Updated: May 29, 2021
By Luke Lancaster
Vatican II and Pope John Paul II have said that slavery is wrong in Guadium et Spes and Veritatis Splendor. Did that indicate that the Church had changed Her teaching on holding slaves? Judge John T. Noonan argues that She has. He points to the many Catholics, even saints and religious orders, who have held slaves without realizing its hideousness. Now, Noonan is correct about the saints and religious orders, but is incorrect about the Church changing Her teachings. The Church had never officially declared that slavery was acceptable, and then officially declare that slavery was unacceptable. Rather, a development has occurred. There was a lack of clarity and unity in the Church on the issue of slavery, as has occurred with nearly every teaching. For there can be disagreement on an issue before it is officially defined. See this post for more info. Some have seen slavery as acceptable, others have seen slavery as detestable, but the debate ends once the Church officially settles the matter.
Disagreement: Slavery is acceptable
Noonan points out how many saints and religious orders have cooperated with the evil of determining the “identity, education, and vocation of the slave and to possess the fruit of the slave’s body” (See The Church That Can and Cannot Change by Noonan). He states that Pope Gregory the Great learned about young boys from Britain being sold in a slave market in Rome, yet did not do anything about it. Instead, he sought the conversion of Britain, and bought some boys himself! Pope Gregory is not alone, for Popes have “supported slavery in various other ways” throughout history (Noonan). Many non-Christians will also point to texts in Scripture which seem to accept the practice of slavery, such as Colossians 3:22 or Ephesians 6:5.
Now, throughout Church history, it has been thought that you could own a slave, provided your treatment of him was like a brother. For owning a slave was considered a "constituent element of fallen society" (Engaging the Doctrine of Revelation, by Dr. Matthew Levering). It was a "permissible" evil, as Aquinas put it.
Disagreement: Slavery is unacceptable
Scripture also speaks about slavery in negative terms. For example, the Israelites were not allowed by God to enslave fellow Israelites (Exodus 21, Nehemiah 5). Paul’s letter to Philemon does not allow it, either. For in it, Paul (who is in prison) has gotten to know Onesimus (a run-away slave) and pleads with the owner of Onesimus (Philemon) to take him back. The way Philemon was to take him back was in a way that was unheard of in the 1st century Roman empire. Philemon should let Onesimus be free,
“no longer as a slave but more than a slave, as a beloved brother, especially to me but how much more to you, both in the flesh and in the Lord. So if you consider me your partner, receive him as you would receive me” (Philemon 16-17).
A slave was to be treated "no longer as a slave" but as a "beloved brother" in the Lord. There was no distinction between slave and free, for all had become one in Christ (Gal. 3:28). This teaching is spoken about by various Christians throughout history. St. John Henry Newman said in his great Essay on the Development of Doctrine that St. Gregory of Nyssa (335-395) gave a homily against slavery with great passion. St. Anselm (1033-1109), “presided over a Church council in London that banned the slave trade" (Newman). Theologians spoke out against slavery and the slave trade when it moved to the Americas, such as Cardinal Cajetan (1469-1534). Many popes condemned the African slave trade, even before it gained traction. Pope Eugene IV argued to end the slavery of the inhabitants of the Canary Islands off of the coast of Africa in his Papal bull, Sicut Dudum (1435 AD). Note that this was before Columbus discovered America in 1492.
There was disagreement in the Church about slavery, and this moral teaching was not formally condemned until John Paul II addressed it. Just as every doctrine in Church history has gone through, there was disagreement until the Church officially said something. The teachings of Original Sin and the eternal nature of Hell were denied by Origen of Alexandria in the 200's and were not official teachings of the Church within the Nicene Creed. It took some time for these teachings to develop. Heck, the doctrine of the Trinity took centuries to be explicated. Many pre-Nicene (before 325 AD) Christian leaders were silent or contradicted the more fully developed teaching proclaimed at Nicaea.
The fact is, what Vatican II and John Paul II taught was not an invention. There was a tradition behind it, for “Scripture and the theological tradition viewed slavery in negative terms (even when accepting it)” (Levering). There would only be a change in teaching if the Church had officially declared slavery to be acceptable one day, but contradicted that officially declared statement the next. A big problem with Noonan is also that he equated the actions of the Church in accepting slavery as if it were definitive teaching. The personal practice of Pope Gregory is not definitive teaching!