Natural Law, Aquinas, and the persecution of heretics


I decided to do Moral Theology for this thread since it has to do with natural law, but I’m Evangelical so it could conceivably go in NCR as well. I’m not entirely sure if this is the right choice, it’s my first time going outside the NCR sub forum so we will see if this stays here.

Thomas Aquinas is the main man when it comes to the foundation of natural law. I think this is pretty well known, so I’m just stating it without a source, although primary sources would surely include potions of Summa Theologica. I’ll include some sources that define natural law, however, for anyone who’s interested in participating but isn’t familiar with all the particulars.

Besides natural law, Aquinas handles a whole lot of different topics in Summa. One of those topics is the persecution of heretics. In the second part of the second part, question 11, all sorts of issues pertaining to heresy are addressed.

If you scroll down there to Article 3, Aquinas repeatedly and explicitly argues that heresy and heretics should not be tolerated. Solely because of corrupting the faith and publicly teaching against the Church, heretics deserve punishment, the most obvious of which he immediately states is capital punishment.

“…they deserve not only to be separated from the Church by excommunication, but also to be severed from the world by death.”
“…much more reason is there for heretics, as soon as they are convicted of heresy, to be not only excommunicated but even put to death.”

This is disappointing to me for a number of reasons, not least of which are personal, on account of a deep admiration for some heretics centuries after Aquinas who would become known as Protestant Reformers, alongside an otherwise deep admiration for Aquinas and that awkward feeling you get when you really like someone and then they do something that you find repugnant and/or evil.

Of particular note, however, is this reason. This seems to be inconsistent with the much-better-known work of Aquinas on the topic of natural law. It seems pretty evident that there is an argument to be made for religious freedom on account of natural law, meaning that (in essence) religious freedom is universal, and people who make the switch to Catholicism have the same rights as those who make some sort of switch away from it.

And yet here is Aquinas saying that heretics, once convicted, deserve death.

Of course, I am not saying that Aquinas formally speaks on behalf of the Church. Nor am I saying that Aquinas has blood on his hands, or that he has produced doctrine in these things that I’ve brought up. Let’s not make it about anything that it’s not about.

So let’s clarify.

Aquinas is chiefly responsible for the development of natural law theory. This is not doctrine or dogma, but it sure is an important piece of Catholic moral theology. Oh boy is it important. Yes I am clear on the concept that this is not doctrine, and yes I do think that last part about its importance to Catholic moral theology constitutes a very good reason to talk about it despite the fact that it’s not doctrinal material.

Now, to the best of my current understanding, any argument from natural law concerning religious freedom seems to most naturally support a universal code of religious freedoms for all humanity, and my reason for thinking this comes from any basic definition of natural law. However, it would seem that the spiritual father of natural law theory does not reach any sort of conclusion remotely similar to this.

Let’s make this our starting point. From a Catholic perspective- and it helps if you’re well versed in Aquinas, of course- how does one go about locking the horns of natural law theory with this heretics-deserve-death business? It seems like a violation of natural law, but apparently Aquinas did not see it as a glaring inconsistency.

From a logical standpoint, how does this make sense within the Thomistic construct of natural law? And if anyone has intimate knowledge of the situation- is it possible that the concept of natural law has significantly changed since the lifetime of Aquinas in ways that allow this thing to make more sense? If so, in what ways has it changed, particularly in specifically Catholic arenas?


I believe from Aquinas’s perspective, justice-the right order of things-demands faith from human beings, whereas lack of faith leads to chaos, disorder, injustice. This would be consistent with natural law and the need to rid society of heretics. Today the Church teaches essentially the same thing; while man must be free to decide for himself, justice nonetheless obliges him to believe in, hope in, and love God. This choice actually first arose in Eden.


Or, more specifically, to Aquinas, it is a form of self defense.

Who is the one who does greater harm, the one who kills the body, or the one who kills the soul?

The killer of the body ( a murder) is deserving of a death sentence, both as Justice, and to protect others from physical harm. It follows, therefore, , the one who murderers the soul should, at least be as deserving of death, if only to protect others from spiritual harm.


I am sorry you feel that way about Protestant Revolutionaries and other heretics. But practically all of them survive their persecution, so I don’t see much of a problem. Part of Catholic doctrine is that we all deserve death for any one of our mortal sins, but that God is merciful enough to forgive us easily and often.

I find myself taking issue with your statement “Solely because of corrupting the faith and publicly teaching against the Church, heretics deserve punishment, the most obvious of which he immediately states is capital punishment.” Personally, I can’t imagine a worse crime. As Brendan said, murderers are lower on the scale of things here than teachers of heresy. And I think we’re both clear that this is not simply a material heretic who denies some doctrine, it’s someone who publicly espouses contrary doctrine, and usually multiple doctrines, and actually engages in sheep-stealing, leading people away, en masse, from the True Faith.

The Protestant Revolution did lasting damage to the Body of Christ. If I may suggest a great book to you: , by Steve WeidenkopfThe Real Story of the Reformation. The Revolutionaries did not succeed in their goal of destroying the Church, but they dealt a critical blow to unity, and in so doing, set in motion all the following momentous events in modern Western history. I don’t doubt that the Sexual Revolution is one of the rotten fruits of the same Protestant Revolution, 500 years on.

Let’s be frank. It may not have been possible to stop the Revolution, once the wheels were set in motion, even if every single leader were hunted down, prosecuted and executed. We saw how effective it was to execute the first Christian leader and thousands of His followers… but I think that operating as a deterrent, if heretics are afraid to speak out because their words might condemn them, and combined with other methods, it could be partly effective.

Take this all with a huge grain of salt, though. The Catholic Church is moving beyond capital punishment in a very real way. She will never go back to the days of Aquinas and the Inquisition. Today we have the words of St. John Paul the Great, who in his encyclical Evangelium vitae, quoted the Catechism to say “If bloodless means are sufficient to defend human lives against an aggressor and to protect public order and the safety of persons, public authority must limit itself to such means, because they better correspond to the concrete conditions of the common good and are more in conformity to the dignity of the human person.” (#56) The USCCB has called for the abolition of the death penalty. Three notable US Catholic news publications called for it as well. Francis doesn’t like it either. There is critical mass in the Church and in society in general to abolish the death penalty altogether. So I seriously doubt it will be used on many people in the future, at least in Western societies, and certainly not any Catholic heretics.


Actually, Aquinas held the opposite, that the death of the soul was more grave than the death of the body, those that kill the soul do the greater wrong.

And I think we’re both clear that this is not simply a material heretic who denies some doctrine, it’s someone who publicly espouses contrary doctrine, and usually multiple doctrines, and actually engages in sheep-stealing, leading people away, en masse, from the True Faith…

That would be correct, Aquinas’ comments were in regards to those who were active formal heretics.


Executing heretics was just plain wrong-headed and in opposition to the gospel. This holds true regardless of our understanding of the act in light of the times involved-which were very different from our own in many ways. And this is the very reason why the Church has been moving to an increasingly pro-life stance in every instance.


Not necessarily, look at the Gospel from Mass today

Whoever causes one of these little ones who believe in me to sin,
it would be better for him if a great millstone were put around his neck and he were thrown into the sea


No, that’s what I meant, where higher on the scale would be the graver offenses.


And yet I doubt Jesus would’ve ever instructed anyone to tie on the millstone and throw its partner into the sea,


Jesus supports the death penalty.


OK. I guess the recent popes are wrong then.


Non-Catholics must come to the Faith of their own free will. Catholics have had the Faith given to them, so they, at least, must not disturb those in the Faith by preaching heresy to them.

Two different sets of people.


We are talking about the guy who nuked Sodom and Gomorrah, so I would not be too sure.


Luke 9:
53 But the people did not receive him, because his face was set toward Jerusalem.

54 And when his disciples James and John saw it, they said, "Lord, do you want us to tell fire to come down from heaven and consume them? " { Some manuscripts add b as Elijah did b }

55 But he turned and rebuked them. { Some manuscripts add b and he said, “You do not know what manner of spirit you are of; for the Son of Man came not to destroy people’s lives but to save them” b }

56 And they went on to another village.

It’s amazing that some people still think like the Disciples did here.


We are talking about the guy who loved and forgave his persecutors, his enemies, all the way to death, the guy who didn’t condemn, and instructed us to do the same. Jesus offered light unto the world, not the same old same old.


It seems to me that we must deal with several items in the Summa II-II:

#1. Question 11 Article 3 seems to say that heretics should not be tolerated: “they deserve not only to be separated from the Church by excommunication, but also to be severed from the world by death.” And: “much more reason is there for heretics, as soon as they are convicted of heresy, to be not only excommunicated but even put to death.” And: “the Church…delivers [them] to the secular tribunal to be exterminated thereby from the world by death.”

#2. Question 10 Article 11 seems to say that heretics may sometimes be tolerated: “the Church, at times, has tolerated the rites even of heretics and pagans, when unbelievers were very numerous.” And: “[Their] rites…[may] be tolerated…in order to avoid an evil, e.g. the scandal or disturbance that might ensue, or some hindrance to the salvation of those who if they were unmolested might gradually be converted to the faith.”

#3. Question 10 Article 8 seems to say that pagans and Jews should ordinarily be tolerated: “[T]he heathens and the Jews…are by no means to be compelled to the faith, in order that they may believe, because to believe depends on the [free] will.” And: “Christ’s faithful…wage war with unbelievers, not indeed for the purpose of forcing them to believe, because even if they were to conquer them, and take them prisoners, they should still leave them free to believe, if they will.”

I think there are statements in each of those sections that seem, at first sight, to be in tension with one another. E.g. heretics should not be tolerated, but the Church tolerates them when they are very numerous “for example.” <-- That seems contradictory, at first glance, at least to me. Also, one of the reasons he gives for tolerating pagans and Jews is that “to believe depends on the [free] will.” This seems at first glance to apply to heretics also, and it also appears to be the kind of “natural law argument” you seem to be looking for.

By reconciling the tensions that I think are there on the surface, and perhaps with other considerations, I think St. Thomas could be defended and it could be shown that he did not think heretics should ordinarily be killed, but only in exceptional circumstances, perhaps some that would be agreed to by the modern Church. (Or maybe St. Thomas simply got this wrong, which I suppose is also possible.)

A partial help re: #1, but not a complete help, comes from a distinction St. Thomas makes between what heretics deserve and what the Church actually does to them: “With regard to heretics two points must be observed… On their own side there is the sin, whereby they deserve…death…as soon as they are convicted of heresy… On the part of the Church, however, there is mercy which looks to the conversion of the wanderer, wherefore she condemns not at once, but after the first and second admonition.”

A summary of that would seem to be that, even though St. Thomas thinks there is a sense in which heretics deserve immediate death, yet the Church does not give them that, but gives them two chances to repent.

Still, that seems to make the Church complicit, in St. Thomas’ view, in killing at least heretics who don’t repent. But not all unrepentant heretics. He is only talking about some here, since he says explicitly in other places that the Church sometimes tolerates heretics, and gives several reasons why. (See #2 above.)

Another thing that I think helps us understand #1 is in Question 11 Article 3 Response 3. Now, this is in the section that defends the perspective that heretics should Not be tolerated. In answer to an objection, he refers to Question 10 Article 8 Response 1 for further explanation on why executing heretics is not contrary to the parable of the wheat and the weeds. But when you look at that section, it is only talking about Some cases: “when a man’s crime is so publicly known, and so hateful to all, that he has no defenders, or none such as might cause a schism, the severity of discipline should not slacken.”

In my opinion, that is a very limiting factor, and helps me reconcile some of the tension I see between #1 and #2. If St. Thomas in Question 11 Article 3 is discussing the execution of the same kinds of heretics discussed in Question 10 Article 8, and there is evidence for that, then it seems that he is not referring to all heretics, because Question 10 Article 8 is not referring to all heretics (at least I don’t think it is), but only to ones who have no defenders, whose crime is hateful to all, and (perhaps) who are feared to cause a schism.

If that interpretation is correct, that is more defensible to me from the modern Church’s perspective. The modern Church does not forbid using the death penalty in all possible cases, but only says that in modern times there is no need and therefore we should not. But if a heretic in times past committed certain crimes (e.g. violence, perhaps rebellion against a lawful government), and if (in the past) execution was the only way of stopping them, the Church’s principle regarding the just application of the death penalty would, I think, permit them to be executed. And a schism in that time involved more crimes than just heresy – whole sections of the Church split off, taking property with them that did not belong to them, including churches, cathedrals, and monasteries. I think it is right for the Church to use the secular arm to prevent such things from occurring, and if the instigators were executed after two or three warnings, I can sympathize with that, even though I think it is better to simply put them in jail.

I hope that helps. Please ask me for clarifications or show me where I’ve gone wrong, because I don’t think either myself or St. Thomas are infallible.


BTW St. Thomas lived long after many of the founders of the principle of natural law, and is, at least in my mind, definitely not the “main man” when it comes to natural law’s foundation. He’s just too late to the game.

Just as one example, St. John Chrysostom discussed natural law at length in several of his homilies, including this one: “[W]hen God formed man, he implanted within him from the beginning a natural law. And what then was this natural law? He gave utterance to conscience within us; and made the knowledge of good things, and of those which are the contrary, to be self-taught. For we have no need to learn that fornication is an evil thing, and that chastity is a good thing, but we know this from the first.” It continues in the source.

Many prior Church Fathers and Doctors discussed natural law. St. Irenaeus mentioned it as early as 180 A.D. - “At first God deemed it sufficient to inscribe the natural law, or the Decalogue, upon the hearts of men; but afterwards He found it necessary to [institute]…the Mosaic law.” source

Search “natural law” in the Church Fathers Search Engine for more examples.


They’re not “wrong” they are simply exercising the prudential judgement factor in opposition to maintaining the status quo of widespread capital punishment in today’s civilized societies. Jesus never said we couldn’t change our criteria of application so that it was almost nonexistent.*

*And by “Jesus said” I am of course referring to the fullness of the Word of God, not merely in the Gospel sayings of Christ on Earth, but also the Living Word given in all of Scripture and Tradition.

But please stay on topic. I would not want for this to become a thread solely on the modern application of Capital Punishment because we have had too many of those for too long. The OP had an insightful and engaging question, and we should concentrate on discussion of it and not the merits of CP.


Well, the prolife position of the Church as it relates to CP & and as both relate to the burning of heretics is very much in tune with the OP I would think.


I am curious as to what you consider the natural law case for religious freedom. I can give a Thomistic precis of how religious liberty might play out, but I don’t think it will be the same thing you seem to be gesturing at.

The core precept of the natural law is that we must do/pursue good and avoid evil. A reformulation or very near corollary of this would get us to the principle that we are obliged to conform our intellects to the goodness of truth. Thus every human being has a duty to believe the truth, insofar as it is knowable to him. Since the truth is an objective reality unaltered by our concurrence or rejection, this sets up an asymmetrical relation - we must always be free to advance toward, embrace, and abide in the truth. We are never morally free to do the opposite (toward error), even if we might be free from coercion.

That freedom from coercion results from the limited competence of the State. The job of the State is to secure the common good, the earthly conditions in which all members of society will be able to reach their ultimate end in the enjoyment of God (yes, the *natural *common good goes beyond temporal security to include matters such as virtue and intellectual formation!). But in accomplishing that task it uses authority wielded by human beings to work upon human beings, which means that the State cannot judge the state of people’s souls or beliefs and, even if it could, is acting upon free creatures whose interior disposition lie beyond the reach of coercion - one can either only enforce outward conformity, in which case the true interior faith/disbelief remains intact, or else if an interior decision really does arise from coercion it was not free and thus not a true human act (of faith, etc.) The State, then, in summary, is limited to mandating *outward *behavior directed toward public/common, and never private, good.

A further qualification is that while “The end (i.e., aim) of the law is to make men virtuous,” trying to impose a burden greater than an initially vicious population can bear will simply produce disobedience, and thus contempt for the law, and an overall decrease in the level of public order and virtue. So while every individual virtuous (public and exterior) act may be commanded by the law, it is not the case that all of them at once should or even can be imposed. Here we get toleration of evils. They should theoretically be illegal. Over time as we succeed in training our people in virtue we might be able to criminalize them. But for now it is best overall to let them go unpunished.

How does this cash out with religious faith? The law can never command that people believe certain truths. But it is supposed to support their realization of the truth. So it should not be the case that a person who “switches” to Catholicism is treated just the same as one who “switches” away. Because while Catholicism, being revealed, may have moved onto the supernatural plane, the natural law reasoning still tells us that part of the State’s job is to direct people toward attainment of the truth, and we just happen to know of more truth than would have been naturally attainable. I’ll follow up with an explanation of state-enforced penalties for deviation from truth.

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