Every other Monday, New Wine New Wineskins posts abbreviated versions of papers given at the annual NWNW conference in July. This week, enjoy Patrick Haley‘s reflections on St. Thomas and the problem of religious “bad apples.” And check back each Monday for more content from NWNW!

Communities rarely take responsibility for their wayward members in the way they ought. For example, when police officers are found guilty of misconduct, others are quick to assert that these “bad apples” have no bearing on police institutions or practices. Christians have fallen prey to similar temptations. Confronted with groups such as Westboro Baptist Church, the Slaves of the Immaculate Heart of Mary, or historic perpetrators like the crusaders, Christians are tempted to say, “Sure, but those aren’t real Christians.” Journalist Chrissy Stroop has both documented this rhetorical ploy and begun explaining why it is a mistake.

Yet there are times when we need to denounce unjust and/or confused members of our communities, not only so that they might amend their ways, but also so that everyone else knows that the Christian community writ large does not stand for such actions or beliefs. It turns out that St. Thomas Aquinas has a framework for judging when such condemnations are just and due. However, that discussion leads us back to several terms that have rightly fallen into disuse: heresy, apostasy, and heathenism.

What is surprising, given these terms’ fraught histories, is that Thomas thinks our default stance toward anyone who has never belonged to our faith community (he calls them heathens) ought to be toleration. By and large, we ought to take responsibility for our own communities and leave it to others to judge their own, for as St. Paul says, “What have I to do with judging those outside? Are you not judges of those who are inside? God will judge those outside” (1 Cor. 5:12-13).

By contrast, Thomas thinks we must take responsibility for fellow Christians and those who once belonged to the faith. Heretics are those who think they still represent Christ’s teachings, but are actually in error. The danger—as we well know when anything posted on the Internet is accepted by someone as true—is that human beings are disposed to trust others or, at least, grant what others say for the sake of conversation. Philosopher Philip Pettit has shown how this dynamic plays out in everyday conversations and therefore why it is so important to call out errors when we see them.

Meanwhile, although apostates no longer claim to belong to the community, they may nevertheless represent that community based on prior acquaintance. So, for instance, one prominent evangelical pastor’s son became famous on TikTok for describing evangelical religion and culture. When people belonging to the community believe those descriptions are misleading, they ought to speak up.

For his part, Thomas thinks that we must not only denounce heretics and apostates as false representatives, but also excommunicate them to clarify where they stand in relation to the community. For many of us who want to live peaceably with all, these repercussions may sound worrisomely inquisitorial. But Thomas helps us to see both when these consequences are necessary and how to circumscribe their application to a rather narrow sphere of responsibility.

This wisdom could not be more relevant. We live at a time when people have rediscovered the need to hold unjust persons and institutions accountable—and very often they are right to do so! Yet as we take up practices such as boycotting to deplatforming, we need to think carefully about why we do so and who deserves such treatment. Thomas thinks, to use St. Peter’s words, that “the time has come for judgment to begin with the household of God” (1 Pet. 4:17). Christians ought to take responsibility for other Christians—even and especially the bad ones—and not evade such responsibility. And we hope and pray that other communities will do the same. Perhaps in doing so they will even look to Thomas for guidance.

Patrick Haley is a PhD candidate in Christian Ethics at Princeton Theological Seminary, where he works on disambiguating the language Christians use to regulate their practices and express their beliefs.