Disease and Prediction: Hippocratic Musings in the Time of COVID-19
Ἐς δὲ τὰ ἔσχατα νουσήματα αἱ ἔσχαται θεραπεῖαι … κράτισται.
Extreme remedies are most appropriate for extreme diseases (Hippocrates, Aphorisms 1.6)
As the novel coronavirus keeps spreading around the world, many questions burn in people’s minds: will the epidemic hit my area? And when? How many cases and deaths will there be tomorrow, or in a week, or in a month? How likely am I or a loved one to get sick?
Such unprecedented uncertainty fuels anxiety and panic, already rampant in media outlets and society at large. While practicing social distancing and self-isolation, scholars have already started meditating on what the ancients can teach us about how to cope with the challenges and uncertainty of a global pandemic.
While it is difficult to keep misinformation and unfounded claims at bay regarding the present situation, the more scientifically savvy and alert turn to mathematical models and network analysis in an effort to follow the exponential and logistic growth of the epidemic and come up with reliable forecasts on what is next.
The most effective remedies, it seems, do not merely involve reacting to the circumstances, but also — and crucially — predicting the development of the situation to avert its most disastrous consequences. If there is anything that the COVID-19 emergency can make us reflect on, a good candidate would be the ability of human science to predict the future.
The issue was far from unknown to ancient scientists. In Classical Athens, in particular, writers and practitioners of medicine found themselves embroiled in a curious yet illuminating debate on the extent of their predictive abilities and the medical art’s relationship with one of its historical brother-enemies: divination.
Greek doctors and seers — two categories of specialized technicians— often find themselves vying for the same territory. After all, both appeal to patients in the grip of anxiety and uncertainty, and both interpret present signs to formulate predictions about the future. This is why some Hippocratic authors, writing between the late fifth and the early fourth century B.C.E., saw divination and their practitioners as dangerous competitors.
Medical authors themselves emphasize the need to make predictions: the Hippocratic Prognostic begins by stressing the importance for the physician to practice prognostication, πρόνοια, especially due to its invaluable role in reinforcing the patient’s trust in the doctor.
The Greek word πρόνοια is, of course, older than Hippocratic medicine, and has a range of meanings from ‘foresight’ and ‘foreknowledge’ to ‘prediction’ and, above all, oracular ‘prophecy’. In later antiquity, Macrobius remarks on the prophetic style used in the opening of the Prognostic, noting its similarity with an epic formula denoting divinatory powers:
siquidem medicinae atque divinationum consociatae sunt disciplinae. nam medicus vel commoda vel incommoda in corpore futura praenoscit, sicut ait Hippocrates oportere medicum dicere de aegroto τά τε παρεόντα καὶ τὰ προγεγονότα καὶ τὰ μέλλοντα ἔσεσθαι, id est “quae sint, quae fuerint, quae mox ventura sequentur”. quod congruit divinationibus quae sciunt τά τ’ ἔοντα τά τ’ ἐσσόμενα πρό τ’ ἐόντα.
Indeed the disciplines of medicine and divinations are allied. For the doctor knows beforehand what pleasant or unpleasant things will occur in the body, just as Hippocrates says that about a sick person the doctor ought to speak “the things are happening, and have happened, and are going to follow.” Which is appropriate for divinations, which have knowledge of ‘things that are and are to be and were before.’ (Saturnalia 1.20.5)
Macrobius’s first Greek quotation is from Hippocrates, the great medical writer; the second is from Homer, about Calchas the seer.
Despite vigorous disagreement over what counts as a scientific inference and what grants medicine its scientific status, none of the known Hippocratic authors express doubts over whether prediction itself is a fundamental part of the doctor’s job. What is more, ancient doctors do not hesitate to borrow keywords from the language of divination when they talk about prognosis.
Medical prognosis, in the Hippocratic tradition, is the predictive evaluation of signs observed in the patient’s body, and the attribution of value to such phenomena insofar as they can indicate the course of a given condition and thereby lead to inferences crucial to the patient’s recovery.
Like the seer, the physician analyzes the observed omen in order to provide a prognosis which influences future action. According to a Hippocratic source, however, while both seers and physicians are capable of making predictions later proven true, the doctor can explain the reasons why this happens and the diviner cannot. In short, medicine may well be a fallible and conjectural art of prediction, but its procedures are far from haphazard.
Correspondingly, Hippocratic writers appear consistent with one another in rejecting any substantial identification between the two competing crafts of medicine and divination: this is particularly clear in On Dreams, On the Sacred Disease, the Prorrhetic, and Regimen in Acute Diseases.
Yet their effort to define medicine itself in contrast with the mantic art testifies to a widespread belief in their affinity, which must have permeated Greek society well into the fifth century and beyond (literary examples of the mantic-medicine juxtaposition abound: from Aeschylus to Aristophanes and Plato). In sum, the medical and the divinatory craft appear to encroach on each other: success in both arts hinges upon making accurate forecasts.
Thus, Galen — who managed to survive the Antonine plague, now estimated to have killed around five million people— boasts about his forecasting skills in his treatise On Prognosis, where he also relates his detractors’ accusation that his medical triumphs were due to divination and magic. For many ancient Greeks, it seems, seers and physicians have more than a few things in common.
This somewhat bizarre cultural phenomenon can perhaps acquire a new connotation during the 2020 COVID-19 pandemic. In fact, the mantic-medicine analogy reflects an ancient question that our time has brought into the foreground: can science predict the future?
The Hippocratic debate on prognostication in medicine points in a clear direction: the virtually inevitable fallibility of scientific predictions concerning natural phenomena is not a valid argument to abandon the predictive effort itself (let alone assimilate it to quackery or charlatanry).
In the second century C.E., this line of reasoning leads Galen and his contemporary Alexander of Aphrodisias to elaborate the notion of “stochastic craft”: according to them, success in medicine ought to be evaluated based on process criteria rather than final outcomes (not bad to keep that in mind when facing a previously unknown disease with no available cure, right?).
Similarly, any failures in prognostication are due to the nature of the phenomena under observation, which are influenced by unpredictable external forces. This, however, does not justify giving up on prognostication itself.
On the contrary, one must continue refining the available predictions based on an ever more sophisticated collection of evidence. Prediction, after all, is the only antidote to uncertainty that science can offer.
As the case of COVID-19 has dramatically shown, any scientific prediction is only as reliable as the data it rests upon. What is more, it may not be immediately obvious what categories of data are the most relevant: for instance, focusing on reported actual cases runs the risk of shifting attention away from the range of estimated actual cases, which is arguably a more important number.
Indeed, predictions can be dire: yet one wonders whether—like the Trojans—we might end up regretting our refusal to believe Cassandra. So far, numerous countries affected by COVID-19 have faced the issue of reacting to an emergency situation, rather than taking preemptive measures to avert it. Not to mention the difficulty of making public health decisions (such as putting an end to social distancing and other restrictive measures) without widespread testing and data gathering.
Recent research on Greco-Roman medicine has convincingly illustrated that ancient science’s most significant insights for the modern world lie not so much in specific techniques or practices as in the broad-ranging questions that ancient scientific writers asked of themselves and their bodies of knowledge.
In times of great uncertainty such as those we are experiencing, the need not to forget the stochastic and infinitely perfectible nature of scientific prediction is an ancient warning we can only ignore at our peril.
Marco Romani is Director of European Operations for the Paideia Institute. Besides opera and theater, he has a particular passion for the history of science and medicine.
