“Medieval tolerance” sounds like an oxymoron. Everyone knows the medievals were intolerant. Everyone knows that tolerance was invented in the modern world.
Everyone who knows such things is wrong.
Istvan Bejczy demonstrates in a 1997 essay that medieval thinkers had a well-developed concept of tolerance. He goes further than saying that medievals had a concept of tolerance. He argues that “Medieval tolerantia is a full-fledged example of what tolerance could be. It is an even more coherent and forceful concept than the rather loose notion of tolerance in modem political discourse, precisely because it has nothing to do with religious freedom or the plurality of truth.”
He deftly traces the development of the concept of tolerantia from the ancient world. First, “in Antiquity, especially in stoic writings, tolerantia stood for the bearing of anything which was a burden to the human body or, more often, to the human mind.” Early Christians gave the word a religious connotation: “It referred to the virtuous capacity of Christian individuals to endure with calm the many sufferings of earthly existence.”
The concept took on social and political connotations only in the middle ages: “In medieval scholarly writing tolerantia came to denote – analogously to some incidental examples in the works of Augustine – the forbearance of bad people (the immoral, the heterodox, the infidel) by those who had the power to dispose of them.” And from there, the word took on a specifically political sense, referring to “the self-restraint of political power, the abstinence from correctional or destructive force by the authorities governing society.”
Canon law made use of the concept in its elaborations of papal authority: “With regard to non- Christians, Gratian had left the judgment of those who are outside of the faith to God (referring to 1 Cor. 5: 12-13). Later canonists gradually abandoned this reluctance, stating eventually that the pope could uphold natural law against anybody in the world, regardless of the faith of the person in question. At the same time the notion of tolerance was applied to all nations and religions alike. Pope Innocent IV himself acknowledged, in one breath with his confirmation of universal papal jurisdiction, that the pope sometimes refrained from punishing infractions of natural law not only by lack of actual power but also because punishment seemed undesirable in certain cases.”
For medieval canonists and philosophers, tolerance of a thing did not at all soften the conclusion that the thing is evil. On the contrary, tolerantia can be applied only to evil things. If something is indifferent, tolerance doesn’t come into play. In short, “Tolerance does not imply that the evil character of the tolerated act is denied or extenuated; it means simply that certain evil acts remain unpunished.”
Judaism was often an object of tolerantia. Aquinas “alleged that the Jews sin in their rites and he called them ‘our enemies.’ His argument shows that one did not have to like the Jews to be tolerant; to the contrary, one had to dislike them to be tolerant, for tolerance only applied to evil.” In a short treatise on the government of the Jews, “Thomas did not say that the ruler must embrace the Jews as if they were good subjects; in his vision, they remain sinful outsiders but precisely because they are outsiders, Christian rulers have to bear themselves honestly to them.” Tolerance is a form of benevolence that leaves open the possibility of evangelization and conversion.
Heretics were not, by contrast, considered tolerable. Even Erasmus, often thought to be an early modern apostle of tolerance, considered heretics too dangerous to tolerate: “opinions that could not be reconciled with the Christian faith as he conceived it (more amenable though he may have been compared with some contemporaries) had to be suppressed if necessary even by the death penalty. Of course one had to try to cure heretics before inflicting capital punishment on them, but if no other remedies were effective, one had to cut off the heretical limbs from the social body in order to prevent the contamination of the whole community.” The exception was when a large section of a population is infected with heresy. It would not be good to launch a “religious war” to eradicate heresy.
Here Erasmus is reasoning with medieval tools – tolerated opinions are genuinely evil; some opinions are not to be tolerated; and considerations of greater and lesser evil come into play in deciding which opinions should remain unpunished.
(Bejczy, “Tolerantia: A Medieval Concept,” Journal of the History of Ideas 58:3 : 365-384.)