Fascination among theologians and philosophers, Middle Ages to Renaissance
Thomas Aquinas, Marsilio Ficino, Leonardo Vairo and Francis Bacon: how learned European culture tried to explain the power of the envious gaze.
The evil eye was not only a popular belief. For centuries physicians, theologians and philosophers seriously asked whether the gaze could do harm, and how. The key word was fascinatio, inherited from classical Latin, and the debate drew on Aristotle, on Pliny, on the Church Fathers and on Arabic medicine. Following this debate means discovering how an ancient fear was translated into the language of the science and theology of the time.
Thomas Aquinas and the clouded mirror
In the Summa theologiae, in the first part, at question 117, Thomas Aquinas asks whether the human soul can change the matter of external bodies. Replying to an objection, he discusses fascination itself. He takes from Aristotle an observation then held to be true, according to which the gaze of a menstruating woman would cloud a mirror, and he infers from it that the eyes can alter the surrounding air.
From this Aquinas explains that a soul moved by strong malevolence can infect the eyes, and through them the air, until it harms the most delicate bodies, such as those of children. It is a natural explanation, not a demonic one: the theologian distinguishes this mechanism from the intervention of the devil, which he deals with elsewhere. His authority ensured that fascination long remained a legitimate subject in the schools and universities of Europe.
Ficino and the spirits that issue from the eyes
In the fifteenth century the Florentine philosopher Marsilio Ficino took up the theme in a Platonic key. In his commentary on Plato's Symposium, known as De amore, he explains falling in love as a true fascination: subtle spirits, vapours of the blood, issue from the beloved's eyes, enter the lover's eyes and transform him. The same mechanism, reversed, could produce the harm of envy. Love and the evil eye thus became two faces of a single physiology of the gaze.
Treatises and essays of the early modern age
In 1583 the Benedictine Leonardo Vairo, later bishop of Pozzuoli, published De fascino in three books, one of the first treatises devoted entirely to the subject. Vairo gathered ancient and modern testimonies and set them within a theological framework, giving considerable weight to the action of the devil. The work was reprinted and remained for decades a point of reference for anyone who wished to tackle the question with the tools of Catholic doctrine.
A few decades later Francis Bacon, in the essay Of Envy included in the enlarged 1625 edition of his Essays, observed that envy seems to involve something like an «irradiation of the eye». The English philosopher did not commit himself with certainty, but he recorded the belief as something deserving attention, a sign that the subject had kept a certain intellectual dignity even on the threshold of modern science.
This long season of treatises explains why, in the eighteenth century, Neapolitan jettatura could be discussed by jurists and men of letters with a mixture of erudition and irony. The arguments were ready to hand: the visual spirits, the infected air, the examples from Pliny. Popular and learned culture, far from being separate, exchanged images and explanations of the same fear for centuries, adapting them each time to the knowledge of their own age.