The fact is that he whose purpose is to know anything better than the multitude do must far surpass all others both in his nature and in his early training. And when he reaches early adolescence he must become possessed with an ardent love for truth, like one inspired; neither day nor night may he cease to urge and strain himself in order to learn thoroughly all that has been said by the most illustrious of the Ancients. And when he has learnt this, then for a prolonged period he must test and prove it, observing what part of it is in agreement, and what in disagreement with obvious fact. Thus he will choose this and turn away from that.

Peri Physikon Dynameon III, 10 GALEN

Pergamon rose rapidly in the Hellenistic world after Attalos I Soter defeated the encroaching Galatians in 235 B.C. Although his alliance with Rome led to Pergamon's absorption into the empire in 133 B.C., it freed Attalos and his successors to make their city the wonder of Asia Minor. Its hillside location, rivers and fertile valleys invited inspired architecture and supported a wide range of agriculture. Eumenes II, the son and successor of Attalos, established a library designed to rival that of Alexandria. Although it never achieved that rank, it came close enough to alarm the Ptolemies, who banned the export of papyrus to hinder the Pergamene library's growth. In response, Pergamene artisans developed charta pergamena, specially treated animal skins which evolved into the parchment of later centuries. When scholars fled the political turmoil that periodically erupted in Alexandria, they most often came to Pergamon. A great Asclepieion or temple of healing arose across the river from the main city, and as a hospital and sacred site it developed into the chief centre for Asclepios (son of Apollo and father of Hygieia, goddess of health), just as Delphi was especially sacred to Apollo, Eleusis to Demeter and Ephesos to Artemis. Pergamon became a city where economic prosperity, classical learning and the healing arts intermingled, as if it were destined to provide a birthplace and home for Galen, the greatest physician of the ancient world.

Galen was born in A.D. 130 on a flourishing country estate between Pergamon and the sea. His father, Nikon, was an architect, mathematician and knowledgeable practitioner of animal husbandry, and his mother was irascible and querulous, a temperament sharpened by contrast with her husband's kindly nature. Galenos, 'serene', was chosen as the child's name, perhaps to give direction to his character, although it failed to indicate his capacity for intense concentration and his impatience with dogmatic viewpoints. As Galen grew up, he learnt mathematics, astronomy, agriculture and animal husbandry from his father, but he often visited the city and grew accustomed to its ways. He watched a new and enlarged Asclepieion rise on the ancient site of the temple of healing and marvelled at its splendour. A covered walk, three thousand feet long, connected the city and its monumental entry. Within its enormous colonnaded walls stood a temple modelled after the Pantheon, a great circular nursery, a theatre, a temple dedicated to Hadrian, an altar for Artemis and Hygieia Eileithyia (goddess of childbirth), and a sacred spring with its temple. An underground passage connected the nursery with the centre of the square, perhaps for religious functions surrounding childbirth. By the time Galen was ready to begin formal studies in the city at the age of fourteen, the sacred structures were complete.

Nikon desired a public career for his son. Besides teaching him a great deal about Nature and quickening his interest in science, Nikon sought to imbue Galen with broadmindedness and appreciation for differing standpoints. Galen attended lectures given by exponents of the four accepted schools of thought: those of Plato, Aristotle, the Stoics and Epicurus. Whilst he listened well to each view, his early mathematical training made him wonder about the uncertainties implicit in conflicting arguments and explanations. He might have become a mathematician, but a dream inspired by Asclepios urged him to study medicine as a means of discovering truth and using his diverse talents in an integrated way. He undertook anatomical studies under the anatomist Satyros from Smyrna, a man of such fame that he was the permanent guest of Rufinus, the architect who had restored and enlarged the Asclepieion. Four years later Nikon died, and Galen felt free to continue his studies elsewhere.

He travelled to Smyrna to study under Pelops and then to Corinth to work with Numisianos. While he was in Smyrna, he found time to continue his philosophical training under Albinus the Platonist. By the time he reached Alexandria in A.D. 152, he was already a writer whose books on anatomy were respected. Besides continuing his studies of anatomy in Alexandria with Heracleianos, he roamed Egypt in search of herbs and medicines, visited renowned lecturers and engaged in medical and philosophical debates. In 158 he returned to Pergamon, where he was received with honour and appointed physician to the schola gladiatorum. In assuming the task of treating gladiators, whose wounds were diverse and nasty, he gained the opportunity to compare human anatomy with that of the animals he had studied. His success was shown by the fact that he was reappointed to the post four times; he might have continued in that office indefinitely had not war between Pergamon and the Galatians stopped the gladiatorial contests. In the absence of demanding work, Galen decided to visit Rome.

Galen arrived in Rome in 162, just when Antoninus Pius was succeeded by Marcus Aurelius. He wrote, was active in medical circles and attended the lectures of Eudemos the Aristotelian. Highly respected in a city of intellectual and scientific luminaries, he was called to attend to Eudemos when he fell ill. Soon the leading medical theorists were engaged in hot debate over the cause and cure of the affliction. Galen had his way and Eudemos was cured, but he had incurred such animosity that Eudemos warned him of the possibility of assassination. Galen thought it best to return to Pergamon, where he could write and practise in peace, but his reputation in Rome soared in his absence, and soon Marcus Aurelius called him back to be royal physician to his son, Commodus, in the emperor's absence in the wars on the Germanic borders.

As court physician, a post he retained upon the succession of Commodus in 180, Galen found leisure to reflect upon what he had learnt and to write a number of treatises on medical and philosophical subjects. When a great fire destroyed the Temple of Peace on the Sacred Way in 192, a number of Galen's books were lost. Perhaps this tragedy was a signal to Galen to withdraw from public life, for he retired to Pergamon, where he lived and wrote in peace and honour, avoiding the confusion and erratic events of the end of the century. Little is known of his last years, except that he died in 199, assured of a place in philosophical and medical history. He could not have known that his views would provide the foundation for Islamic medicine for more than a millennium, or that the revival of interest in classical learning would secure his authority in medicine throughout Europe until Paracelsus gave a new impulse to medical studies.

Galen was a prolific and sometimes prolix writer. One hundred and eighteen works survive out of the seven hundred that he authored. By the end of his life, he could not remember all his own treatises. He felt the need to establish a bibliography of his works and composed two essays which ordered them and commented on his lifelong growth as a thinker and physician. In doing so he produced the first autobiography of a scientist and the first bibliography in recorded history. In addition, he almost casually revealed the critical ingredients of his insights and subsequent influence. First of all, he continued his philosophical training throughout his life. He emphasized logic and mathematics in his studies, but he demonstrated a remarkable capacity to blend open-mindedness towards differing viewpoints with a willingness to draw firm conclusions. Secondly, he had a deep veneration for ancient teachers and contemplated their insights reverently. Though he repeatedly called Hippocrates "divine", he shunned dogmatic affirmation of hoary views and slavish adherence to received traditions. Thirdly, he believed that empirical observation is essential to the study of human health, and for him anatomy provided the key. Unless one knows how an organ functions, he taught, one can neither recognize its healthy condition nor alleviate its afflictions, and the function of an organ can be understood only within the context of the unity of the whole organism and its unity with the environment. Galen was an early pioneer of holistic medicine.

Just as Galen had learnt from the four accepted philosophical systems of his day, he also examined the chief schools of medicine. And just as he borrowed elements from each philosophical school, so he extracted the essence of diverse medical views while rejecting the considerable dross associated with them. Of ancient schools, the Hippocratic was the oldest. Whilst all physicians paid homage to the Greek founder of medical science, some held that all medical wisdom could be discerned in the Hippocratic system. The Dogmatic school tried to reconcile Hippocratic teachings with those of Aristotle but refused to accept the possibility of medical insights outside this pair. The Empirical school grew out of the anatomical studies which flourished in Alexandria and based its teachings on vigilance (teresis), clinical histories and analogy. Unfortunately, its obsession with details tended towards a pharmaceutical experimentation which verged on the bizarre. Three contemporary schools of thought emerged with the Roman conquest of the Greek world. The Methodist school, based on the atomism of Epicurus, reduced all disease and dysfunction to constriction and laxity of pores in the body, thereby elevating one type of clinical observation to the level of operating principles. The Pneumatic school asserted that all disorders were due to disproportion in the airs and gases circulating in the body, but there was no recognition that some gases are the result of activity in organs. The Episynthetic school tried valiantly to reconcile these views, and though its proponents had excellent medical training, they lacked the philosophical grounding necessary to elaborate a sound scientific method.

Galen sought to base the art of medicine on a durable scientific method supported by an adequate philosophical foundation, and he attempted to incorporate the best insights of all the schools. "To what sect does Galen belong?" the anatomist Martialis once asked, and he was answered that Galen belonged to none and called slaves those who accepted any teaching as final and complete. Yet Galen never felt that he had discovered irrefutable solutions. Even though he rejected the pretensions of the schools with vehement polemic, his recurrent suspicion that medicine could be recast in mathematical form and that anatomy could be rooted in geometry pointed to a system which ever eluded him. Nonetheless, he developed a number of views which gave direction and coherence to medical studies.

"Hippocrates", Galen wrote, "was the first known to us of all who have been both physicians and philosophers, in that he was the first to recognize what Nature does." Galen took as his own point of departure the teaching of Hippocrates that the individual organism is a unity which reflects the unity of Nature (Physis), of which it is a part. Both health and disease – any specifiable condition in the organism – must be understood by reference to that unity, especially if one seeks to blend diagnosis, prognosis and therapy. Physiology – from physis and logos – is therefore the study of reason and causality in Nature. For Galen, physiology includes a large share of physics and chemistry, themselves considered to be the study of the intelligent (and therefore intelligible) processes of Nature. Rather than succumb to the Roman tendency to reduce biology to physics, Galen was inclined to assimilate physics to biology. He willingly accepted and freely adapted the scientific methodology of Aristotle and his disciple, Theophrastus, but he took his philosophy from Plato, whose ethics and doctrine of the soul were essential to Galen's thinking.

The chief characteristic of Nature, according to Galen, is techne, its creative artistry. In living organisms – though all of Nature is alive at least in some insensate degree – techne is exhibited in growth and nutrition, which depend upon natural faculties that draw appropriate material to themselves. Through assimilation, the organism alters the attracted material into itself. Although organisms are subject to phora or passive motion, which is depicted by mechanical laws, they function by self-movement. Drastike kinesis, active motion, or alloiosis, alteration, cannot be encompassed in mechanical laws, because self-movement is a kind of self-determination depending upon the nature of the organism or organ. This motion can be understood in three ways, as dynamis (potentiality), energeia (actualization) and ergon (the result of energeia) – that is, in terms of work to be done, work being done and work completed. Whilst the categories of self-movement can be understood a priori, clinical observation based on detailed anatomical knowledge is critical for the diagnosis of any disease or imbalance in an organic system. If medical science is to progress, however, the details of specific cases have to be amenable to generalization. Galen preferred the power of deduction to the uncertainties of the inductive method, so he attempted to draw general conclusions from observation in order to deduce a practical theory of disease. He found Euclidean methodology compelling, but he knew that neither anatomy nor medicine could apply it inflexibly, even though analogies could be useful.

For Galen, logic and observation could not by themselves furnish the requirements of medical science. In insisting upon the importance of experiment, he became the first experimental physiologist, concentrating on a study of kidney functions and the physiology of the spinal cord. His studies led him to accept two views, which he sought intermittently to reconcile. In the first place, taking organic dysfunction and disease as phenomena which were not radically different in nature but only different points on the spectrum of illness, he tentatively accepted the Hippocratic theory of humours. In this view, diseases are caused by excess of one or more of the four humours – blood, phlegm, black bile and yellow bile. Excess is not determined by the amount of each humour present in the organism, but by its relation to the other humours. Each organic system has its own balance – a reflection of unity in multiplicity – and if one or another humour should increase significantly, systemic balance is upset and illness or disorder results. Though the humoral theory is not part of contemporary Western medical science, the theory of hormones is its offspring, and humours remain essential to Tibetan medicine even today. The attempt to restore balance in the four humours led Galen to seek out curative substances throughout Asia Minor, Egypt, the Greek islands, Palestine, Cyprus and Italy. His pharmacopoeia was so extensive that he had to transport much of it himself, since he could not rely on local druggists to have his exotic ingredients in stock.

The second view he found attractive was the pneumatic theory. Pneuma, literally 'breath', had two distinct but related meanings for Galen. As inspired air, it was drawn into the heart and carried through the arteries to all the tissues of the body. Although Galen did not discover the circulation of the blood, he recognized the heart as a pump. Circulating air purified and restored tissues as well as gave innate heat to the organism. As a subtle vital principle, pneuma works in three ways. Pneuma physikon (natural spirit) travels through the veins and governs the vegetative functions of the organism; pneuma zotikon (vital spirit) gives individual autonomy to the system as a coherent self-moving whole; and pneuma psychikon (psychic spirit) is the physiologically operative principle of soul, transmitted through the nerves. The imbalances which can occur in the humours have secondary effects, including inhibition in the flow of pneuma in the system. If the flow of pneuma is impeded, however, it may affect the humours. Thus the diagnosis and prognosis based on physiology must include psychiatry as well as a study of the organism's history and environment.

Galen accepted Plato's tripartite division of the soul – while affirming with Plato that the soul is a unity – and restricted medicine to the lowest aspect. Nonetheless, he believed that physicians had to have greater knowledge than the logician or philosopher precisely because the Asclepian art has to combine Apollonian theory with the practical reason of Artemis, goddess of the chase, who always finds her quarry. The true healer must master the three branches of philosophy: logic, the science of correct thinking and conceptualization; physics, the science of visible and invisible Nature; and ethics, the science of what to do. The physician must bring the highest ethical integrity to his assiduous studies of the ancients, careful experimentation and acute observation. Nature is alive and intelligent; the moral character of the physician reflects his recognition of the working of Nature herself. For Galen, the healer is successful not only because of his knowledge but also because he consciously seeks to assist Nature, who reveals her secrets to her faithful and devoted servants.

Although Galen accepted Plato's doctrine of the soul and admitted its potential omniscience, he concluded from his extensive study of animals and children that Nature sets limits at birth on possible growth and attainment. Education could not assure even willing students that they would become exceptional human beings with strenuous effort. It could, however, help one draw out the full range of possibilities which exist within the parameters of Nature, and he felt that few do this much. Some individuals are by nature good, and a few others evil, and education cannot significantly alter their natural constitutions. It can, nonetheless, support the naturally good and impose some restraint on the inherently evil. The vast majority, however, live between these extremes, and education can be of enormous help to them. For most human beings, Galen felt, ethical and intellectual progress is possible. In his treatise "On the Best Teaching", he debunked the method of the sceptic Favorinus, who taught his students to argue with equal facility on each side of a point. This approach involved the denial that there are starting-points for knowledge, and students were left to make their own unaided judgements. If the teacher cannot see with greater intellectual clarity than his students, Galen argued, he should not be in that profession.

Character could be influenced by education, Galen held, because those traits ascribed to personality and character are part not of the rational, but of the irrational soul – the spirited and vegetative aspects of psyche. Thus, children who do not yet possess a developed capacity for reasoning nonetheless display highly idiosyncratic personalities. Adults have to assume responsibility for their characters, since they can be altered and affected by education and training. Favorinus became a symbol for Galen of the dangerously bad teacher because he abnegated this quintessential function of education. To educate a person in a way which almost assures that he could not use his education to improve himself is to deprive him of the one means for moral and intellectual growth. Galen believed that challenging study and severe questioning could be harmonized readily with an unshakeable commitment to fundamental values. Although he refrained from attributing any sweeping teleological scheme to Nature as a whole, he was convinced that each organism, and a fortiori the human being, could be understood functionally only in terms of purposive processes and behaviour.

Galen's concern to fuse reason, observation and experimentation into a powerful method of demonstration compelled him to turn his attention to logic. He understood the power of the Aristotelian syllogism, though he preferred the method of linear proof found in Euclid. Early Arabic writers, who had access to some of Galen's writings now lost to history, were unanimous in their affirmation that Galen invented the fourth figure in traditional syllogistic logic, and Renaissance thinkers who did not know why often referred to it as the "Galenic figure". Though Galen explored the possibilities of the syllogism, he focussed his attention on logical fallacies, and in his Peri ton para ten Lexin Sophismaton (On Linguistic Fallacies), he argued that fallacious thinking arises both from flaws in argumentation due to grammatical ambiguities and from ambiguities in concepts. He was the first, and almost the only, thinker who had tried to classify every linguistic ambiguity on the basis of theoretical principles. Galen thought that language essentially signifies, and ambiguity is the degree to which signification is unclear. For Galen, recognition of this linguistic problem is essential, for he frequently found himself contending with physicians who confused labelling with diagnosis. They sought to find the proper label to fit the disease under study, and then would treat the label and not the patient. This tempting and delusive approach to healing constituted a flat denial of the unity of the organism. Its unconscious adherents tended to attack disease as if it could be separated out from the whole life of the sufferer – a view Galen laboured all his life to banish from medical practice.

Galen was honoured by physicians and philosophers, but the range of his genius was too great to be encompassed by many, even amongst his admirers. His philosophical and theoretical writings were often overlooked, and his medical theories were elevated to a level of certitude he never intended. His polemical demolition of alternative views made his own theories, when removed from the context of his judicious explanations, take on an air of authority which ignored their experimental basis. Galen, who vowed never to join a medical sect, became the posthumous founder of the dogmatic sect which triumphed over all others in both the Christian and the Islamic worlds. When, centuries later, Paracelsus burnt the books of Galen in a public lecture on medicine, the medical faculty who had hired him was horrified and saw to it that he would expound his theories elsewhere. Ironically, however, Galen would have applauded the act, for even when success and renown rewarded his labours, he believed that the moral and intellectual integrity of the true philosopher-physician harmonized veneration for those who had laboured before with uncompromising examination of every theory and standpoint. Galen is an exemplary representative not of those who claim ultimate truth, but of those who point the way to it.


The elements, the conscious life, the mind,
The unseen vital force, the nine strange gates
Of the body, and the five domains of sense;
Desire, dislike, pleasure and pain, and thought
Deep-woven, and persistency of being:
These all are wrought on Matter by the Soul!