The idea of a continuous struggle between the Church and science became widely known mainly in the nineteenth century. Two authors played a major role: John William Draper and Andrew Dickson White. Their books gave a simple and striking shape to a much more complicated history.

Draper published his book in 1874. He presented advances in knowledge as a struggle against religion, especially Catholicism. White developed his own account, notably in a major work published in 1896. He was also defending his university project against religious criticism.

Their way of telling the story is effective. On one side, brave scientists seek the truth. On the other, religious authorities defend their habits and power. Some events fit this picture well. But many others have to be forgotten or distorted to make the whole story seem consistent.

Since the 1970s, historians have taken a fresh look at these very cases. David Lindberg, Ronald Numbers and Peter Harrison show that the actual relationships involved cooperation, support and tensions. The collection of essays edited by Lindberg and Numbers in 1986 makes this variety particularly clear.^[1]

Several common beliefs do not stand up well to this examination. Christian scholars in the Middle Ages knew that the Earth was round. Universities also carried out dissections. A dissection involves opening a body to study how it is put together. Presenting a ban on dissections as a general policy of the Church is therefore misleading.^[2]

The historian John Heilbron studied the Church's support for astronomy. Astronomy studies the stars and other objects in space, and their movements. According to John Heilbron, for more than six centuries, no other institution gave astronomy greater support. This support was both financial and social. Such a commitment does not fit the idea of constant hostility.^[3]

Peter Harrison adds another difficulty: the ways we now separate science and religion do not exactly match the categories people used in the past. A medieval scholar did not necessarily picture two enemy camps. Giving him our own debates can distort his story, just as changing the meaning of words would make us misunderstand a conversation.

Research that continues over time needs more than intelligent people. It needs places to teach, preserve texts and examine objections. The first European universities developed in a Christian world. Religious authorities helped organise them and protect their freedom.

A university brings teachers and students together for organised studies. In the Middle Ages, these studies were not limited to religious questions. They also covered numbers, shapes, heavenly bodies, medicine and reasoning. Understanding the natural world was therefore part of their everyday work.

The example of Paris helps us understand this practical role. The university received a royal charter in 1200. Rules governing studies followed in 1215. In 1231, Pope Gregory IX strengthened its independence through an official document. This was therefore more than simply tolerating a few isolated scholars.

This independence protected the university's work. Like a school with recognised rules, it depended less on the changing decisions of each local authority. The pope's support therefore helped it gain independence. The history is more surprising than the image of a religious power concerned only with banning things.

Students also learned to present an objection before answering it. They had to distinguish between ideas and justify their conclusions. This practice did not replace modern scientific experiments. But it did develop valuable habits: listening to an argument, spotting a contradiction and not confusing a claim with its proof.

There were limits to this freedom. Theology held an important place in these institutions. Theology seeks to understand God and what the faith teaches. Disagreements could lead to proceedings against teachers. Acknowledging this reality prevents us from replacing a wholly negative myth with a story that has no problems at all.

A heresy is a position that contradicts a truth of faith defined by the Church. Manfred Lütz lists about fifty attempts to put teachers on trial for heresy during the Middle Ages. Most came to nothing.^[4] The overall picture remains one of institutions where people taught, reasoned and debated, with real tensions and fruitful intellectual work.

The Pontifical Academy of Sciences is a scientific institution linked to the pope. Its history began with the Lincei Academy in 1603. Pius XI gave it its current form in 1936. Its eighty members are chosen for their scientific work and do not have to be Catholic. At the Vatican, scientific ability therefore does not depend on religious membership.

The existence of Catholic scientists does not, by itself, prove that every authority always acted well. It does, however, answer an important question. Could faith and research be part of the same life? Several pioneering works show clearly that they could.

Roger Bacon was a member of a religious order who studied light and mathematics, among other subjects. He wrote major works at the request of Pope Clement IV. For him, reasoning needed experience. An explanation can seem convincing and yet fail to describe what we observe.

“Without experience, nothing can be known adequately.”

Roger Bacon, Opus Maius, circa 1267-1268.^[5]

This sentence expresses a simple requirement. To understand nature, repeating an authority or linking ideas together is not enough. We must also look at how things actually happen. Bacon was one of the thinkers who helped develop this approach.

Albertus Magnus, also a member of a Catholic religious order, devoted many works to nature. He studied plants, animals, minerals and heavenly bodies. His work helped establish such research as a legitimate activity within Christian life. Observing creation can be a way of taking what God has made seriously.

Nicolaus Copernicus held a religious position at a church. He defended a hypothesis called heliocentrism. A hypothesis is a proposed explanation that still needs to be examined and tested. Heliocentrism places the Earth among the planets that orbit the Sun.

Copernicus dedicated his major book to Pope Paul III. Religious leaders had encouraged him to publish it, and he faced no action against him during his lifetime. His book appeared in 1543. In 1616, during the Galileo affair, its circulation was suspended pending corrections.^[6] Both of these separate moments matter when we try to understand how his ideas were received.

Nicolaus Steno helped establish geology. Geology studies rocks and the structure of the Earth. His research focused in particular on layers of earth and how they are arranged. He later became a priest. His life reminds us that he did not see the careful study of the ground as incompatible with his faith.

Gregor Mendel worked in his monastery garden. Between 1856 and 1863, he carried out experiments on thousands of pea plants. He studied heredity. This word means the passing of characteristics from parents to their offspring, such as certain visible features in plants.

His results laid the foundations of genetics. This science seeks to understand how these characteristics are passed on. Mendel published his work in 1866, but its importance was not recognised until 1900. It is a telling example: a monastery garden became a place for research whose consequences reached far beyond its walls.^[7]

Lazzaro Spallanzani, also a priest, carried out experiments on broths prepared to eliminate the living things they contained. His experiments disproved the idea that tiny organisms could appear spontaneously in these broths.^[8] His approach combined a precise question, practical experiments and examination of the results.

The Jesuits are members of the religious order called the Society of Jesus. Several studied heavenly bodies and the calendar. Christopher Clavius played a major role in the calendar reform of 1582. Henri Breuil, another priest and scholar, studied ancient cave paintings. These lives show research taking place in several fields, within religious life itself.

The Galileo case remains the strongest objection. In 1633, a Church court condemned a scientist who defended the Earth's motion. This fact must neither be hidden nor treated as an unimportant detail. To understand it, however, let us distinguish what happened from the images added later.

In 1616, Galileo was ordered not to hold or teach heliocentrism. In 1632, he published his Dialogue Concerning the Two Chief World Systems. The book presents a debate but clearly favours Copernicus's system. The authorities considered that he had broken the order he had received.

A personal element made the conflict worse. Pope Urban VIII had been his protector. In the book, some ideas defended by the pope are associated with an unconvincing character. The papal court saw this as an attack. This offence helped harden an affair that already went beyond scientific debate alone.

The interpretation of the Bible also played a central role. Galileo tried to show that the Earth's motion could agree with Scripture. Some theologians, however, thought that certain passages required the Earth to stand still. They treated a question about how heavenly bodies behave as though the faith necessarily determined the answer.

In 1633, Galileo did not yet have decisive physical proof of the Earth's motion. Galileo was right about the Earth's motion, but his explanation of the tides was wrong.^[9] So his arguments were not all beyond question from anyone acting in good faith. This situation explains some of the scientific doubts of the time. It does not justify his condemnation.

In 1633, Galileo was declared vehemently suspect of heresy. The court accused him here of having supported the forbidden doctrine. The decision shows precisely how a scientific question had become mixed up with a religious judgement.

Galileo was not, however, tortured. He was threatened with torture, which remains serious, but the threat was not carried out. Nor did he end his life in a dungeon.

He lived under house arrest, notably at his home in Arcetri. He had to stay in a specified residence and could not travel freely. This punishment limited his freedom while still allowing him to continue working and receive visitors.^[10]

The saying “And yet it moves”, attributed to Galileo after the trial, is not recorded in accounts from the time.^[11] Its fame does not make it authentic. Removing these additions does not mean defending the verdict. It allows us to criticise a real injustice without having to invent others.

Galileo himself had expressed the essential distinction between the biblical text and the human understanding of it:

“If Scripture cannot err, some of its interpreters and commentators can, and in several ways.”

Galileo Galilei, letter to Benedetto Castelli, 1613, quoted by John Paul II.^[12]

On 31 October 1992, John Paul II acknowledged the theologians' mistake in this affair. They had confused Scripture with their own interpretation. They had also brought a question belonging to scientific research into the teaching of the faith. This acknowledgement therefore concerns a specific wrong, rather than a necessary conflict between faith and intelligence.

The lesson remains useful. A religious authority does not become an expert in astronomy because it teaches the faith. Equally, acknowledging its mistake does not prove that the whole faith is false. As in an ordinary discussion, we must examine what was claimed, by whom, with what arguments and in what field.

Witch-hunting provides another image often associated with a Church hostile to reason. People really were persecuted and killed. But to understand who was responsible, we must distinguish popular beliefs, civil authorities and religious institutions. They did not always act in the same way.

Long before the great waves of trials, a religious text called the Canon episcopi treated some accounts of witchcraft as illusions. In particular, it questioned whether extraordinary night-time rides really happened. This doubt matters: Christian authorities could question what the population took for granted.^[13]

That did not prevent all violence. Local fears led to accusations and sometimes attacks by crowds. Catholic leaders also took part in some prosecutions. Saying that the entire Church always rejected them would therefore be just as false as blaming it for every persecution.

The Malleus Maleficarum, written by Heinrich Kramer, belongs to this disturbing history. But this privately written treatise does not sum up the teaching of the whole Church. Historians even debate the authenticity of the university approval letter it includes.^[14] So we cannot treat this work as a joint decision by all Catholic authorities.

The Spanish Inquisition offers a particularly revealing example. After taking part in prosecutions, it began to curb this repression as early as 1526. The historical work reported by Manfred Lütz shows a religious court that was more cautious than other courts.^[15][16] The article on the Spanish Inquisition explores this difference.

How many victims were there? Gustav Henningsen's estimate, reported by Lütz, is about 50,000 across Europe. About 25,000 were in Germany and neighbouring regions. These are historical estimates, not a perfect count. They remain very far from the millions sometimes claimed.^[17]

These deaths remain a tragedy, whatever their exact number. The persecutions affected both Catholic and Protestant territories. In the picture presented by Lütz, pressure came mainly from popular fears and civil courts. Religious courts and theology faculties were often more cautious.^[18] This does not erase the participation of Catholic leaders in some prosecutions.

Georges Lemaître was a Belgian Catholic priest, ordained in 1923. He also became a major researcher in the study of the Universe. His life gives a very practical answer to the idea that we must choose between believing and thinking. He took the requirements of both approaches seriously.

In 1927, he published a study of galaxies moving away from us. Galaxies are large groups of stars. Lemaître established a relationship between their distance and the speed at which they move away. This work helped us understand that the Universe is expanding on a large scale: the distances between galaxies are increasing.

In 1931, Lemaître then proposed the primeval atom hypothesis. He gave this name to the initial state from which the Universe would have developed. This proposal was the forerunner of the model called the Big Bang. This model seeks to describe the physical development of the Universe from a very concentrated initial state.

Yet the decisive point for our subject goes beyond this discovery. Lemaître refused to turn his scientific model immediately into religious proof. He was wary of concordism. Here, concordism means directly matching a scientific theory with a religious teaching, as though one necessarily established the other.

In 1951, Pius XII connected scientific knowledge about the Universe with creation as taught by the faith. Lemaître feared that this connection would make science carry a conclusion it could not establish on its own. He made his concerns known in 1952. The next papal address on the subject no longer referred to the primeval atom.

Why would a priest have these concerns? A physical explanation describes states of the world and how they change. Creation raises the question of the world's very existence. Confusing these questions would make a religious argument depend on a scientific model that might be revised. Lemaître wanted to protect both research and sound religious reasoning.

His faith was not, however, tucked away in a corner of his life, unrelated to his intelligence. He sought the truth along two paths, respecting the requirements of each:

“There were two ways of arriving at the truth. I decided to follow them both.”

Georges Lemaître, interview reported by Duncan Aikman, 1933.^[19]

This attitude avoids two mistakes. It does not ask researchers to confirm a religious interpretation in advance. Nor does it ask them to abandon faith in order to work seriously. Lemaître became president of the Pontifical Academy of Sciences in 1960. His life therefore combined research, priestly life and scientific responsibility at the Vatican.

Questions about the fine-tuning of the laws of the Universe require the same care. Observing galaxies moving away, proposing a model of the Universe and thinking about creation are distinct approaches. They can enter into dialogue. That dialogue becomes stronger when a philosophical conclusion is not presented as the simple result of a calculation.

Lemaître's example helps us understand the Church's texts. These recognise that researchers must study the world using methods suited to their subject. To examine a plant or calculate the motion of a heavenly body, they do not need to draw every answer from a biblical passage.

The Second Vatican Council was an assembly of bishops that set out teachings for the Church. In 1965, its text Gaudium et Spes recognised the legitimate autonomy of research. This autonomy means that natural realities have their own laws, which researchers can discover through their work.

A comparison helps explain this. Knowing a book's author does not remove the need to read its pages. In the same way, believing that God created the world does not remove the need to study it. The existence of a Creator does not do away with natural mechanisms. It gives believers an additional reason to take them seriously.

This autonomy does not mean that the world exists independently of God. Nor does it place research above all moral questions. It recognises a field of work with its own methods. The same text deplores Christian attitudes that failed to recognise this legitimate freedom.^[20]

The question of evolution shows how this distinction works. In this debate, evolution refers in particular to the explanation that the human body came from earlier living forms. In 1950, Pius XII allowed this question to be examined in Humani Generis.^[21] Allowing an investigation does not mean declaring its conclusion definitively established.

The pope also upheld a teaching about the human soul. The soul is spiritual: it cannot be reduced to the material elements that make up our bodies. According to the Catholic faith, it is created directly by God. Research into the origin of the body is therefore not enough to explain everything a person is.

Pius XII also rejected the idea of several independent original couples. Original sin is the sin of our first parents, whose consequences affect all humanity. All human beings descend from the same first parents. This common origin helps explain how the consequences of their sin are passed on to all their descendants.^[22]

In 1996, John Paul II judged the arguments in favour of evolution to be stronger than in the time of Pius XII. He did so in a written message to the Pontifical Academy of Sciences.^[23] This document is authentic, but it is not an encyclical. An encyclical is a teaching letter from the pope. This message does not define any new teaching of faith.

The same message upholds the direct creation of the soul and rejects materialist interpretations of human beings. A materialist interpretation claims to explain the whole of human reality through matter alone. The text therefore does not allow us to conclude that the Church has adopted every interpretation of evolution. The article on the limits of the theory of evolution explores these distinctions.

John Paul II described the relationship between faith and reason more broadly in Fides et Ratio, published in 1998. Reason is our ability to think, compare arguments and seek what is true. Faith does not ask us to give up this ability:

“Faith and reason are like the two wings which enable the human mind to rise to the contemplation of truth.”

John Paul II, Fides et Ratio, prologue.^[24]

Faith and reason are two different means of seeking truth together. Faith does not replace the examination of reasons. Reason is not limited to laboratory experiments.

In 2006, Benedict XVI returned to this idea in an address in Regensburg. He recognised the value of science. But human thought is not limited to the scientific method.^[25]

To understand the underlying disagreement, we need a word: scientism. Scientism claims that only the experimental sciences can give us true knowledge. These sciences test their explanations against observations and experiments. Scientism therefore goes much further than respect for scientific discoveries. It decides in advance that other paths to knowledge cannot reach the truth.

We can understand what makes this position attractive. The sciences produce results that can be checked and impressive technological achievements. Meanwhile, moral or religious discussions sometimes seem endless. Why not place our trust only in what can be observed and measured? The question deserves a real answer.

The first problem is simple. What experiment can prove that only experiments give access to the truth? We can test an explanation of a natural phenomenon. But the claim made by scientism cannot be proved in this way.

The claim made by scientism is therefore philosophical. Philosophy uses reasoning to examine questions about knowledge, reality and human conduct. Scientism itself uses this approach to decide the value of all approaches. It therefore gives its own claim an authority it denies to other philosophical claims.

The biologist Jacques Monod helps us understand another distinction. In Chance and Necessity, he explains that the scientific method rules out the search for a purpose as an explanation of natural phenomena. He also acknowledges that no experiment can demonstrate the absence of all purpose in nature.^[26]

This rule can guide researchers' work without becoming a conclusion about all reality. An instrument is built to detect certain things. Its silence about something else is not enough to prove that this other thing does not exist. In the same way, a method cannot automatically turn its own limits into the boundaries of everything that is true.

Karl Popper offers another useful distinction. It must be possible for a scientific explanation to encounter facts that would prove it wrong. But a statement that cannot be tested in this way is not necessarily meaningless. The boundary of experimental research is not, by itself, the boundary of all reasonable thought.^[27]

Even within scientific research, the conditions under which a method works matter. The article on the limits of carbon-14 dating gives an example. A dating method seeks to determine the age of an object. Understanding what it allows us to say also requires understanding the conditions for using it.

The Church therefore does not ask us to have less confidence in well-conducted experiments. It challenges the move from an effective method to an explanation that must apply to all existence. Rigorous science knows how to define its questions precisely. It benefits from distinguishing its results from additional conclusions a researcher may offer in their own name.

Science describes mechanisms, establishes relationships and makes predictions possible. This knowledge can transform our lives. But knowing how something works does not yet tell us everything about its value. Calculating the energy of an explosion does not, by itself, decide whether causing that explosion would be right.

The philosopher Ludwig Wittgenstein expresses this difference forcefully:

“We feel that even when all possible scientific questions have been answered, the problems of life remain completely untouched.”

Ludwig Wittgenstein, Tractatus Logico-Philosophicus, § 6.52.^[28]

This does not mean devaluing discoveries. It means recognising the question each one answers. A description of our physical mechanisms is not enough to decide how to treat a person. Responsibility, freedom and relationships with others require thought that cannot be reduced to measurement.

The philosopher Jürgen Habermas also warns against reducing human beings in this way. In the analysis reported by Manfred Lütz, he does not challenge the natural sciences. He challenges their extension to the whole of our experience. A physical description does not, by itself, tell us whether we are responsible for our actions.^[29]

Another question arises when we consider the entire Universe. Even if we described its laws perfectly, why would there be a world to which those laws apply? The physicist Stephen Hawking asks this question in a striking phrase:

“What is it that breathes fire into the equations and makes a universe for them to describe?”

Stephen Hawking, A Brief History of Time, chapter 11.^[30]

An equation expresses a mathematical relationship. It helps describe what exists and how it works. But writing a description does not bring the reality it describes into existence. The question of the world's existence therefore goes beyond the question of how it works. The article on why the world exists explores this reasoning further.

Thomas Aquinas distinguishes here between secondary causes and the first cause. Secondary causes are the natural mechanisms that produce effects in the world. The first cause refers to God, who gives existence to the world and these mechanisms. These two explanations therefore do not compete for the same place.^[31]

God does not serve to fill the gaps in scientific knowledge that is still incomplete. Otherwise, every discovery would make part of the religious argument disappear. The question goes deeper: why do mechanisms, regular patterns and the world exist? Describing them ever better does not remove this question.

According to the Catholic faith, the world comes from a Creator who acts with reason. Human intelligence can therefore seek to understand this world. This confidence has also played a historical role.

The sociologist Max Weber, in the analysis reported by Lütz, stresses the importance of habits of life and thought developed in Western Christianity. This does not mean that the Church invented everything on its own. It shows that it helped create some of the conditions favourable to research.^[32]

A convincing answer cannot ask readers to forget uncomfortable facts. The Galileo affair remains a real mistake. Banned books also belong to this history. The Index was a list of works that the Church forbade people to read. Created in 1559, it was abolished in 1966.

Some of its bans affected works that did not deserve this condemnation. Control over books could therefore cause real intellectual harm. Acknowledging these facts helps us understand the limits of human decisions. It also prevents us from confusing the truth of the faith with every judgement made by a religious authority.

Science has also corrected some popular religious interpretations. Manfred Lütz gives the example of the lightning rod. Understanding and controlling lightning challenged the idea that it always directly expressed divine punishment. A widespread belief could thus be corrected without disproving a teaching of faith.^[33]

Other local tensions arose over the study of bodies, rocks or ancient remains. Erasing them would make the history false. But turning them into a general policy would also make the history false. An institution can support an activity while having leaders who, at certain times, misunderstand it.

To judge the whole picture, then, let us look at both sets of facts. There were condemnations and bans. There were also universities, academies, funding and discoveries. An explanation that keeps only one set does not account for what actually happened.

The answer to our opening question is therefore clear. The Church has sometimes hindered researchers and must acknowledge these mistakes. But neither its teaching nor its history as a whole makes it an enemy of science. Its central conviction is that honestly seeking the truth cannot lead to a real conflict with God.

• The story of a never-ending war became widely known in the nineteenth century.
• The Church made major contributions to scientific institutions and work.
• Galileo's condemnation was a real mistake, acknowledged by John Paul II.
• Researchers have legitimate freedom in studying the natural world.
• A scientific theory does not automatically become a teaching of faith.
• Scientism adds a philosophical claim to science that no experiment demonstrates.
• Questions of value, meaning and existence also require the use of reason.

The Catholic faith does not ask us to close our eyes to the world. It invites us to look at it with confidence. This world can be studied, discussed and better understood. Recognising God as Creator does not remove the need for any serious research or turn any human mistake into a truth everyone must accept.

Believers can therefore welcome a discovery without fearing that their whole faith will collapse. They can also question a scientific interpretation without looking down on researchers' work. This history invites us to seek the truth with curiosity and freedom. It also calls for the humility to acknowledge our mistakes.