments from 1979 for agreeing with Galileo's biblical hermeneutics--rejecting the literal interpretation of the Bible when this would contradict what natural science had discovered about the natural world--and for seeing how this supported the harmony of science and faith.

In the beginning and end of his speech, he observed that "from the Galileo affair we can learn a lesson which remains valid in relation to similar situations which occur today and which may occur in the future."  He suggested that those "similar situations" were likely to arise not from astronomy, physics, or mathematics, but from "relatively new disciplines such as biology and biogenetics," particularly related to the theme of "the emergence of complexity."  "Let us think, for example, of the working out of new theories at the scientific level in order to take account of the emergence of living beings.  In a correct method, one could not interpret them immediately and in the exclusive framework of science.  In particular, when it is a question of the living being which is man, and of his brain, it cannot be said that these theories of themselves constitute an affirmation or a denial of the spiritual soul, or that they provide a proof of the doctrine of creation, or that, on the contrary, they render it useless."

Here, I think, the Pope was pointing ahead to the problem that he would take up a few years later, in 1996, which I call the Darwin Affair, and which turns on the question of whether Darwinian biology can explain the natural emergent evolution of the human soul in the brain, or whether the human soul arises from a supernatural transcendence of nature that can be known only by religious faith, and whether this belief in the supernatural spirituality of the soul is essential to the Bible's teaching about "how one goes to Heaven."

That's the topic for my next post.

Thursday, April 06, 2023

The Galileo Affair, 1633-1893


From 1616 to 1624, Galileo obeyed the "Special Injunction" that he had received from Cardinal Bellarmine in 1616--that Galileo would "abandon completely" the Copernican view of the Universe and "henceforth not to hold, teach, or defend it in any way whatsoever, either orally or in writing."  But then in 1624, he began to write the book that would be published early in 1632 under the title Dialogue on the Two Chief World Systems, Ptolemaic and Copernican.  That book provoked the Inquisition in 1633 into proceedings against Galileo that would force him to sign a document of abjuration and to be imprisoned (under house arrest in his villa outside Florence) for the rest of life, until his death in 1642.

In 1623, the old pope died, and Cardinal Maffeo Barberini was elected Pope Urban VIII.  Urban was a well-educated Florentine, who admired Galileo, and who had helped to keep the Inquisition from publicly condemning Galileo and Copernicanism in 1616.  Urban's position had been, and continued to be, that as long as the Copernican system was treated as a mere "hypothesis" that could not be absolutely demonstrated to be true, then it should not be considered a heretical denial of the Bible.  He insisted that if Copernicanism were affirmed to be a truth about nature, that would deny God's omnipotence by denying God's arbitrary power to design the cosmos in any way He wished.

In the spring of 1624, Galileo went to Rome and stayed there for six weeks to pay his respects to the new pope.  He met weekly with Urban, and the two had friendly conversations that led Galileo to think that the Pope might be his supporter.  But when Urban read the Dialogue in July of 1632, he felt betrayed because he saw in the book, beneath the shallow pretense of treating the Copernican system as a mere hypothesis, a clear defense of that system as a probable truth based on the best evidence and demonstrative arguments.

Galileo had written his book as an imagined dialogue with three interlocutors.  Salviati defended the Pythagorean and Copernican system.  Simplicio spoke for the Aristotelian and Ptolemaic system.  Sagredo acted as an educated gentleman who commented on the debate.  Like a Platonic dialogue, Galileo did not speak in his own name, but the reader could see that Salviati was his spokesman; and the reader could also see that Salviati was allowed to make the stronger arguments.  It was also a good joke that Simplicio's name suggested he was a "simpleton."

It should be noted that while these three characters in the Dialogue discuss the cosmological, astronomical, physical, and philosophical aspects of Copernicanism, they say nothing about the biblical issues.

It is also noteworthy that Galileo has Salviati argue that he, not Simplicio, is the true Aristotelian philosopher, because Aristotle would have accepted the modern scientific evidence for the Copernican system.  Consider this passage:

"SALV.  Whenever you wish to reconcile what your senses show you with the soundest teachings of Aristotle, you will have no trouble at all.  Does not Aristotle say that become of the great distance, celestial matters cannot be treated very definitely?"

"SIMP.  He does say so, quite clearly."

"SALV.  Does he not also declare that what sensible experience shows ought to be preferred over any argument, even one that seems to be extremely well founded?  And does he not say this positively and without a bit of hesitation?"

"SIMP.  He does."

"SALV.  Then of the two propositions, both of them Aristotelian doctrines, the second--which says it is necessary to prefer the senses over arguments--is a more solid and definite doctrine than the other, which holds the heavens to be unalterable.  Therefore, it is better Aristotelian philosophy to say, 'Heaven is alterable because my senses tell me so,' than to say, 'Heaven is unalterable because Aristotle was so persuaded by reasoning,'  Add to this that we possess a better basis for reasoning about celestial things than Aristotle did.  He admitted such perceptions to be very difficult for him by reason of the distance from his senses, and conceded that one whose senses could better represent them would be able to philosophize about them with more certainty.  Now we, thanks to the telescope, have brought the heavens thirty or forty times closer to us than they were for Aristotle, so that we can discern many things in them that he could not see, among other things these sunspots, which were absolutely invisible to him.  Therefore, we can treat of the heavens and the sun more confidently than Aristotle could" (Galileo 2001, 63-64).

One could see this as Galileo agreeing with my argument that Aristotle doubted the truth of his cosmology, because he saw that the fundamental premises of his reasoning about cosmology were not based on observational evidence, since in studying astronomical phenomena, "there is so little evidence available to our sense experience," and therefore his cosmological astronomy was based on ancestral myths about the divinity of the heavens that were believed only by faith.  Consequently, Aristotle would have been open to the observational evidence provided by Galileo's telescope that supported modern astronomy.

I have written about Hobbes's suggestion that the "vain philosophy" of the Aristotelian Scholastic theologians was based on what Aristotle knew to be "false Philosophy," which Aristotle professed to believe only because of his "fearing the fate of Socrates."  This suggests the possibility that Aristotle's secret teaching in his natural science supports Galileo's modern science in challenging the medieval model of the cosmos.

This also suggests that Leo Strauss was wrong in claiming that Aristotelian natural right requires an Aristotelian cosmic teleology that has been refuted by modern science.  Aristotle saw that natural right could be rooted in the immanent teleology of his biological science that was better grounded in sense experience than his cosmology.  And, as I have argued, Aristotle's biological teleology was confirmed by Charles Darwin's evolutionary biology.

Moreover, Galileo suggested that Aristotle would have accepted the empirical evidence for modern biology--for example, the anatomical evidence for the primacy of the brain (rather than the heart) in the human nervous system as the natural biological ground for the human mind (Galileo 2001, 124-26).

Galileo observed that people like Simplicio who identify their Aristotelian philosophy with repeating what is said in Aristotle's texts without considering the new empirical evidence for modern science are not really philosophers, because they are actually "historians or memory experts" rather than philosophers (Galileo 2001, 130-31).


In the summer of 1632, the Pope ordered a ban on the recently published
, and he commissioned a special committee of three people to study the Dialogue and send him a report with their assessment of it.  In September, their report concluded that Galileo had violated the orders of the Inquisition and the Pope, because "many times in the work there is a lack of and deviation from hypothesis, either by asserting absolutely the earth's motion and the sun's immobility, or by characterizing the supporting arguments as demonstrative and necessary, or by treating the negative side as impossible" (Finocchiaro 1989, 221).  The Pope then submitted the case to the Inquisition in Rome, and Galileo was summoned to Rome to stand trial.

In April and May of 1633, Galileo sat for four depositions before the Inquisition, in which he answered questions.  In his first deposition, he said that he had understood that Cardinal Bellarmine's special injunction in 1616 meant that he could hold Copernicus's opinion only "suppositionally" (ex suppositione) or "hypothetically" (ex hypothesi), because to hold it "absolutely" true would be repugnant to the Bible; and he claimed that in the Dialogue, he had done that because he had never advocated Copernicanism in absolute terms.

But then the Inquisition received commissioned reports from people who had read the Dialogue and offered their assessments of what Galileo had done in that book.  The report from Melchior Inchofer was meticulous in quoting many passages in the book where Galileo "teaches, defends, and holds the opinion of the earth's motion" (Finocchiaro 1989, 262-70).

In his second deposition, Galileo said that he had reread his book to see if "against my purest intention, through my oversight," he had conveyed the impression to his readers that he was defending Copernicanism as simply true.  He explained:

". . . Now, I freely confess that it appeared to me in several places to be written in such a way that a reader, not aware of my intention, would have reason to form the opinion that the arguments for the false side, which I intended to confute, were so stated as to be capable of convincing because of their strength, rather than being easy to answer. . . . I resorted to that of the natural gratification everyone feels for his own subtleties and for showing himself to be cleverer than the average man, by finding ingenious and apparent considerations of probability even in favor of false propositions. . . . My error then was, and I confess it, one of vain ambition, pure ignorance, and inadvertance. . . ." (Finocchiaro 1989, 277-78).

Galileo lied.  And the members of the Inquisition knew that he had lied to them.  Any attentive reader of the Dialogue would know that Galileo was lying here because nothing in that book suggested that Galileo "intended to confute" the "arguments for the false side"--for the Ptolemaic system.  The sentence of the Inquisition against Galileo in June included the remark that "we did not think you had said the whole truth about your intention" (Finocchiaro 1989, 290).  Galileo felt compelled to lie to avoid the severest punishment.  

In the sentence of punishment, Galileo was declared to be "vehemently suspected of heresy."  This was a technical term because it was one of three religious crimes, in descending order of seriousness: formal heresy, vehement suspicion of heresy, and slight suspicion of heresy.

The punishment had four parts.  Galileo was ordered in front of the Inquisition to "abjure, curse, and detest" his errors and heresies.  It was also ordered that his book Dialogue would be prohibited and placed on the Church's Index of Prohibited Books.  He was condemned to "formal imprisonment in this Holy Office at our pleasure."  And he was ordered to recite the seven penitential Psalms (Psalms 6, 32, 38, 51, 102, 130, and 143) once a week for the next three years (Finocchiaro 1989, 291).

Galileo presented his abjuration on June 22:

". . . I have been judged vehemently suspected of heresy, namely of having held and believed that the sun is the center of the world and motionless and the earth is not the center and moves."

"Therefore, desiring to remove from the minds of Your Eminence and every faithful Christian this vehement suspicion, rightly conceived against me, with a sincere heart and unfeigned faith I abjure, curse, and detest the above-mentioned errors and heresies, and in general each and every other error, heresy, and sect contrary to the Holy Church; and I swear that in the future I will never again say or assert, orally or in writing, anything which might cause a similar suspicion about me; on the contrary, if I should come to know any heretic or anyone suspected of heresy, I will denounce him to this Holy Office, or to the Inquisitor or Ordinary of the place where I happen to be."

"Furthermore, I swear and promise to comply with and observe completely all the penances which have been or will be imposed upon me by this Holy Office; and should I fail to keep any of these promises and oaths, which God forbid, I submit myself to all the penalties and punishments imposed and promulgated by the sacred canons and other particular and general laws against similar delinquents.  So help me God and these Holy Gospels of His, which I touch with my hands" (Finocchiaro 1989, 292).

Galileo was seventy years old.  He would live another nine years, dying in 1642.  During those nine years, he saw the beginning of what came to be called the "Galileo Affair"--the debate over the Inquisition's punishment of Galileo that has lasted for over 350 years.  Ultimately, this has been a debate about the character of modern natural science and philosophy in its denial of the medieval theological model of the cosmos, and about whether a liberal social order can safely allow philosophic freedom of thought in the public discussion of such questions.


Acting under the express orders of Pope Urban VIII, in the summer of 1633, the Roman Inquisition sent copies of the sentence against Galileo and his abjuration to all papal nuncios (the Pope's ecclesiastical diplomats) in Europe and all local inquisitors in Italy, with orders to publicize them.  This was the first and only time that the Inquisition has so widely publicized an inquisitorial trial.  This was the Pope's warning to Catholics not to question the authority of the Church and his presentation of himself as a defender of the faith in the Counter-Reformation's attack on Protestant heretics and on all those who thought they could interpret the Bible for themselves rather than following the interpretation forced upon them by the Church.

Since the Inquisition publicized only the sentence against Galileo and his abjuration without releasing the entire proceedings, there was not enough information to determine clearly exactly what punishment Galileo had suffered.  The sentence says: "we deemed it necessary to proceed against you by a rigorous examination."  Many people assumed that the Inquisition's "rigorous examination" included torture.  Later, when the trial proceedings were released in 1867, people saw in Galileo's fourth deposition that "he was told to tell the truth, otherwise one would have recourse to torture."  But now historians generally agree that while Galileo was threatened with torture, he was not actually tortured (Finocchiaro 2009).  The official manuals for the Inquisition included procedures for torture.  But there is no evidence that Galileo was made to suffer any kind of physical torture.

The sentence against Galileo declares: "We condemn you to formal imprisonment in this Holy Office at our pleasure."  This refers to the jail at the Inquisition palace in Rome.  But when the correspondence surrounding Galileo's trial and punishment was published in 1774, it became clear that Galileo was probably never confined in a jail.  While Galileo was in Rome for his trial, the Inquisition permitted him to lodge either in the Tuscan embassy or in the prosecutor's six-room apartment.  After he was sentenced, Galileo was permitted to travel to Siena and live under house arrest at the residence of the archbishop, a friend of Galileo's.  In December of 1633, Galileo was allowed to go to his own villa in Arcetri, near Florence, where he remained under house arrest until his death.

So, the old story that Galileo was tortured and imprisoned is mistaken (Finocchino 2009).  But still being under house arrest for nine years was a serious punishment.  And that his Dialogue remained on the Index of Prohibited Books was also an important part of his punishment, although the book was published in parts of Europe that were free from the Inquisition.

And what about the order that Galileo recite the seven penitential Psalms once a week for three years?  There's no clear evidence that he performed this act of penance.  In October of 1633, Galileo's daughter--who had become the cloistered nun Maria Celeste--wrote to him and said that she would take upon herself the obligation to recite the seven psalms one time each week "to relieve you of this care" (Sobel 2011, 312-15).  This is strange because it was not legally or theologically possible to substitute one person's penance for that of another.

Far from showing penance for what he had done, Galileo often insisted in his correspondence after 1633 that he had been "unjustly condemned" (Finocchiaro 2005, 59-60).  He complained of this injustice to the many prominent people from around Europe who visited him in Arcetri.  These visitors included people like Thomas Hobbes and John Milton.  This provoked a debate that has lasted for over 350 years as to whether Galileo should be seen as a persecuted martyr of philosophy and science, and how this might illustrate the conflict between science and religion or reason and revelation.  Many people have compared Galileo's trial and punishment to that of Socrates.

Milton might have been the first person to present Galileo's case as showing the need for protecting philosophic freedom of thought and expression against the coercive enforcement of religious and intellectual orthodoxy.  Milton had visited Galileo in 1639.  Then, in 1644, he published his Areopagitica, in which he argued against a censorship law enacted by the English Parliament in 1643, which prohibited books from being published without legal licensing by governmental censors.  

Milton's primary argument for "the liberty of unlicensed printing" is that licensing manifests the tyrannical evil of the Catholic Inquisition--"this project of licencing crept out of the Inquisition" (Milton 1999, 8).  He observes:

". . . I could recount what I have seen and heard in other Countries, where this kind of inquisition tyrannizes; when I have sat among their lerned men, for that honor I had, and bin counted happy to be born in such a place of Philosophic freedom, as they suppos'd England was, while themselvs did nothing but bemoan the servil condition into which lerning amongst them was brought; that this was it which had dampt the glory of Idalian wits; that nothing had bin there writt'n now these many years but flattery and fustian.  There it was that I found and visited the famous Galileo grown old, a prisner to the Inquisition, for thinking in Astronomy otherwise then the Franciscan and Dominican licencers thought. . . ." (Milton 1999, 31-32).

One can see what's at issue here by contrasting Milton's scorn for the Inquisition as denying "philosophic freedom" and Robert Bellarmine's advocacy of the Inquisition as showing the spiritual authority of the Pope to enforce Christian orthodoxy and punish heretics.  As I have already indicated, Bellarmine was one of the most influential theologians of the Counter-Reformation Catholic Church and a member of the Inquisition both when it attacked Copernicanism in 1616 and when it sentenced Giordano Bruno to be burned at the stake in 1600 for theological and scientific heresies.

While many Catholic theologians had said that the pope had the "fullness of power" (plenitudo potestatis) in temporal matters, Bellarmine claimed that the pope had only "indirect power" (potestas indirecta) in temporal matters.  Political rulers have their own autonomous power grounded in natural and divine law that is separated from the spiritual authority of the pope.  But still, Bellarmine explained, there is a point where the temporal and spiritual realms merge.  The pope must advance humanity's ultimate end, which is the eternal salvation of souls in Heaven.  To achieve this end, the pope can order political sovereigns to punish heretics and pagans--even to the point of torturing and killing them--when they deny those orthodox Christian doctrines necessary for eternal salvation (Bellarmine 2012, 87-120)  

Against those Christians who asserted that political governments should secure religious and intellectual liberty as a way to promote peace among Catholics and Protestants, Bellarmine insisted that the pope must promote the punishment and even killing of Protestants who deny the authority of the Catholic Church to interpret the Bible for them.  Against the argument that the New Testament Christians did not use secular political power to persecute heretics, Bellarmine claimed that when Constantine gained control of the western part of the Roman Empire in 312 and converted to Christianity, this fulfilled the prophecy of Psalm 2:10-11--"Therefore, you kings, be wise; be warned, you rulers of the earth.  Serve the Lord with fear and celebrate his rule with trembling" (Bellarmine 2012, 119-20).  But one can easily see that Psalm 2 celebrates the coronation of a new king in ancient Israel as a theocratic ruler, which differs from the teaching in the New Testament.  Bellarmine cannot show that the New Testament supports his defense of theocracy.

As I have argued previously, libertarian Protestants like Milton, Roger Williams, John Locke, and C. S. Lewis have noted that in contrast to the Mosaic theocracy of the Old Testament, the New Testament churches were voluntary organizations that did not use violent coercion to compel belief in an established orthodoxy.  In that way, the New Testament supports the classical liberal principles of religious liberty and toleration.

Over the past three hundred years, the popes and the Catholic Church have gradually moved towards these liberal principles as the only grounds for resolving the Galileo Affair by avoiding the apparent conflict between the Bible and science.  

As we have seen, the "vehement suspicion of heresy" for which Galileo was condemned was based on two ideas.  The first was Galileo's scientific claim that the Earth revolves daily on its own axis and revolves yearly around the Sun.  The second was his hermeneutical claim that the Bible was not an authority for natural science but an authority only on questions of faith and morals.

The Church began to accept the scientific claim in 1757 when the Congregation of the Index withdrew the decree that prohibited all books teaching the Earth's motion, although Galileo's Dialogue and a few other books remained on the list of prohibited books.  Then, in 1822, the Congregation of the Holy Office (the Inquisition) allowed the Catholic astronomer Joseph Settele could teach the motion of the Earth as an established fact.  Finally, in 1835, the new edition of the Catholic Index of Prohibited Books for the first time omitted the Dialogue.  Oddly, however, there was no public statement from the Church about this.

Then, in 1893, the Church began to accept Galileo's hermeneutical claim about biblical interpretation in the light of science.  In Pope Leo XIII's encyclical Providentissimus Deus, without ever naming Galileo, Leo adopted Galileo's view for how to interpret the Bible so that it is always harmonious with natural science; and Leo employed the same reasoning that Galileo had advanced in his Letter to the Grand Duchess Christina.

The correct interpretation of God's revelation through the Bible must be guided by the Holy Spirit.  But we must see that Augustine was correct in teaching that the Holy Spirit did not intend to teach human beings scientific truths about the visible universe that were not necessary for salvation.  The Bible's accounts of the natural world use figurative language that would have been familiar to people in biblical times, figurative language that should not be taken literally as a statement of scientific fact.  Quoting the same passages from Augustine quoted by Galileo, Leo argued that when scientists demonstrate some truth about the natural world, Christians must interpret the Bible as compatible with that scientific truth.  As Augustine said, "whatever they can really demonstrate . . . . we must show to be capable of reconciliation with our Scripture."

Leo also employed Galileo's metaphor of the "two books":  God speaks through the Book of the Bible and through the Book of Nature, and these two truths cannot contradict; so that whatever scientists discover about the Book of Nature must determine our reading of the Bible so that it harmonizes with this natural truth.

In my next post, I will show how Pope John Paul II followed in the path taken by Pope Leo to finally resolve the Galileo Affair--and also the Darwin Affair--and showed how the Church could allow for the Reason/Revelation debate to be conducted in a Lockean liberal social order.


Bellarmine, Robert. 2012. On Temporal and Spiritual Authority.  Indianapolis: Liberty Fund.

Finocchiaro, Maurice. 1989. The Galileo Affair: A Documentary History. Berkeley: University of California Press.

Finocchiaro, Maurice. 2005.  Retrying Galileo, 1633-1992. Berkeley: University of California Press.

Finocchiaro, Maurice. 2009. "Myth 8. That Galileo Was Imprisoned and Tortured for Advocating Copernicanism." In Ronald L. Numbers, ed., Galileo Goes to Jail, and Other Myths About Science and Religion, 68-78.  Cambridge: Harvard University Press.

Galilei, Galileo. 2001. Dialogue Concerning the Two Chief Systems. Trans. Stillman Drake. New York: The Modern Library.

Milton, John. Areopagitica, and Other Political Writings of John Milton. Indianapolis: Liberty Fund.

Sobel, Dava. 2011. Galileo's Daughter: A Historical Memoir of Science, Faith, and Love. New York: Bloomsbury.

Saturday, April 01, 2023

Galileo on the Harmony Between Biblical Faith and Scientific Reason: Separating "How One Goes to Heaven" From "How Heaven Goes"?

Recently, an article in the New York Times noted that 30 asteroids have been officially named after Jesuit astronomers.  Last month, three new ones were named after three Jesuit priests:  565184 Janusz for the Rev. Robert Janusz, a polish priest and physicist, 551878 Stoeger for the Rev. William R. Stoeger (1943-2014), an American priest, and 562971 Johannhagen named for the Rev. Johann Georg Hagen (1847-1930), an Austrian American, who is said in the naming citation to have "devised several ingenious experiments at the Vatican to demonstrate the rotation of the Earth, directly confirming the theories of Copernicus and Galileo."  All three of these men have worked in the Specola Vaticana (the Vatican Observatory), just off the papal gardens at Castel Gandolfo, close to Rome.  The Vatican Observatory was first established by Pope Leo XIII in 1891 to support advances in the science of astronomy.

This must surprise many of us who have been taught the story about how the Catholic Church's Inquisition in 1633 punished Galileo Galilei with imprisonment for teaching that the Earth rotates and moves around the Sun and thus committed the heresy of denying the Bible, which seems to teach that the Earth is unmoved at the center of the cosmos, with the Moon, the Sun, and the planets moving around the Earth.

Actually, Galileo showed how there need be no conflict between Biblical faith and scientific reason, as long as one sees that the Bible teaches us "how one goes to Heaven" but not "how heaven goes."  Remarkably, the Catholic Church--particularly under the leadership of Pope John Paul II in 1992--has accepted this teaching of Galileo and admitted that the punishment of Galileo by the Catholic Inquisition was wrong.  The Church has also adopted this teaching as supporting the liberal principles of religious liberty and scientific liberty.  This has allowed the Church to accept the scientific truth not only of Galilean astronomy but also of Darwinian evolution as consistent with the transcendent salvational truth of the Bible.  The official Catholic acceptance of Darwinian evolution came in 1996 with a statement by Pope John Paul II.  Protestants (like Francis Collins and Deborah Haarsma) have followed the lead of the Catholic Church in accepting "theistic evolution" or "evolutionary creation" as compatible with both Biblical truth and scientific truth.  What we see here is that even if the teaching of Galileo does not completely resolve the tension between Reason and Revelation, it does at least leave it open to free debate in a free society.


In 1543, Nicolaus Copernicus published his book On the Revolutions of the Heavenly Spheres, in which he updated the ancient Greek idea (of Pythagoras and others) that the Earth moves by rotating on its axis daily and by revolving around the Sun once a year.  This was rejected by the proponents of the Ptolemaic geocentric system with a stationary Earth at the center of the cosmos and the Sun and the planets revolving around the Earth.  The argument of Copernicus was mostly hypothetical:  if the Earth were in motion around the Sun, then the observed phenomena in the sky would result.  But Copernicus could not present enough empirical evidence to make his idea persuasive.

There were four kinds of objections to the Copernican system (see Finocchiaro 1989, 16-25).  The first was that it was epistemologically absurd because it denied our direct sensory experience of the world.  Throughout our lives, all of us perceive that the Earth is at rest, while the rest of the cosmos moves around the Earth.  Every day we see that the Sun rises in the east and sets in the west.  Of course, we know that our senses are sometimes deceived: a straight stick half immersed in water appears bent.  But we easily correct such perceptual illusions.  By contrast, it's hard to see how we could correct our perception of the Earth being at rest.  That would be such a radical deception of our senses that we would lose all confidence in our senses as a guide to truth.

The second objection was that the Copernican system was empirically false because it predicted some astronomical consequences that were not observed.  For example, if Copernicus was right, then the Earth must be a planet, the third planet circling the Sun, with physical properties like the other planets.  But according to the medieval model of the cosmos, the Earth differed in its elemental properties from the heavenly bodies.  The heavenly bodies were made of the element ether, which was weightless, luminous, and changeless, while the Earth was made of rocks, water, and air, which were (positively or negatively) weighted, dark, and changeable.  Also, if Copernicus was right, then the planet Venus should show phases similar to the Moon, and the planet Mars should show differing apparent brightness and size since Mars and the Earth revolve around the Sun at different rates.  Before the telescope, this kind of objection seemed to be empirically supported.

The third objection to the Copernican system was that it was physically impossible because it violated some of the fundamental principles of physics as it was known at the time.  That the Earth could rotate on its axis or revolve around the Sun seemed physically impossible because the natural motion of earthly bodies (rocks and water) was to move in a straight line to the center of the Earth.  There were three types of natural motion (as opposed to forced or violent motion): ether (the element of the heavenly bodies) moved eternally in a circular motion around the center of the cosmos; the elements air and fire moved in a straight motion away from the center of the cosmos; and the elements earth and water moved in straight motion to the center of the cosmos.  Every simple element could have one and only one natural motion.  Answering this objection required developing a new science of physics with new laws of motion, such as the law of inertia, the law of gravitational force, and the law of conservation of momentum.

The fourth objection to the Copernican system was that it was theologically heretical because it contradicted the literal meaning of the Bible and the unanimous biblical interpretations of the early Church Fathers.  For example, in Joshua 10: 12-13, the Bible tells us: "Then spoke Joshua to the Lord in the day when the Lord delivered up the Amorites before the children of Israel, and he said in the sight of Israel, 'Sun stand thou still upon Gibeon; and thou, Moon, in the valley of Ajalon.' And the sun stood still, and the moon stayed, until the people had avenged themselves upon their enemies."  Protestants agreed with this biblical objection because of their literal interpretation of the Bible.  Catholics agreed with this biblical literalism, but they also agreed with the appeal to the Church Fathers because Catholics saw God's revelation through the work of the Holy Spirit in guiding both the authors of the Bible and the traditional theology of the Church.

Galileo tried to answer all four objections, but the biblical objection was the hardest to overcome, and that led to his condemnation by the Catholic Church's Inquisition.


In the fall of 1609, Galileo built the first astronomically useful telescope, and he used it to study the night sky.  In 1610, in his book The Starry Messenger, he published some of his discoveries: that the Moon, like the Earth, has a rough, rocky, and nonluminous surface, and that the planet Jupiter has at least four moons, and thus constitutes its own miniature planetary system.  Later he published other discoveries: that the planet Venus shows phases similar to the Moon; that the planet Mars shows large changes in brightness and apparent size; and that there are dark spots on the Sun that move in such a way as to suggest that the Sun rotates on its axis once a month.  In his published writings, Galileo did not explicitly indicate how this was evidence for the Copernican heliocentric system; but in his private correspondence, he was open about this.

In response to Galileo's new evidence for the Copernican system, the conservative supporters of the Ptolemaic system began to rely on biblical arguments based on biblical passages that apparently teach that the Sun revolves around the Earth, as in Joshua 10:12-13.  In December of 1613, Galileo responded to these biblical arguments in a letter to his friend Benedetto Castelli.  Although it was not published, this letter was widely copied and circulated.

Employing the traditional theological metaphor of God's "two books"--that God reveals His truth both in the books of the Holy Scripture as dictated by the Holy Spirit and in the book of Nature as governed by the laws of nature given by God that can be known by human reason--Galileo claimed that these two truths of the Bible and nature can never contradict each other (Galileo 1989a).  Whatever the Holy Spirit teaches in the Bible must be consistent with whatever scientists discover to be true about nature by sensory experience and necessary demonstration.  

But sometimes the literal meaning of the words of the Bible can contradict the findings of natural science.  And then one must see that the literal interpretation of the Bible is an error.  As guided by the Holy Spirit, the authors of the Bible often had to adapt what they said to the understanding of common people.  And so, for example, there are many biblical passages that "attribute to God feet, hands, and eyes, as well as bodily and human feelings like anger, regret, hate, and sometimes even forgetfulness of things past and ignorance of future ones," because common people tend to have such anthropomorphic conceptions of God; but surely to take this as a literally true account of God would be blasphemous (Galileo 1989a, 50). Similarly, the Bible might speak of the Sun revolving around the Earth, because common people would be unable to comprehend the truth of the Earth's moving and the Sun standing still.  The intention of the Holy Spirit was not to teach natural science but to teach what was required for salvation; and so that salvific teaching was true, while much of what might be said about the natural world could be false if interpreted literally.

This Letter to Castelli provoked attacks on Galileo from some traditionalist Christians, and particularly some Dominican friars in Florence.  In December of 1614, Tommasco Caccini preached a Sunday sermon in a church in Florence arguing that Galileo was a heretic in contradicting the Bible.  In February of 1615, another Dominican--Niccolo Lorini--filed a written complaint against Galileo with the Inquisition in Rome, and he enclosed a copy of Galileo's letter to Castelli as evidence of heresy.  In March of 1615, Caccini appeared before the Roman Inquisition for a deposition, in which he claimed that Galileo's Copernican teaching denied the literal sense of the Bible as supported by the unanimous interpretation of the Church Fathers.

In response to these charges, Galileo wrote a series of essays in 1615, of which the most important was his Letter to the Grand Duchess Christina which elaborated the arguments from his letter to Castelli.  Today, these arguments from the Letter to Christina have been adopted by many Catholic and Protestant scientists as supporting their belief that biblical faith and natural science must be in harmony (see, for example, Block and Freeman 2019).

In the Letter to Christina, Galileo (1989b) continued to employ the "two books" metaphor and to argue that the harmony between those two books depends on seeing that the true meaning of the Bible is not the pure literal meaning.  He continued to use the Bible's anthropomorphic descriptions of God (as having hands, feet, eyes, and bodily sensations and feelings) as illustrating how the biblical authors accommodated their writing to the mistaken understanding of common people.  And he continued to argue that the primary purpose of the Bible is teaching the way to salvation, which does not require any true scientific teaching about the natural world.  (I have written previously about how Charles Darwin also employed the "two books" metaphor to support the compatibility of biblical faith and evolutionary science.)

Galileo captured the gist of his reasoning in a clever aphorism that has been one of Galileo's most often quoted remarks: "the intention of the Holy Spirit is to teach us how one goes to heaven and not how heaven goes" (Galileo 1989b, 96).

This plays off of the ambiguity in the word "heaven."  The Italian word cielo, the Latin word caelum, and the English word "heaven" all have a double meaning.  According to the Oxford English Dictionary, the primary meaning of "heaven" is "the expanse in which the sun, moon, and stars are seen, (esp. in earlier use) regarded as having the appearance of a vast vault arched over the earth; the sky, the firmament."  The secondary meaning is "the abode of God and of the angels and persons who enjoy God's presence, traditionally regarded as being beyond the sky; the final abode of the redeemed after their life on earth; a state or condition of being or living with God after death; everlasting life.  Opposed to hell."

One interpretation of Galileo's Copernican Revolution as conveyed in his separation of "how one goes to heaven" from "how heaven goes" is to say that he separated heaven (as God's abode and the abode of the redeemed in the afterlife of immortality that can be known only by faith) from the sky (as the expanse of astronomical bodies and space that can known by natural science); and while these two realms of two kinds of truth must be separated, they are not contradictory; and the biblical believer can see them as two different expressions of one truth--God.

In making this argument for the harmony of biblical truth and scientific truth in the Letter to Christina, Galileo appealed to the authority of St. Augustine, which countered the charge that he was denying the teachings of the Church Fathers.  He quoted from Augustine's On the Literal Interpretation of Genesis as saying that "whenever the experts of this world can truly demonstrate something about natural phenomena, we should show it not to be contrary to our Scripture" (Augustine 1999, 1.21).  The Bible must be interpreted in such a way as to be consistent with human knowledge of the natural world, including the movements of the sun, the moon, and the planets.  After all, "it frequently happens that even non-Christians will have knowledge of this sort in a way that they can substantiate with scientific arguments or experiments" (1.19).  The authors of the Bible "knew about the shape of the sky whatever may be the truth of the matter.  But the Holy Spirit who was speaking through them did not wish to teach people about such things which would contribute nothing to their salvation" (II.20).  (Notice how this remark by Augustine is echoed in Galileo's quip about separating "how one goes to heaven" from "how heaven goes.")  The intention of the Holy Spirit was to teach people through the Bible not about the natural truth of the natural world but about the supernatural truth of salvation through the doctrines of "the resurrection of the dead, the hope of eternal life, and the kingdom of Heaven" (Augustine 1999, 1.19; Galileo 1989b, 112).

There are, however, at least three problems in Galileo's reasoning in his Letter to Christina--in his assumption that the divine reality of Heaven does not depend on any particular scientific conception of the cosmos, in his dismissal of the anthropomorphic depictions of God in the Bible, and in his claim that the Holy Spirit has clearly conveyed the way to salvation in Heaven through the revelation of the Bible in a manner that does not deny the truth of natural science.

The first problem is that since the medieval cosmic model (such as Dante depicted in The Divine Comedy) located Heaven in the Empyrean realm and Hell below the surface of the Earth, Galileo's scientific denial of that model denied the reality of Heaven and Hell.  Remarkably, Galileo's first public lecture as a young man was about the mathematical geography of Hell in Dante's Inferno, as if Hell were a real subterranean place deep in the Earth (Heilbron 2010, 28-33).  But then in the Letter to Christiana, he suggested that the way to the afterlife taught in the Bible belongs to the supernatural world known by religious faith as opposed to the natural world known by scientific reason (Galileo 1989b, 101). 

Must faith and science therefore be totally separated?  Or is it possible, as I have suggested in various posts, for science to study the natural history, the cultural history, and the individual psychology of religious beliefs in Heavenimmortalitythe afterlife, and the existence of God?

The second problem in Galileo's Letter to Christina is his assumption that the anthropomorphic image of God in the Bible as having a body is so absurdly blasphemous that this proves that the literal meaning of the Bible is often a mistaken interpretation.  This is dubious for two reasons.  While the Bible is full of passages describing God's body, nowhere does the Bible say that the literal meaning of these passages must not be taken seriously.  After all, from the beginning of the Bible, God is said to have created man in His own image and likeness, which is to say that God was in the image and likeness of man.  And in the New Testament, it is clearly taught that Jesus, the Son of God, has a perfect human body--that He is God incarnate ("in the flesh").

Recently, Francesca Stavrakopoulou has written a wonderful book--God: An Anatomy--in which she goes through the Bible to find accounts of God's body, from his head to his hands, feet, and genitals.  She points out, however, that when the ancient Jewish and Christian theologians came under the influence of Platonic Greek philosophy, they began to identify the God of the Bible with Platonic abstractions about the Divine as timeless, changeless, and immaterial.  God became a transcendent, invisible, and incorporeal being that was a distorted refraction of the original biblical image of God as an embodied being made in our own image.

The third problem in Galileo's Letter to Christina is his dubious assumption that the Holy Spirit will guide us to the correct interpretation of biblical revelation, and that this correctly interpreted teaching about the truths of faith will not conflict with the truths of science.  Previously, I have argued that the Holy Spirit has failed to convey that correct interpretation of biblical revelation that would resolve the creation/evolution debate among Christian believers.  Similarly, it seems that the Holy Spirit failed to persuade the Roman Inquisition that Galileo was correct in interpreting the Bible as compatible with Copernican astronomy.

Throughout 1615, the Roman Inquisition commissioned reports and took depositions pertaining to the charge that the Copernican system was heretical, and that Galileo was a heretic for teaching this.  In December of 1615, Galileo left his home in Florence to travel to Rome to try to clear his name and prevent the Inquisition from condemning Copernicanism.  He lodged at the Tuscan embassy in Rome for six months.  Since 1610, Galileo had been the philosopher and chief mathematician of the Grand Duke of Tuscany.

The Inquisition asked a group of theologians to prepare a report on Copernicanism.  On February 24, 1616, they submitted a report that concluded that the Copernican teaching was "foolish and absurd in philosophy, and formally heretical since it explicitly contradicts in many places the sense of Holy Scripture, according to the literal meaning of the words and according to the common interpretation and understanding of the Holy Fathers and the doctors of theology" (Finocchiaro 1989, 146).

On the following day, the Inquisition asked Cardinal Robert Bellarmine (a Jesuit priest and probably the most influential Catholic churchman of his time) to meet with Galileo and demand that he agree to abandon his Copernican opinions, and that if he did not acquiesce, he would be imprisoned.

The next day, Bellarmine met with Galileo and gave him a "special injunction . . . to abandon completely . . . the opinion that the sun stands still at the center of the world and the earth moves, and henceforth not to hold, teach, or defend it in any way whatever, either orally or in writing; otherwise the Holy Office [the Inquisition] would start proceedings against him.  The same Galileo acquiesced in this injunction and promised to obey" (Finocchiaro 1989, 147-48).

A few days later, Bellarmine reported to the Inquisition that the Congregation of the Index of Prohibited Books would decree that Copernicus's book On the Revolutions of the Heavenly Spheres would be suspended until it could be corrected.  Only a few lines of the book were changed.  Copernicus's book had been permitted for over 70 years.  But now it became the first book devoted entirely to science to be condemned, even if only temporarily until it was slightly revised, by the Congregation of the Index.  Anyone but Galileo could discuss the corrected book, as long as they called it only a hypothesis.

On March 12, Galileo reported to the Tuscan Secretary of State that he had met with Pope Paul V for three-quarters of an hour, and that the Pope had received him warmly and even told him that he should feel safe as long as the Pope lived.

Galileo began to receive letters from friends in Pisa and Venice reporting rumors that Galileo had been personally put on trial and condemned by the Inquisition.  To silence these rumors, Galileo asked Cardinal Bellarmine to write a statement certifying that he had not been formally condemned by the Inquisition.  Bellarmine wrote:

". . . we say that the above-mentioned Galileo has not abjured in our hands, or in the hands of others here in Rome, or anywhere else that we know, any opinion or doctrine of his; nor has he received any penances, salutary or otherwise.  On the contrary, he has only been notified of the declaration made by the Holy Father and published by the Sacred Congregation of the Index, whose content is that the doctrine attributed to Copernicus (that the earth moves around the sun and the sun stands at the center of the world without moving from east to west) is contrary to Holy Scripture and therefore cannot be defended or held" (Finocchiaro 1989, 153).

We see here that Galileo both won and lost his battle.  He won by escaping personal public condemnation by the Church.  But he lost the intellectual and theological debate over whether Copernican science was compatible with biblical faith.

In 1633, however, he would lose the whole battle when the Inquisition condemned him to abjuration, penance, and imprisonment for teaching the truth of Copernican science.  And yet, eventually, by 1992, he would be vindicated by the Church.

In my next post, I will look at the intellectual history of the "Galileo Affair," and I will suggest that its resolution--among both Catholic and Protestant Christians--followed a similar pattern for the "Darwin Affair" (the debate over whether Darwinian evolution is compatible with the Bible), so that in both cases Reason triumphed over Revelation among Christians, because they agreed that they needed to look to scientific reason to correct the Holy Spirit's interpretation of the Bible, so that they could see how Copernican astronomy and Darwinian biology do not deny their religious belief in the transcendent destiny of their souls; and therefore they could accept freedom of thought for scientists and philosophers in a Lockean liberal social order as posing no threat to their Christian pilgrimage in the world.


Augustine, Saint. 1999. The Literal Meaning of Genesis.  In Augustine, On Genesis, trans. Edmund Hill, 159-581. Hyde Park, NY: New City Press.

Block, David, and Kenneth Freeman. 2019. God and Galileo: What a 400-Year-Old Letter Teaches Us About Faith and Science. Wheaton, IL: Crossway.

Finocchiaro, Maurice, ed. 1989. The Galileo Affair: A Documentary History. Berkeley: University of California Press.

Galileo Galilei. 1989a. Letter to Castelli. In Maurice Finocchiaro, ed., The Galileo Affair: A Documentary History, 49-54. Berkeley: University of California Press.

Galileo Galilei. 1989b.  Letter to the Grand Duchess Christina.  In Maurice Finocchiaro, ed., The Galileo Affair: A Documentary History, 87-118.  Berkeley: University of California Press.

Heilbron, J. L.  2010. Galileo. Oxford: Oxford University Press.

Stavrakopoulou, Francesca. 2022. God: An Anatomy. New York: Knopf.