(A) The Catholic Church has repeatedly made clear that biological evolution is compatible with Christian belief. For example, Pope Benedict XVI said in a 2007 speech,
“They are presented [by some people] as alternatives that exclude each other. This clash is an absurdity … [T]here is much scientific proof in favor of evolution, which appears as a reality that we must see and which enriches our understanding ….” 1
Pope St. John Paul II, said in an important address to the Pontifical Academy of Sciences in 1996,
“[N]ew knowledge has led to the recognition of evolution as more than a hypothesis. It is indeed remarkable that this theory has been [increasingly] accepted by researchers, following a series of discoveries in various fields of knowledge. The convergence [of these results] is in itself a significant argument in favor of this theory.” 2
The truth of biological evolution has been accepted by the overwhelming majority of Catholic scientists, philosophers and theologians for many decades.
(B) The Catholic Church never at any time condemned the theory of evolution. This can be seen from the following statement in a book on Catholicism called The Question Box, published in 1929 with the approval of Church authorities and widely used in Catholic schools in that era: “As the Church has made no pronouncement upon evolution, Catholics are perfectly free to accept evolution, either as a scientific hypothesis or as a philosophical speculation.” 3 The article on “Catholics and Evolution” in the Catholic Encyclopedia, written in 1909, and also published with the approval of Church authorities, first described the basic idea of evolution and then said, “This is the gist of the theory of evolution as a scientific hypothesis. It is in perfect agreement with the Christian conception of the universe.” 4 St. John Henry Newman, widely regarded as the greatest Catholic theologian of the 19th century, wrote in 1874, “I see nothing in the theory of evolution inconsistent with an Almighty Creator and Protector.” 5
It is true that for a period of several decades after Darwin proposed his theory (in 1859) many Catholic theologians had serious concerns and doubts about aspects of evolution. These were almost entirely about the evolution of human beings, rather than about the evolution of other species or about natural selection. This was because human evolution raises highly important questions about human nature, morality, the human spiritual soul, and the doctrine of Original Sin. (See Questions 5 and 6 for more detail on this.) The position that ultimately prevailed within the Catholic Church was that the evolution of human beings at the physical level is consistent with the Catholic faith as long as the spiritual soul is understood to have been conferred by God directly (i.e. not by physical causes alone) upon the first human beings, as upon all subsequent human beings. This position was given official toleration in Pope Pius XII’s 1950 “encyclical letter” Humani generis,6 the first pronouncement ever made about evolution by the “universal magisterium” of the Catholic Church. (The word “magisterium” refers to the popes and the bishops collectively in their role as authoritative teachers of Catholic doctrine.)
It should be noted that the popes whose statements were quoted above were not intending to give official “endorsements” of evolution. The popes and bishops have made clear repeatedly in recent decades that it is not the role of the Church, nor within her competence, to pass judgment on questions that belong to the empirical sciences.7
1.. Benedict XVI, Meeting with the clergy of the Dioceses of Belluno-Feltre and Treviso in Auronzo di Cadore (July 24, 2007), http://w2.vatican.va/content/benedict-xvi/en/speeches/2007/july/documents/hf_ben-xvi_spe_20070724_clero-cadore.html.
2.. John Paul II, “Magisterium is Concerned with the Question of Evolution for It Involves the Conception of Man,” Message to the Pontifical Academy of Sciences (October 22, 1996), 4, http://inters.org/John-Paul-II-Academy-Sciences-October-1996.
3.. The Question Box, 2nd ed., Bertrand L. Conway, (New York: Paulist Press, 1929), 8-9.
4.. E. Wasmann, “Evolution,” in The Catholic Encyclopedia, Vol. V (New York: The Gilmary Society, 1909), 654.
5.. Letter to Rev. David Brown, in John Henry Newman Letters & Diaries (Oxford: Oxford University Press, 1973), 27.43.
6.. Pope Pius XII, encyclical letter Humani generis, section 36. http://www.vatican.va/content/pius-xii/en/encyclicals/documents/hf_p-xii_enc_12081950_humani-generis.html
7.. Second Vatican Council, Gaudium et spes (“Pastoral Constitution on the Church in the Modern World”), section 36. http://www.vatican.va/archive/hist_councils/ii_vatican_council/documents/vat-ii_const_19651207_gaudium-et-spes_en.html
Pope John Paul II, Address to the Pontifical Academy of Sciences, November 10, 1979, “On the Centenary of the Birth of Albert Einstein.” Section 5. http://www.va/content/john-paul-ii/es/speeches/1979/november/documents/hf_jp-ii_spe_19791110_einstein.html
Resources for further study
St. John Paul II, General Audience, April 16, 1986, “Humans are Spiritual and Corporeal Beings” http://inters.org/John-Paul-II-Catechesis-Spiritual-Corporeal
St. John Paul II, Address to the Pontifical Academy of Sciences, October 22, 1996, “Magisterium is Concerned with the Question of Evolution for It Involves the Conception of Man” https://humanorigins.si.edu/sites/default/files/MESSAGE%20TO%20THE%20PONTIFICAL%20ACADEMY%20OF%20SCIENCES%20(Pope%20John%20Paul%20II).pdf
Communion and Stewardship: Human Persons Created in the Image of God, International Theological Commission (chaired by Cardinal Ratzinger), July 23, 2004, sections. 62-69. http://www.vatican.va/roman_curia/congregations/cfaith/cti_documents/rc_con_cfaith_doc_20040723_communion-stewardship_en.html
Religious Faith Meets Modern Science, Paulinus F. Forsthoefel, S.J. (Alba House, 1994).
Faith, Science, and Reason: Theology on the Cutting Edge (2nd edition), Christopher T. Baglow (Midwest Theological Forum, 2019) Chapters 8, 9.
Video: “Evolution and the Catholic Faith” (lecture by Stephen M. Barr, sponsored by the Lumen Christi Institute) https://www.youtube.com/watch?v=otSp_8otQ1s&t=2077s