§3. Philosophers and Physicians

Theories of disease in Hippocratic texts are not entirely original with these doctors, and Michael Frede observes, “It was the philosophers who started medical theory.” Pythagoras seems to have been decisive, formulating the first physiological thesis when he explained disease as a disordered harmony of bodily constituents.

The philosopher as healer is an early Pythagorean tradition, with legends of Pythagoras and Empedocles as itinerant healers. Alcmaeon of Croton is another early figure, from the early fifth century, two or three generations before Hippocrates. He was a natural philosopher interested in physiology and medicine. He traced all the senses back to the brain, which he regarded as the seat of intelligence, making probably the first statement of cognition’s cerebral localization, which became the Hippocratic view, as well as Plato’s. Others, including Empedocles, Aristotle, and the Stoics, localized mind and feeling in the heart. Alexandrian physicians finally settled the matter in the third century bce with anatomical proofs of cerebral localization.¹³

An ancient source describes Alcmaeon as a Pythagorean, and like Pythagoras he explains health as a harmonious blend (summetros krasis). He innovated in defining the harmony as one of opposite qualities, especially hot/cold and dry/moist. Disease is produced by the domination (monarchia) of one of these opposites, preventing the partner from playing its part.

Alcmaeon innovated a style of proof that would become a staple of med­ical tradition down to modern times, and a model of experimental reasoning. “The gods have certainty (sapheneia) concerning non-evident matters, but it is given to men to conjecture from signs (tekmairesthai)” We discern the in­visible by the artful use of visible signs. It may seem trite, but in its time it was sublime. A whole new reason emerges to pay attention to nature and especially its changes. With an instrumental use of perception, seeking perceptible signs of unperceived causes, knowledge can colonize beyond perception.¹⁵

A generation later, Empedocles introduced a theory of four elements (earth, air, fire, and water). Bodies in nature are each a slightly different blend, having an individual nature. The idea becomes important in medicine, where it underwrites the recommendation to adjust therapies to patients, which requires investigating and qualitatively assessing their individuality. Empedocles had the reputation of a physician and was remembered for eliminating plague at Solinus. He developed early theories on respiration, embryo growth, nutrition, sleep, and the senses, and several disciples were physicians. Empedocles is associated with a Sicilian medical tradition, whose signature ideas include the pneuma, or vital breath, as an invisible corporeal fluid physiologically on par with blood; innate heat as the energy of physi­ological processes, including embryonic development and digestion; respi­ration as the coolant of innate heat; blood as a product of the liver and the agent of nutrition; and semen and milk as byproducts of surplus nutriment.

Primitive as early physiological thinking may seem, it breaks new ground, and prepares people to regard such matters as suitable for inquiry. Medicine had always been a difficult art with an uneven chance of success. After the innovations of these philosophers, however, practitioners came to view the difficulty of medicine as due to inadequate knowledge, including practically no understanding of the body's interior parts and functions. For the first time in history, medicine and the problems of health and sickness came into focus as problems of ongoing research and empirical (as opposed to traditional or revealed) knowledge. Formal centers of medical instruction had appeared by the mid-fifth century, yet the art proved unexpectedly difficult to advance. Some of these doctors linked their techne to a new idea about civilization and progress that encouraged taking long views.

According to the new account, the technological achievements of civili­zation are of relatively recent origin. Human life used to be far simpler and materially poorer than it is now. This idea contested and soon displaced the older thought in Hesiod of a past golden age. Many ancient authors told versions of the new account, but they seem to be variations on what is prob­ably one source, the late fifth-century atomist Democritus (§9). In our ear­liest condition, people lacked fire, shelter, clothing, and reliable food. Then came the first rudimentary steps toward civilization, including living in caves and gathering foodstuffs. A series of discoveries followed, including fire, clothing, speech, and law. These enabled more complex innovations, in­cluding the use of metals, tools, and the division of labor. The most recent additions were hedonistic arts like astronomy, music, and wrestling.

Each step in the advance was merely suggested by accidental incidents. The discoveries are naive and empirical—a lucky observation like seeing lightning strike a tree and create fire, or a naive analogy like garments of an­imal skin.

Greek doctors might be expected to approve this theory. Hesiod said that humanity was given techne by Prometheus in compensation for mortality and the wrath of Zeus, but in the argument of Democritus our ancestors found these arts themselves and not that long ago. They were discovered under the pressure of necessity and worked to advance humanity’s power of choice within limits set by necessity. We can help ourselves, for which we need knowledge of our nature and commensurate technical arts, rather than prayers and sacrifices to the gods. That was also how Hippocratic doctors understood their art, and why they were optimistic about discoveries and progress. One of them admonishes readers:

The ancient art of medicine should not be rejected as non-existent or not well investigated because it has not attained exactness in every item. Much rather, since, as I think, it has been able to come close to perfect exactness by means of reasoning where before there was great ignorance, its discov­eries should be a matter of admiration, as well and truly the results of dis­covery and not chance.¹⁸

Hippocratic authors, or some of them, insert medicine in Democritus’s philosophy of history. The art of medicine arose rather late, but it has already accomplished a lot and can be expected to improve. Other doctors ally them­selves with the rising prestige of logos, having reasons, knowing causes, and affirm the value of such “theoretical” knowledge in medicine. They are the so-called rationalists (logikoi), the first use of this expression in European tradition. Medicine should be a field of scientific knowledge. A physician not only cures; he knows the cause, the scientific explanation, of the disease. In the words of the Hippocratic Techne, “It belongs to the same skill to know the causes of disease and to understand how to treat them with all the treatments that prevent disease from growing worse.” Another Hippocratic author writes, “If someone knows the cause of disease, he will be able to administer what is beneficial for the body.”¹⁹

For these logikoi, experience and healing competence are not enough for medical expertise.

Other Hippocratic texts disdain these “hypotheses” and caution physicians to consider only what is established by experience. The author of Ancient Medicine denounces physicians “tending toward philosophy” in their way of explaining their view that one must have complete knowledge (katamathein) of what a human being is in order to treat people medically. These opponents think that “whoever does not know what a human being is cannot know the science of medicine—no, anyone who is going to give correct medical treat­ment... must have a complete knowledge of that.”²¹

The objectionable theories import explanations from the cosmology of the philosophers. The problem is not that these ideas are unproved, rather that they are too aloof from the level at which physicians encounter patients. It is no good being told that a certain food is “hot.” Different substances are “hot” or “dry” in different ways. Everything depends on how the hot is blended and prepared. “There are many other things that are hot and that have dif­ferent and contrary powers to one another.” No theory of elements helps the physician select the correct hot or dry for a given patient.

The word “hypothesis” will haunt natural philosophy for the next two thousand years. Is the use of hypotheses good, an instrument of knowledge, or contrary to good method? Are they inevitable, or should they be elimi­nated wherever possible? The Greek word is first attested in Ancient Medicine, where it is used to denounce doctors who want to deduce medicine from a philosophical theory.

[Those who] having undertaken to speak or write on medicine have first laid down for themselves some hypothesis to their argument, such as hot, or cold, or moist, or dry, or whatever else they choose... are all clearly mistaken in much that they say; and this is the more reprehensible as relating to an art which all men avail themselves of on the most impor­tant occasions.... Wherefore I have not thought that it stood in need of an empty hypothesis.²³

Scholars say the word hypothesis is not used here in any previously estab­lished sense. The basic meaning of the verb from which the noun derives is to place underneath, or lay down, as a basis for development of some kind. The “hypotheses” Ancient Medicine reproves are poetical inventions or merely plausible accounts, which are unavailing in medicine, where the knowledge required is more specific and concrete. Cosmological inquiry is necessarily “hypothetical.” That is not objectionable—in cosmology. But it is unsuited to medicine. In cosmology nothing clearly distinguishes true theory from mistakes, but medicine has a standard that the philosophers do not care to use. The Hippocratic author explains that this standard (metron) is “the perception of the body” (to somatos ten aisthesin), meaning the physician’s perceptions. These provide clear knowledge of medical causes and effects, rendering hypotheses fetched from natural philosophy superfluous.²⁴

The author of this work is notably acute on the topic of causation. The idea of the cause as something comprehensively necessary and sufficient for the effect begins in Ancient Medicine. “We must securely consider the cause (aitia) of each complaint to be those things (tauta) the presence of which of necessity produces a complaint of a specific kind, which ceases when they change into another combination.” A scholar of this material describes the statement as “the clearest, the most general, and the most conceptually pre­cise idea of causality to be found in fifth-century thought.”²⁵

Ancient Medicine explains the origin of the physician’s art. At first, before medicine, the people made the essential discoveries for health by themselves. These concern diet, and the beneficial effects of correct blending and pre­paring. As diets improved, so did health. Then they were surprised by a new observation. It became clear that people sometimes got sick even with a well- prepared diet, which prompted the first medical investigations, as doctors devoted themselves to figuring out what dietary and other practices would restore health. Their investigations followed the same ancient method by which the healthy diet had been discovered, building on what was already known about foods and digestion. In other words, the first medicine was al­ready adhering to the ancient way.

Their method was empirical, as later commentators pointed out, although “empirical” was not yet part of medical vocabulary. Hippocrates does in­deed insist on the need for careful, detailed observation of various foods, drinks, baths, and so on, and their effects on different people under different circumstances, contrasting this aspect of medicine’s ancient method with the innovations shortsighted physicians are keen to import from cosmology. But the medical philosophy of Ancient Medicine is not truly consistent with that of the later Alexandrian Empiricists who appropriated it for their polemic.

For instance, the Hippocratic author allows theoretical, causal reasoning, as in his claim that the discoveries of ancient medicine came about through logismos, which he contrasts with discoveries by chance (tuche), the antith­esis of techne; and he allows hidden, theoretical entities in medical explana­tion, provided they are controlled by observation, as in his explanation that foods possess an unseen “strength” that needs to be tempered by separating and blending. The author also explains that untempered foods do harm be­cause their excessive quality causes the body to secrete more of the same quality from its own mass, an inference from unseen causes to unseen effects that amplify visible symptoms.

All of this flies in the face of the Alexandrian principles of empirical medi­cine (§4). But even if Ancient Medicine is not much in sympathy with the pro­gram of the later Empiricists, there is concurrence on one point, which is that rationalism must be opposed. What Ancient Medicine denounces is when doctors set aside generations of painstaking experience, and commence medical analysis from plausible-sounding ideas about life and the cosmos— mere hypotheses. That is the tendency of what will eventually be called “ra­tionalism,” and it is the target of this first denunciation of “hypotheses.”

But the work is more than a denunciation, as it also offers alternative direc­tion. The best way to link medicine and philosophy does not start with phi­losophy and deduce medicine, but the reverse. Use the methods of medicine to investigate the human constitution, its health and disease, and from there work out to a natural philosophy that keeps the human mind and body in the center of the natural order it studies. One must investigate so many things that the knowledge of medical science eventually extends to knowledge of the entire cosmos. Medicine is not a branch of science, it is a different philo­sophical idea of what a science of nature is and how to pursue it, in contrast to either Plato or Aristotle. This is where ancient medicine begins to unfold an empiricism that is a philosophy of nature rather than an epistemology.

Socrates asks Phaedrus, “Do you think that one can acquire any appre­ciable knowledge of the nature of the soul without knowing the nature of the whole?” Phaedrus replies: “If Hippocrates the Asclepiad is to be trusted, one cannot know the nature of the body, either, except by this method.” Plato could not be expected to admire this idea, and especially not the implicit empirical methodology for science. Medicine teaches the invaluable lesson that natural knowledge begins with the investigation of facts concretely ex­perienced. It was this idea that Democritus and later Epicurus introduce into the philosophy of nature. Plato knew this alternative, and knew he was rejecting it.²⁶