Pietro d'Abano

← Encyclopedia

Pietro d’Abano was an Italian physician, philosopher, and astrologer of the late thirteenth and early fourteenth centuries, remembered both for a serious attempt to reconcile medicine with natural philosophy and for the darker reputation that grew up around his name after his death. He was born around 1257 in Abano, near Padua — a spa town long famous for its hot mineral springs, the kind of place where the healing properties of the natural world were taken as plainly evident — and the name of the town followed him into his books and into his legend. He studied abroad, in Constantinople and then in Paris, and spent his working life as a physician and teacher at the University of Padua, then one of the great centers of medical learning in Europe, a studium where medicine and philosophy were taught together and where the boundary between the two was deliberately thin.

The years in Constantinople matter to the shape of what followed. There he gained a command of Greek rare among Western scholars of his day, and worked directly with Greek texts — of Aristotle, of the physicians, of Ptolemy — rather than at the second remove of Latin versions made from Arabic. He is credited with translating Greek medical and astrological works into Latin, and his access to the originals gave his teaching an authority that those who knew the material only in translation could not match. From Constantinople he carried the Problemata attributed to Aristotle into Latin, supplying it with a commentary; he rendered astronomical and astrological matter, and was associated with the diffusion of the works of the Jewish astrologer Abraham ibn Ezra into the Latin schools. He moved in the world of Michael Scot and the other translator-philosophers who carried Greek and Arabic science into Latin Christendom — figures whose learning, drawn from infidel and pagan sources, made them suspect even as it made them indispensable.

The stream he drew from was the same stream that carried the Arabic Hermetica — the bodies of astrological, talismanic, and natural-philosophical lore that reached the Latin West through Arabic intermediaries and that mixed Greek learning with Hermetic and star-craft material the schools could neither wholly digest nor wholly disown. To work this material was to stand where medicine, astronomy, and the suspect arts met, and a man who worked it freely — who knew the texts in their own tongue and cited them without flinching — made himself a target for the same reason he made himself useful. Pietro’s Greek was, in this, both his armor and his exposure: it lifted him above the herd of Latin compilers and set him among the handful of Westerners who could check the authorities at their source, and it tied his name to a learning the Church watched with a narrowed eye.

The Conciliator

His major work, the Conciliator differentiarum philosophorum et praecipue medicorum — the “Reconciler of the differences between philosophers and especially physicians” — is the book on which his standing as a man of science rests. Composed over years and revised around 1310, it survives in many manuscripts and was printed repeatedly from 1472 onward, becoming one of the most reprinted medical works of the early age of print. Its design is the design of the scholastic classroom raised to the scale of a whole discipline. Pietro set out more than two hundred differentiae — disputed questions on which the authorities of medicine and of natural philosophy contradicted one another — and worked through each in the formal manner of the schools: the question stated, the arguments on either side marshaled, the conflicting authorities cited, and then a conciliatio, a reconciliation, in which the apparent contradiction is dissolved by drawing a distinction or fixing the sense in which each side spoke truly.

The questions themselves range across the whole of medical theory and the natural philosophy that underwrote it: whether medicine is a science or an art, how the elements and the four humors compound into the body’s complexion, whether the heart or the brain holds primacy in the organism, how generation proceeds, what the celestial bodies contribute to health, how the soul relates to the body it animates. On each, the authorities had spoken differently — the Greek physicians one way, the Arabic commentators another, Aristotle a third — and the work of the Conciliator is to show that the disagreement is apparent, not real. The point was not to choose a winner. The point was to show that the masters did not, rightly understood, disagree — that Aristotle the philosopher and the physicians could be held in one coherent system, and that where the texts clashed the fault lay in the reading rather than in the truth. The method was Aristotelian and the materials were largely Arabic: Pietro worked from the Greek medical corpus by way of Avicenna and the Arabic commentators, the great mediators through whom Galenic medicine reached the Latin West dressed in the logic of Aristotle. His confidence in the powers of nature, the heavens, and unaided human reason placed him close to the Averroist philosophy then under suspicion in the schools — the view that natural causes reach further than the theologians liked to allow, and that the philosopher’s demonstrations have a standing of their own. He pressed that confidence to the edge: he offered natural explanations for events others reserved to the miraculous, and held that the order of nature was tight enough to account for much that piety preferred to attribute to direct divine intervention.

The book’s afterlife measures its weight. From its first printing it became a fixture of medical instruction, set before students at Padua and beyond, debated and excerpted and reprinted into the seventeenth century — so that long after the trials, long after the legend had hardened, working physicians still learned their disputed questions from a man the Church had condemned. The Conciliator gave them a method as much as a doctrine: a way of holding contradictory authorities in a single frame without surrendering any, the scholastic art of reconciliation applied to the body. It is the durable Pietro, the one the legend never managed to bury.

Alongside it he wrote the Lucidator dubitabilium astronomiae, a treatise sorting the doubtful questions of astronomy and astrology, and a body of commentary on the medical and astrological texts he had brought west — among them his work on the Problemata and his Latin renderings tied to the astrological writings circulating under the name of Abraham ibn Ezra. The range is the range his age expected of a complete physician — for Pietro held, with much learned medicine of the time, that the good doctor must also be a natural philosopher and an astrologer, since the body could not be read apart from the cosmos that bore upon it. Medicine, philosophy, and the science of the stars were for him a single discipline with three faces, and to amputate any one was to practice the others blind.

Medicine under the stars

Threaded through the medicine was astrology. Pietro held, as the dominant learned medicine of the age held, that the movements of the heavens bore on the body’s complexion, on the onset and course of disease, and on the times at which a remedy would take or fail. The physician who ignored the stars was working half-blind. This was not, in his frame, an intrusion of the occult into healing; it was natural philosophy at its most rigorous — the recognition that the sublunary world of bodies is governed by the great moving bodies above it, that the influence of sun and planets is as real and as lawful as the influence of heat on water. The heavens act on the earth by light and motion and quality, not by spell. To cast a nativity or to choose the hour for a treatment was, to him, to read a causal order, not to bargain with spirits.

That distinction — natural celestial influence on one side, the trafficking of spirits on the other — is the distinction on which a man like Pietro staked his respectability. It is also the distinction that his accusers, and later his admirers, would refuse to keep. The same doctrine that made him a serious natural philosopher in his own eyes made him, to a suspicious reader, a man who bound the world to the stars and reached past the licit edge of inquiry. The talisman and the amulet — objects that drew or deflected celestial virtue — lay just over the line that astrological medicine drew, and a generation inclined to see sorcery everywhere did not trouble to police it.

The Inquisition and the two deaths

That edge is where the historical man becomes a legend. Pietro was brought before the Inquisition on charges that touched both heresy and magic — that he had denied the soul’s immortality or the reality of demons, that he had reduced the miraculous to nature, that he practiced or taught forbidden arts. The surviving record is thin and partly contradictory, but the standard reconstruction, set out in Lynn Thorndike’s history of medieval science, holds that he was proceeded against more than once, and that he died around 1316 — before a final sentence could be passed, by the most credible accounts in the course of the trial rather than after it.

The trial did not end with his death; that is the strange afterlife of the case. Later report held that the proceedings continued against the dead man, that he was condemned posthumously, and that his bones were ordered exhumed and burned — the standard fate of a convicted heretic denied to the living defendant, carried out, by one account, on an effigy when the body itself was hidden away by his friends. Whether the burning happened as told or grew in the telling, the verdict attached itself to his memory with a permanence no acquittal could have prevented. A man tried twice for magic and burned in effigy after death is no longer only a physician.

What drove the charges is harder to fix than the fact of them. Some of it was doctrine — the natural-causes program that explained away miracles, the Averroist leanings, the cosmos so tightly bound by celestial law that little room was left for the freely intervening will of God. Some of it was the ordinary malice of a learned town, where a famous and well-paid physician collects rivals as readily as patients, and where the accusation of magic was a weapon ready to any hand. The two are not separable in the record, and probably were not separable in life: the man whose learning ran ahead of his age was exactly the man whose enemies could make that learning sound like sorcery. The particular charges that come down — that he kept the seven liberal arts as seven familiar spirits in a glass, that he could call back the money he had spent — belong to the legend already, accreted to the trial rather than drawn from it.

Two Pietros

The two Pietros are worth holding apart. The first is a documented figure in the history of medicine and in the transmission of Greek and Arabic science to the Latin West — a Greek-reading translator, a master of the disputed question, an astrological physician whose celestial doctrine was of a piece with the natural philosophy of his time, and a teacher whose Conciliator shaped medical training for two centuries after his death. (He is not to be confused with Pietro Pomponazzi, the later Paduan Aristotelian of the sixteenth century who likewise argued that natural reason left the soul’s immortality unproven and the wonders of the spirits explicable by nature; the resemblance of position across two hundred years is genuine, but they are two men.)

The second Pietro is the magus of legend, assembled partly by his accusers and partly by later occultists who found a useful patron in a physician the Church had feared. By the time of Renaissance magic, his name had become a byword for the learned magician, invoked by Pico della Mirandola, by Trithemius, and by Cornelius Agrippa as one authority among the masters of the high art. To call a book his was to dignify it. And so the Heptameron — a compact handbook of angelic and planetary conjuration, organized by the days of the week and their ruling powers — came to circulate under his name. It is almost certainly a later composition rather than his own work; its appearance in print in the sixteenth century, bound with the spurious Fourth Book attributed to Agrippa, gave it the authority of a famous name and a settled place in the ceremonial-magic literature. Through it Pietro took a permanent station in the grimoire tradition as a supposed master of conjuration — a fixture of the literature of the conjured spirit that runs alongside the older Latin currents of divination — his medicine and astronomy forgotten and his name reduced to a signature on a book of spirits he never wrote.

Texts and scholarship

The Conciliator is the surest ground. Composed in the first decade of the fourteenth century and revised about 1310, it was first printed at Mantua in 1472 and then many times over, the great Venice editions of the early sixteenth century carrying his medical system across Europe; the Lucidator dubitabilium astronomiae preserves his astrological-astronomical method in the same scholastic form. The modern reconstruction of the man, against the legend, was done above all by Lynn Thorndike, whose A History of Magic and Experimental Science (New York: Columbia University Press, 1923) devotes a long chapter to Pietro and remains the standard English account, weighing the documented career against the accreted reputation. The biographical outline, the dates, and the trial tradition are summarized in the standard reference notice (Wikipedia). The pseudonymous Heptameron and its place in the printed grimoire tradition — its first appearance bound with the Fourth Book of Occult Philosophy attributed to Agrippa — are documented, with the early editions and the question of attribution laid out, in Joseph H. Peterson’s critical apparatus on the esoteric archives (Esoteric Archives).

The reputation outran the man, as it often did for those whose learning ran ahead of what their age could comfortably name.

→ Related: Michael Scot · Ptolemy · Apollonius Of Tyana · Divination · Middle Ages · Avicenna · Aristotle · Scholasticism · Astrology · Ceremonial Magic · Renaissance Magic · Cornelius Agrippa · Arabic Hermetica · Talisman · Amulet · Magic