Galen’s eclectic medical education exposed him to some of the most prominent medical sects of his day. He sought out the best each could offer, but was firm in his conviction that strict adherence to any one methodology was a form of intellectual servitude:
Galen wrote vigorous appraisals of and attacks on diverse medical traditions, but while he was critical of everyone, he was harder on some schools of thought than he was on others.
Galen received some of his earliest medical training from Empiricist doctors in Pergamon. The Empiric school, rooted in the belief that knowledge could be gained from empeiria (experience) through observation, had its origins in ancient Greece but continued to develop during the Roman period. Although only fragments from the Empiricists have come down through time, the majority of those texts describe therapeutics: if a cure was observed to be successful, then that cure should be repeated. The reason behind the healing was less important to the Empiricists than the outcome; in fact, they doubted that the causes of diseases or the reason that treatments worked could ever be known. Cures might result from treatment based on experience, treatment prescribed by a dream, and even accidental good fortune, or some other way—and occasionally the treatments can seem naïve or downright outlandish (we read of a cure for rabies, delivered in a dream, made from crayfish collected by moonlight on a single night). But the idea that doctors should observe patients, study case histories describing other doctors’ observations, and treat symptoms using previously successful methods provided Galen with key insights. It is also at the core of our contemporary approach to reproducible clinical studies (by moonlight, at “warp speed,” or otherwise).
Galen was explicit in his opinion:
He credits the school with teaching him how to read pulses, follow fevers through “critical days,” and other important medical discoveries, but there were aspects of their approach that he found problematic. For the Empiricists, theorizing why someone became ill or how a medication worked was seen as irrelevant—a view with which Galen disagreed. But he most vehemently opposed their rejection of dissection: the Empiric school believed direct observation of wounds was sufficient to achieve anatomical understanding, and Galen wrote more than one scorching critique of this position.
There were other medical sects that also valued observation of evident, physical phenomena but regarded it as secondary to theoretical knowledge. The Dogmatist (also known as Rationalist) school frequently used the same treatments as the Empiricists, and Galen had “no hatred” against the Dogmatists either. But unlike the Empiricists, the Dogmatists prioritized deductive reasoning based on physical and metaphysical theories of the body to arrive at their conclusions. Though united by an attempt to apply principles of causation to medicine, the label “Dogmatist” encompassed groups from differing traditions and using a spectrum of theoretical approaches. Pneumatists, for example, touted the overwhelming importance of breath moving through the body, while Erasistrateans controversially believed that the arteries contained only air.
Galen praised the Dogmatists’ interest in anatomy, which the Empiricists disdained, but was critical of what he perceived as their reductionist approach. According to Galen, the Dogmatists privileged their objective view of biology (rooted in observed anatomical study) above the patient’s own subjective experience. He frequently found the resulting explanations of illness too distant. As with the Empiricists, Galen maintained his independence from these thinkers but took the best the Dogmatists had to offer. He used deductive reasoning in his own practice, albeit in a more balanced way that accounted for patients’ individual cases.
Of all the medical sects of his day, none was held in greater contempt by Galen than Methodism. The Methodists (unrelated to the modern Protestant denomination) understood the human body to be made up of atoms that circulated through pores; when the normal movement of these elements was disrupted, illness resulted. Disease thus occurred when the pores in the body were too constricted, too relaxed, or some combination of the two. It was a radically simplified view of the body and illness—the Methodists rejected experience, anatomy, and all other medical approaches—and Galen had no kind words for them. He attacked their prescription for fevers (an extended fast) and mocked their three-day unit of treatment. The Methodists even claimed, to Galen's rage, that medicine could be taught in only six months.
Our understanding of Methodism, however, rests overwhelming on Galen, who is an unabashedly hostile and perhaps an unreliable witness. He directed many of his attacks toward the movement’s founders and historical figures—Asclepiades of Bithynia, Themison of Laodicea, and especially Thessalus of Tralles—but he ridiculed his Methodist contemporaries too, calling them “Thessalian asses” (after Thessalus of Tralles) and other unpleasantries. The frequency and vehemence of his attacks suggest that Methodism was an influential medical sect in the second century CE—it appears to have made inroads in elite circles, and the noblewoman and (briefly) Empress Annia Faustina traveled with a Methodist physician in her retinue. Indeed, Soranus of Ephesus, a Roman doctor widely renowned for his gynecological writing and the only self-professed Methodist whose work survives, shows us Methodism in a far more reasonable light.
In practice, there were more than three medical sects. The actual healing landscape in the Roman Empire was complex, and within these groups one could find competing and overlapping subsects. But an overview of these schools provides us with a sense of the different ways that Romans conceived of the body and healing. Other ancient writers in addition to Galen—the Latin medical writer Celsus (ca. 25 BCE–ca. 50 CE), for instance—have also described these same broad divisions. The voluminousness of Galen’s texts, and the uneven survival of primary sources from the Empiricists, Dogmatists, and Methodists themselves, means that much of our knowledge of these practices comes from Galen.
His critiques thus shape our understanding of all of Roman medicine, especially because he frequently wrote to showcase his own superior skill and thought. Although Galen avoided identification with any single sect, he did see himself as part of a larger medical tradition: his hero was Hippocrates.