In reply to a follow-up here, another posting on Sacramentum Vitae raises a rather large number of issues, but I will confine myself to replying only to what seem to me to be the substantial ones. Michael says:

Now I had also asserted that Aquinas justified the "torture" as well as the execution of heretics. Paul naturally asked me to document that assertion; and of course I can't, because Aquinas never said anything about it. Yet the torture of heretics was not exactly uncommon in his day and was quite well known to Aquinas. And so my statement is really the conclusion of an argument from silence, whereby I take Aquinas' silence as consent. Admittedly, that kind of argument is pretty weak.

I asked for a reference for that assertion because I had never seen Aquinas write anything on torture, nor had I seen a quote from him mentioned in any of the numerous postings around the blogs when torture was being discussed. The issue that my question flagged is not one that requires making any kind of estimate — weak or otherwise — of what it was that Aquinas might have thought about torture. It was that your posting would give the ordinary reader the impression that Aquinas had indeed written something on this topic, and that this writing had stated that "obstinate, public heretics should be tortured". But in fact, as you say, he wrote nothing about torture, and the ordinary reader would come to the wrong conclusion about Aquinas if they accepted the statement at face value.

Also in relation to Aquinas:

it must be admitted that the Church's teaching about capital punishment has developed in the direction of much greater strictness about it. As Cardinal Dulles makes clear, that development occurred only in the latter half of the 20th century. Aquinas, for instance, wrote that …if a man be dangerous and infectious to the community, on account of some sin, it is praiseworthy and advantageous that he be killed in order to safeguard the common good, since "a little leaven corrupteth the whole lump" (ST IIa-IIae, q. 64, a. 2).

Though, one can look at that and see only that Aquinas wrote in one set of circumstances, and current Church teaching has taken into account that fact that the techniques available to society have altered: specifically (as Evangelium Vitae says) "as a result of steady improvements in the organization of the penal system". Because of his particular social circumstances Aquinas saw the necessity of keeping safe from dangerous and infectious people (i.e. those threatening the lives of society) as being satisfied only by their execution. But we have access to different methods. Aquinas simply does not take our possibilities into account — it would be science-fiction for him. But the fact that cutting off from society can be necessary, and the given reasons for that cutting off from society, have not changed. And in that way there is no contradiction between Aquinas and current teaching. (Take away such a penal system and techniques as we have, and what Aquinas says could become operational again.)

[Aquinas] position invokes a certain notion of social harm, such that prevention of such harm sometimes suffices to justify the death penalty. One must admit that if, as I concede, the Church's developed teaching today is binding, he went too far with that definition. Without it, he would not have justified the execution of heretics, in an era when heresy was a civil crime, as well as certain other kinds of criminals; yet as Dignitatis Humanae makes clear enough, the Church today clearly rules out the death penalty for heretics even in a Catholic state.

But Dignitatis Humanae does not absolutely rule out the death penalty for heretics. Religious rights are not absolute, but — as Dignitatis Humanae makes clear — still contingent on "just public order". If that were breached, penalties could be applied up and including the death penalty, provided that the heretics had performed actions genuinely deserving of death, with no possibility of protecting society otherwise. That may be extremely unlikely in modern circumstances, as the Pope makes clear. But circumstances can change.

I had criticized something written by Robert T. Miller in First Things, on the grounds that Miller makes an unqualified claim that empirical claims made by the Church about the state of the world can never require more than respect from Catholics. Michael thinks it obvious that:

The context of Miller's remarks make clear that he is speaking of empirical judgments in the political arena that can be reasonably disputed.

And having read Miller's remarks numerous more times, I cannot agree with Michael. If Miller is limiting his claims only to such judgments as can be "reasonably" disputed, that immediately raises the question as to what criteria Miller is using to decide whether a particular claim is reasonable or non-reasonable. But Miller never answers that question. He does indicate that intrinsic evils can't be reasonably disputed (because they plainly don't depend on empirical circumstances at all). But beyond that he gives no criteria for deciding on reasonableness.

Look at these sentences in the Catechism (#2267), that Miller quotes:

Assuming that the guilty party’s identity and responsibility have been fully determined, the traditional teaching of the Church does not exclude recourse to the death penalty, if this is the only possible way of effectively defending human lives against the unjust aggressor.

If, however, non-lethal means are sufficient to defend and protect people’s safety from the aggressor, authority will limit itself to such means, as these are more in keeping with the concrete conditions of the common good and more in conformity to the dignity of the human person.

Today, in fact, as a consequence of the possibilities which the state has for effectively preventing crime, by rendering one who has committed an offense incapable of doing harm—without definitely taking away from him the possibility of redeeming himself—the cases in which the execution of the offender is an absolute necessity “are very rare, if not practically nonexistent.”

And what Miller says about them is this:

The first two sentences concern morals, but the third sentence is an empirical claim about the state of the world and so is not about morals. The first two sentences are thus, at the very least, doctrina catholica, which Catholics must accept with a religious submission of will and intellect. The third sentence, however, is not; it need only be respected and considered in forming one’s conscience.

It is plain that Miller's stated criteria is to look at a sentence in the Catechism, and if it is an empirical claim about the state of the world, then he would see that its only claim on the conscience of Catholics is that they "respect" and "consider" it. He simply gives no other criteria. However, the criteria Miller gives can't possibly apply to all empirical claims since (as I said in a previous post) that would remove the Church's canonical authority to make empirical claims about things like (e.g.) the validity of sacraments, and have that decision received by the faithful with religious assent (which is more than just respect). So what Miller writes is logically wrong. It could be the case that Miller himself says something like, in effect: "But I also intended that …". But there is, as far as I know, nothing like that.

As written, Miller's article can't be correct — you can't just look at a sentence in the Catechism and decide that if it is only an empirical claim about the state of the world then it need only be deserving of respect. That's false. Now Michael seems to propose that Miller must obviously have some other criteria in mind that limits what he says only to "reasonably disputable" claims. But I see nothing in Miller to indicate that he thinks this, and Michael also does not say what this extra criteria might be (though he seems to implicitly admit that it must exist).

Michael goes on to say:

almost the entire dispute among Catholics these days about particular instances of capital punishment hinge on whether that sentence [ed. the third sentence from the Catechism, as quoted above] is (a) true; (b) whether or not true, binding on Catholics in the sense of requiring "religious submission"; and (c) if binding, whether its application to specific cases by Church officials is also binding in that sense. Now I believe (a) and (b) and have made that clear before. So the only point of contention is when an affirmative answer to (c) is warranted.

We are in agreement on (a) and (b). As for (c), it's too open-ended a question, and I think an answer can only be given when the specific circumstances are given.

Addressing me, Michael also says:

… [Paul] seems to take for granted that the only sort of social harm that could conceivably suffice, in certain circumstances, to justify capital punishment is lethal, physical aggression by the convict himself.

But I had said nothing that limited the harm to just that. What kinds of harm to society by the aggressor did the Pope have in mind? Evidently, whatever kinds that would be prevented by placing the convict in prison — else the Pope's prudential judgment quoted above would not make any sense. (For example, if the convict's words were somehow a threat to the lives of society, keeping him incommunicado in prison would prevent this. If necessary because of circumstances, he could also be shipped to a far-distant location, or an unknown one. Modern techniques allow all kinds of possibilities, if the will is there.)

Whatever "harm" might mean, it cannot be legitimately be a definition that would be incompatible with the Pope's prudential decision.

As for what Michael quotes Cardinal Dulles saying here, it in fact goes a long way towards supporting what I have been saying. Here is the relevant paragraph from Dulles:

Capital punishment is obviously an effective way of preventing the wrongdoer from committing future crimes and protecting society from him. Whether execution is necessary is another question. One could no doubt imagine an extreme case in which the very fact that a criminal is alive constituted a threat that he might be released or escape and do further harm. But, as John Paul II remarks in Evangelium vitae (EV 56), modem improvements in the penal system have made it extremely rare for execution to be the only effective means of defending society against the criminal.

Evidently Dulles has a very similar understanding of "harm" to mine — harm that would occur if the aggressor was not confined to prison. There is no support for a wider understanding of "harm" than that.