November 2019: Apologetics

Of Faith and Evolution: Discovering Truth

Is Catholicism anti-science? This is a question that is all too often poorly answered in the public domain. Some authors promote the view that the Church is anti-science, without offering any real evidence. In recent decades, there has been a growing dialogue between science and religion. This dialogue is often complex, and some expertise is needed to understand both the scientific content and the corresponding theological perspectives. A certain intellectual humility and an eye for subtlety is required in order to avoid sweeping statements concerning one or the other. Nevertheless, there is considerable evidence that the Church’s perspective is open minded and highly cognisant of both the limitations and the possibilities of science.

There are many areas of science that impact on faith, but perhaps the most often cited is that of evolutionary biology, which utilises highly sophisticated techniques to unravel the history of life on earth, and which encompasses subjects such as genetics, speciation (exploring species boundaries), palaeontology, embryology, physiology, animal behaviour and psychology. As is often the case when new subject specialisms arise, those working in the area can tend to overstretch the significance of their findings. Within the subject of evolutionary biology, significant disagreement still exists with regard to the level at which selection pressures operate, namely, whether selection works primarily at the level of genes and individuals, or operates between groups of individuals.

Many people are familiar with the somewhat misleading phrase ‘survival of the fittest,’ which seeks to explain the differential survival and reproduction of species, based upon how well they are adapted to environmental conditions. The original phrase used by Darwin is ‘descent through modification,’ a phrase that avoids misunderstandings regarding the meaning of the word ‘fit.’ One need not be overly familiar with history to realise that such misunderstanding fuelled the eugenics movement of the 20th century, an unintended and horrific social experiment most notably associated with Nazism. This example demonstrates one of the limitations of science: its vulnerability to misunderstanding. Very often, people find a meaning in science which is not scientifically warranted or socially justifiable.

On the other hand, people are also capable of seeking to diminish the findings of science. Young Earth Creationists, for instance, dismiss evolution as merely a theory. In everyday language, the word ‘theory’ is akin to a hypothesis or best guess, but in science, a theory is an explanation or model based on observation, experimentation and reasoning. A scientific theory has been tested and confirmed as a general principle that helps to explain and predict natural phenomena.

The Theory of Evolution is supported by considerable evidence from a wide variety of studies within evolutionary biology. There is broad agreement that modern humans have developed relatively recently from the evolving history of life on earth and that all life on earth today evolved from single-celled organisms, known as LUCA, the Last Universal Common Ancestor, which is estimated to have lived over 3.5 billion years ago. Human evolution is particularly complex and is the most debated issue in modern evolutionary biology.

Given that scientific theories are subject to change as new discoveries are made, it is often difficult and possibly foolhardy to closely integrate scientific findings with religious doctrine. The history of the relationship between science and faith is probably best captured by individuals who use philosophy to bridge the gap between them. For instance, the first cause argument of St. Thomas Aquinas provided a very useful framework for scientific enquiry. The first cause argument liberated the experimental methods of science from supernatural considerations, while at the same time grounding all science in the first cause, who is God. This may seem like a somewhat hands-off approach, but it could be argued that it was precisely this approach that led to the development and success of science in the Western world.

The Church promulgates teachings of faith, as given to us through sacred Scripture and tradition, but does not make official pronouncements on matters of science, which lies outside her authority. Instead, the Church responds to scientific matters that impact on theological or spiritual issues. Therefore, the Church offers no official position on any scientific theory. It is important to understand this distinction before exploring the Church’s position on matters relating to evolution. Nevertheless, we can say that in the Church’s view, science and faith are complementary to each other and mutually beneficial. It is also worth noting that the Church does not require Catholics to believe in evolution or any other scientific perspective.

As early as 1907, the Catholic Encyclopaedia stated that the Theory of Evolution ‘is in perfect agreement with the Christian conception of the universe.’ In 1950, Pope Pius XII issued the encyclical, Humani Generis, which specifically mentions the significance of evolution from a faith perspective: ‘Evolution of the body and nature does not contradict Catholic doctrine, so long as it is held that God is the first cause of the universe.’ Similarly, in a general audience on April 16, 1986, entitled ‘Humans are Spiritual and Corporeal Beings’, Pope John Paul II acknowledged that the human body could have been gradually prepared over time and that evolution was more than just a hypothesis. However, this focus on the evolution of the human body should not lead us to conclude that evolution explains everything. In other words, the theory of evolution does not explain all of reality. We simply don’t know enough about the incredibly rich biodiversity of our planet or about the origin of life itself to understand everything concerning life.

Theologians have attempted to answer the question of how the theory of evolution impacts on faith. A variety of possible solutions have been proposed. Ilia Delio and John Haught suggest that the redemptive power of Christ’s suffering is heightened in an evolving cosmos that includes sin, evil, suffering and death. There are also theologians who favour the view of original sin as simply a state of spiritual impoverishment or lack of grace. Other theologians, such as the Catholic palaeontologist Daryl P. Downing, argue that the selfishness programmed into the human genome through natural selection from its origins makes a strong case for the reality of original sin passed from generation to generation. A common feature of the work of these scientifically informed theologians is that the Biblical accounts of human origins remain relevant in the modern world. The prehistoric events described between God and the first humans remain foundational to untangling the reality of our lives.

For people interested in how science impacts our living faith, Pope Francis’ encyclical, Laudato Si (2015), could not be more useful or enriching. This scientifically informed document is a profound invitation to everyone on the planet to care for our common home.

A variety of resources exist, which guide people through important dialogues in relation to science and faith. Three relevant websites include:

1. presents the Interdisciplinary Encyclopaedia of Religion and Science, which is edited by the Advanced School for Interdisciplinary Research (ADSIR), operating at the Pontifical University of the Holy Cross, Rome.

2. A website of one of the oldest astronomical research institutes in the world,, is maintained by the Vatican Observatory and contains a library of useful articles, videos, and links to internet sites on the topic of Science and Faith.

3. is the website of the Society of Catholic Scientists, an international lay organisation which witness to the harmony of faith and reason.

It seems self-evident that we should attempt to research the Church’s answers to pressing issues, rather than assuming they do not exist, or promoting a false view of the Church. As Catholics, we have an obligation to seek and defend the truth. After all, if science and faith together have anything profound to tell us, it is that seeking truth goes to the very heart of what it means to be human.

Dr Sean O’Leary recently retired as Teaching Practice Supervisor in UCD. He has worked extensively in teacher education. His scholarly writing is found in volumes published by the International Council for Associations for Science Education (ICASE); the scientific publisher, Elsevier; the European Agency for Special Needs and Inclusive Education; UNESCO, Doctrine & Life, and elsewhere. He has written for a general readership in The Hook of Faith (