Accidentally on Purpose
Aristotle, Aquinas, and the enigmas of transubstantiation
Aden Kumler
In his Dialogue on Miracles, the thirteenth-century Cistercian monk Caesarius of Heisterbach describes an unexpected event that occurred during an otherwise routine celebration of Mass in the village church of Buschbell near Cologne. As the parish priest began to consecrate the Eucharistic host, or communion wafer, that would be transformed into Christ’s body, the wheaten disk jumped off the paten, the little dish in which it had been placed upon the altar. Thinking that this was some accident of how the host had been situated, the priest tried again. Again, the host leaped from the paten, evading consecration. A third time the priest attempted to perform the ritual, and yet again the host jumped away. Seeing this, the priest was terrified. As a final resort, he had an assistant select a new communion wafer, which he was able to consecrate without incident.
But clearly the parish priest’s mind was troubled. Rather than forgetting the whole incident, he opted to take the hyperactive wafer to the priors of the church of the Holy Apostles in Cologne, hoping that these learned men could get to the bottom of things. They too were amazed, until one of their number, holding up the troublesome host to the light, perceived a dark spot within its round white form. Breaking the host, he discovered a louse baked within it. All the assembled clerics marveled: clearly the holy angels had intervened in the little parish church. The seemingly freak occurrence of the jumping wafer was in fact a case of supernatural quality control: it would not have been acceptable to consecrate Christ’s human and divine body from such a bug-infested host. Concluding this story, Caesarius adds his own snarky aside: “Alas! How inattentively communion wafers are made by the wives of bell ringers nowadays; it is inevitable that this kind of negligence will occur.”[1]
For the parish priest attempting to fulfill his obligation to celebrate Mass, the communion wafer’s jumping about was an unexpected event, disrupting the normal course of things, but, as the story’s denouement drives home, it was no accident in the modern sense. Caesarius includes the case of the leaping host as one of a series of miracle stories about the Eucharist, and that frame for the tale—it reports the aberrant action of not any old thing, but the Eucharistic host itself—makes it very much a story about accidents as Christians in the Middle Ages knew them.
In the Latin jargon of medieval theology, accidentiae referred to the persistent, empirical appearance of the bread and wine transformed in the Mass into the Eucharist, the sacrament of Christ’s body and blood. Although learned texts, popular religious instruction, liturgical performance, and Holy Writ taught Christians that the bread and wine consecrated by priests were really changed into Christ’s flesh and blood, the testimony of the human senses contradicted this article of belief. With the Eucharist, what you saw was emphatically not what you got. Encountering the sacrament of the altar, devout Christians were urged to look, to taste, and to believe despite what their senses reported. Their salvation depende