Some years ago a Jesuit, and yet a friend, warned me of “Thomistic howlers.” That is to say, sometimes, though rarely, St. Thomas Aquinas — I like to refer to him as the Church’s Common Doctor — made bad mistakes.

Right. And who of us has not? Did not Aristotle famously say that Plato was a great friend but that truth was a greater friend still?

Recently a former student (now a professor of law at Fordham) reminded me of a Thomistic howler. Well, maybe it is.

Consider the case of a judge who knows privately that a man about to be found guilty is in fact innocent. Thomas advises us that the judge must examine the witnesses with great care to find grounds for acquittal and, failing that, try to recuse himself. But suppose both measures fail to secure justice?

Then, Thomas continues, the judge “does not sin if he pronounce sentence in accordance with the evidence, for it is not he that puts the innocent man to death, but they who stated him to be guilty” (ST II-II, q. 64, a. 6, ad 3).

Thomas wants to honor the integrity of the judicial system in upholding the common good. Nonetheless, the judicial system itself fails to uphold the common good when it sanctions the killing of the innocent. With a tip of the hat to Rose Mary Lemmons for the citation, St. John Paul II teaches that “The fundamental moral rules of social life…entail specific demands to which both public authorities and citizens are required to pay heed. Even though intentions may sometimes be good, and circumstances frequently difficult, civil authorities and particular individuals never have the authority to violate the fundamental and inviolable rights of the human person” (Veritatis Splendor, no. 97).

The mission of the judicial system is to uphold the common good. But the judicial condemnation of the innocent is an attack on the common good, indeed an attack on those who do their part to uphold it. So one does not undermine the integrity of the judicial system when one acts, whether as a judge or as a private person, to prevent that system from undermining its own purpose.

Should we, then, judge the Common Doctor to have served up a “howler” in his account of the judge whose predicament we have been exploring? For my part, I think not and for three reasons.

First, John Paul II argues as he does on the basis of core principles of Thomistic natural-law thinking. Second, were Thomas to read John Paul II’s Veritatis Splendor he would find himself in wholehearted agreement. Third, Thomas’s collected works range to some eight million words. That we should find in this imposing oeuvre the occasional internal tension is predictable. But such a tension falls far short of being a “howler.”

Still, there is a lesson — indeed, more than one — from this brief foray into a difficult passage from the Common Doctor. A signal lesson is that the common good includes the good of each person, and we ought never to confuse the common good with a utilitarian summing up of individual interests. A second is that the common good is sharply different from a social contract. Indeed, it is the primacy of the common good, with its unshakeable commitment to the inviolable right to life of the person, that is the foundation of our demanding justice of every social contract and of every political regime.