Temperament

Summary

Temperament (Greek krasis, Arabic mizaj, Latin complexio or temperamentum) is the doctrine that every body possesses a characteristic qualitative mixture of heat, cold, moisture, and dryness, and that health depends on maintaining this mixture within its proper range while disease follows whenever one quality predominates beyond tolerable limits. The concept organized humoral medicine from its pre-Hippocratic roots through Galen’s systematic elaboration, its transmission into Islamic medicine via the translation movement, its installation at the centre of medieval university curricula, and its survival in Unani practice into the present day. For more than two thousand years it provided the foundational vocabulary for explaining why individuals differ, why some people are vulnerable to certain illnesses, and what a physician must know before prescribing anything at all.

Proto-Humoral Origins: Alcmaeon and the Four-Element Framework

The earliest theoretical account of disease as qualitative imbalance belongs to Alcmaeon of Croton, a philosopher-physician of the late sixth or early fifth century BCE. His formulation could hardly be cleaner: health is the isonomia (equal governance) of the body’s powers, while disease is their monarchia, the tyranny of one quality over the others.(Galen / Ian Johnston (trans.), 2006) This political metaphor for bodily order would prove remarkably durable; the same contrast between balanced mixture and pathological dominance runs without interruption from Alcmaeon to Avicenna.

The intellectual scaffolding on which temperament theory would eventually rest was supplied by Empedocles. His claim that all matter consists of four elements (earth, air, fire, and water), each bearing a characteristic quality pair, offered sufficient explanatory power that disease theories built on only three humours began to lose ground.(Nutton, 2023) Yet the canonical four-humour scheme appeared relatively late. The Hippocratic text The Nature of Man, which identifies blood, phlegm, yellow bile, and black bile as the body’s governing juices, was a minority position even within the Corpus it is now thought to belong to, and was attributed by Aristotle to Polybus, not Hippocrates.(Nutton, 2023) Black bile itself was a conceptual newcomer at the end of the fifth century, more a speculative hypostasis to complete a cosmological quartet than a clinical observation; the author of The Nature of Man still felt obliged to describe it as “the so-called black bile,” a formulation implying the term was far from universally familiar.(Nutton, 2023) In clinical practice, most Hippocratic authors worked with the more visible pairing of phlegm and bile rather than with all four humours.(Nutton, 2023)

The four-element, four-quality framework was never without critics. The author of Ancient Medicine dismissed it as the simplistic importation of philosophy into medicine, arguing that the many subtle qualities of particular foods (bitter, salt, acid) were the true agents of health and disease, not abstract elemental qualities.(French, 2003) This empiricist resistance would recur throughout the history of the tradition.

Galen’s Systematic Architecture

The theoretical synthesis that converted these diverse proto-humoral ideas into a rigorous doctrine of temperament was the work of Galen of Pergamon (129–c.216 CE). Galen adopted Aristotle’s four elements composed from the four primary qualities and linked them to the four humours: blood (hot and moist), phlegm (cold and moist), yellow bile (hot and dry), black bile (cold and dry).(Temkin, 1973) Digestion at the liver generates these humours from food. The body’s tissues owe their composition to them, and the characteristic krasis of each tissue, organ, and person is constituted by the balance that results.

Galen was precise about the number of possible temperaments. He insisted on exactly nine: one ideal mixture in which all four qualities were equally balanced, four simple mixtures in which one quality predominated (hot, cold, dry, or moist), and four compound mixtures in which a pair of qualities predominated together (hot and moist, hot and dry, cold and dry, cold and moist).(Temkin, 1973) Nutton emphasizes that the eight non-ideal temperaments indicated a predisposition to certain types of illness rather than being in themselves pathological — a point that distinguished Galen’s system from a simple disease taxonomy (Nutton, 2023). The balanced temperament was not only physiologically optimal but provided the diagnostic reference point from which all others were measured. Galen proposed that the skin of the palm of a well-balanced person’s hand furnished the best empirical standard for calibrating deviations from that ideal.(Temkin, 1973)

The technical vocabulary of the doctrine was equally precise. Eukrasia (good mixture) was Galen’s term for health at the level of constitution; dyscrasia (bad mixture) was pathology. Ian Johnston, in his edition of Galen’s disease treatises, notes that these terms are fundamental to Galen’s definitions of health and disease, and deliberately preserves them as transliterations rather than rendering them as “good/bad temperament,” since “temperament” in English carries psychological connotations absent from the Greek.(Galen / Ian Johnston (trans.), 2006) Within the category of dyscrasia, Galen distinguished ten varieties for the homoiomeric (uniform tissue) structures: four mono-dyscrasias (excess of one quality), four regular combined dyscrasias, and two irregular combined dyscrasias in which normally opposed qualities simultaneously dominate.(Galen / Ian Johnston (trans.), 2006) Galen’s formal definition of illness (“a state of the body, contrary to its nature, because of which the vital functions immediately suffer”) required dysfunction, not merely qualitative deviation, before a condition counted as disease rather than mere constitutional tendency.(Galen / Ian Johnston (trans.), 2006)

The foundational physiology also included the concept of innate heat (thermom emphyton), which Galen conceived not as an effect of motion or friction but as a primary, self-moving vital substance identical with life itself.(Galen / Ian Johnston (trans.), 2006) Innate heat governed digestion, the conversion of nutrients into blood and humours, and the maintenance of each body’s characteristic thermal register: it was the physiological engine driving the temperament system.

What made temperament clinically indispensable was its connection to therapy. Galen’s concept of “therapeutic indications” (endeíxeis) grounded every prescribing decision in four principles, of which two bore directly on temperament: the patient’s individual constitution and the nature of the affected organ.(García-Ballester, Luis, 2002) One could not prescribe correctly without knowing the patient’s baseline krasis, because the same treatment that corrects cold dyscrasia in one body might overheat another. Galen summarized this moral-medical demand in De sanitate tuenda: to fail to reach old age without illness through intemperance or ignorance was the patient’s own fault, and medicine understood as diaita (the whole regulation of daily life) was the means of prevention.(García-Ballester, Luis, 2002) The six non-naturals (air, food and drink, motion and rest, sleep and wakefulness, retention and evacuation, and the passions of the soul) represented the specific domains in which temperament-appropriate regulation was required.(Temkin, 1973)

García Ballester’s formulation is precise: “The ‘temperaments’, which make up the organic structures of each organ, of each body and of each individual, consist precisely of this mixture (mixture of qualities, mixture of humours) or krâsis. The balance or imbalance of this mixture (krâsis) was to mark the separation between what was normal and what was pathological.”(García-Ballester, Luis, 2002)

Galen also extended temperament into pharmacology. Drugs were classified by their primary qualities at four degrees of intensity (first-degree cooling, second-degree heating, and so on) so that the physician could match medicinal quality to constitutional deficit.(Temkin, 1973) This qualitative pharmacy proved one of the most durable elements of the entire system, outlasting the demise of Galenic anatomy and physiology.

The Psychophysical Dimension: Soul Follows Body

One of the most consequential corollaries of temperament doctrine, and one of its most theologically contentious, was Galen’s claim that the capacities of the soul invariably follow the mixtures (temperamenta) of the body. In Galen’s own words, preserved in Johnston’s translation: “I have found the proposition to be true and invariable that the capacities of the soul follow the mixtures of the body, and not once or twice but very often.”(Galen / Ian Johnston (trans.), 2006) The soul has three parts (concupiscent, passionate, and rational), each with a physiological centre in the body;(Temkin, 1973) and Diocles had already proposed, earlier, that pneuma obstruction at the heart could produce melancholy by disrupting psychic pneuma.(Nutton, 2023) More broadly, Nutton notes that Diocles’ theory of health and disease was marked by an increased methodological sophistication: he ascribed the internal causes of disease to excess or deficiency within the body’s four elements and four primary qualities — the same causal logic that Galen would systematize (Nutton, 2023).

The consequence for clinical practice was that mental diseases were explicable by the same physical-causal framework as bodily ones. Galen himself maintained a careful public agnosticism on the metaphysical substance of the soul. He insisted it was “irrelevant to the doctor in treating diseases whether the soul is mortal or immortal,“(Galen / Ian Johnston (trans.), 2006) but his De moribus went further, arguing that moral character was physically grounded in bodily mixture. Owsei Temkin summarizes the doctrine’s religious difficulty: a churchman like Nemesius could not accept Galen’s teaching on the soul in its entirety, and Jewish, Christian, and Muslim theologians alike were troubled by the implication that a soul conditioned by bodily mixture was unlikely to be immortal.(Temkin, 1973)

Despite this theological friction, the psychophysical dimension of temperament became integral to the tradition. Friedrich Hoffmann in the early eighteenth century could still write (now in a corpuscular-mechanical idiom) “Hence, as Galen said, the habits of the mind follow the temperament of the body,” demonstrating that the claim survived the dissolution of its original physiological framework by being reclothed in the language of mechanics.(Temkin, 1973)

Temperament also established individuality as a clinical value. Diocles, in the fourth century BCE, had already emphasised that health was the restoration of the individual’s natural balance, and that this balance shifted with the seasons, the weather, and the process of ageing.(Nutton, 2023) Galen codified this individuality into his system of constitutions and his insistence that every prescribing decision required knowledge of the particular patient’s mixture. Women, in this framework, were not a separate biological category but occupied a position on the continuous spectrum of constitutional quality, sharing cold, moist temperament with children and eunuchs, and requiring gentler treatment for that constitutional reason rather than for any sex-specific logic.(Nutton, 2023) Galen defined the latitude of health broadly: one remained within it as long as one could “take part in government, bathe, drink and eat, and do the other things we want.”(Temkin, 1973)

Islamic Transmission: Mizaj and the Unani Inheritance

The transmission of temperament doctrine into Arabic medicine was thorough and preserving. The translation movement of the eighth through tenth centuries (centred on Hunayn ibn Ishaq and his school) brought Galen’s core texts on temperaments, humours, and health into Arabic with careful philological attention. By 650 CE, as Nutton observes, learned medicine had consolidated into Galenism: a humoral system easily harmonised with Aristotelianism, Platonism, and monotheism, dominating the Greek East and subsequently the Muslim world.(Nutton, 2023) The doctrine of the six non-naturals, which organized Galenist therapeutic advice around the regulation of daily life, was itself a product of this textual consolidation: not a single Galenic passage but a conflation of several, produced by later Galenists.(Nutton, 2023)

In Arabic, krasis became mizaj, and the concept remained the keystone of the system. Ullmann summarizes the Arabic formal account: there are nine possible temperaments — one balanced and eight unbalanced (four simple, four compound) — each further modified by climate, age, sex, and habit.(Ullmann, 1978) Islamic medicine also preserved the Galenic four-humour framework intact: Pormann and Savage-Smith describe how the “single most pervasive explanatory medical principle” in medieval Islamic medicine was humoral pathology inherited from the Greeks, with each humour associated with two primary qualities, one of the four seasons, and one of the four temperaments.(Pormann, 2007) Ibn Ridwan’s eleventh-century treatise on Egyptian health illustrates how fully the framework had been internalized: he argues that Egypt’s ecology is “ecologically balanced within its own sphere under normal circumstances,” with Egyptians’ bodily constitutions adapted to their environmental temperament, following the same logic by which any individual’s constitution is formed by and adapted to its characteristic conditions.(Dols, Michael W. (trans.), 1984)

Avicenna’s philosophical elaboration added a further argument for the necessity of temperament: each body requires a unique soul suited to its particular mixture. Avicenna’s rejection of transmigration rested precisely on this one-to-one correspondence: every body’s temperament necessitates a specific soul from the emanated order, making it impossible for a single soul to migrate into multiple bodies each of which already requires and has its own.(Gutas, 2016) Temperament was thus not merely a diagnostic classification but a metaphysical anchor for individual identity.

The Islamic medical profession, as Michael Dols observes in his study of Ibn Ridwan, defined itself in terms of adherence to Galenic medicine rather than institutional licensing. The non-naturals and the temperaments together counted as Galenism’s most enduring contributions to medical thought, forming the practical and theoretical core of what an educated tabib (physician) was expected to know.(Dols, Michael W. (trans.), 1984)

Medieval Latin Reception: Complexion and the University Curriculum

The Latin West received temperament doctrine through a double channel: Constantinus Africanus’s eleventh-century translations at Montecassino, and the surge of new Galenic translations in the late thirteenth century. The key technical term was complexio (Latin for krasis) and the doctrine of complexional medicine organized not only diagnosis and therapeutics but the entire rational structure of university medical education.

Roger French notes that the “New Galen” texts on complexion, crisis, and simples arrived in the universities in the 1270s and 1280s, dramatically widening the theoretical apparatus available to scholastic physicians; when Arnau of Vilanova advised Pope Clement V on a new curriculum for Montpellier in 1309, he centred it on precisely these complexion texts.(French, 2003) The late antique Alexandrian commentary tradition had also transmitted a founding formula: John of Alexandria’s statement that “medicine and philosophy are sisters” (philosophia et medicina duae sorores sunt) made complexional theory not merely a clinical tool but a mark of the learned rational doctor.(French, 2003)

The therapeutic axiom that undergirded the whole system was “opposites cure opposites,” elevated to the status of “the law of Hippocrates” and treated as an axiomatic common conception requiring no proof.(French, 2003) Galen had effectively invented this Hippocratic pedigree: his commentaries reconstructed Hippocrates as a Rationalist who had originated the four-element theory, thereby securing ancient authority for the complexional framework Galen himself had systematized.(French, 2003)

Medieval practice also adopted Galen’s extension of temperament theory to the life course. Youth was assigned a hot and moist temperament; adulthood hot and dry; maturity cold and dry; old age cold and dry in the principal organs, with accumulated cold and moist waste.(Chishti, 1988) This life-stage taxonomy organized both prophylactic and therapeutic advice, since the physician had to know not merely the individual’s constitutional type but where on the ageing spectrum that constitution currently stood.

The pseudo-Aristotelian Problems, which circulated widely from the Hellenistic period, shows temperament thinking permeating educated discourse well beyond professional medicine: the text’s questions about why wine affects behaviour, why the intellectually gifted are often melancholic, and why seasonal changes produce characteristic illnesses all presuppose the humoral-qualitative framework.(Nutton, 2023)

The Unani Continuation: Nine Temperaments and Sixteen Intemperaments

While Galenism declined in Latin Europe, Unani medicine (“Greek medicine in its Arabic modification,” as Temkin phrases it) continued to be taught and practiced in Islamic countries, sustaining the temperament system as a living clinical reality rather than a historical curiosity.(Temkin, 1973)

The Unani system preserves the nine temperaments with formal precision: one equable (balanced) temperament, four simple intemperaments (hot, cold, dry, moist), and four compound intemperaments, yielding a total of nine qualitative types identical to the structure Galen specified.(Chishti, 1988) The diagnostic system further distinguishes sixteen intemperaments: each of the eight nonequable temperaments can manifest as either qualitative (a change in quality alone) or material (involving excess or deficiency of humour), doubling the basic eight into sixteen modes of deviation from balance.(Chishti, 1988)

The humours themselves arise from digestion at the liver in a staged process: blood from the finest nutrients, phlegm from second-stage digestion products, yellow bile from third-stage, and black bile from the least digestible fractions.(Chishti, 1988) Avicenna, in the Unani inheritance, refined humoral theory further by distinguishing primary humours from secondary ones (the intracellular and extracellular tissue fluids) and identified abnormal black bile as a toxin capable of causing cancerous growth.(Chishti, 1988)

Constitutional assessment in Unani practice attends to multiple diagnostic registers: skin complexion reveals humoral dominance (rose between white and red indicating balance; yellow pointing to yellow bile; black to black bile; red to blood; white to phlegm)(Chishti, 1988); the breath pattern indexes emotional states: anger is sudden forced exhalation, fear sudden forced inhalation, joy gentle exhalation, gloom gentle inhalation.(Chishti, 1988) The three states of the body (health, disease, and a neutral intermediate state) organize clinical judgment, with the neutral state subdivided into three forms: partial co-existence of health and disease in different parts, incomplete realization of either state (as in the elderly or convalescent), or oscillation between states (as in persons whose hot temperament makes them well in winter and ill in summer).(Chishti, 1988)

The Unani view of mental disease follows the Galenic psychophysical logic: mental conditions are not the cause of physical ailments but the result of humoral imbalance, so phlegm excess accounts for mental sluggishness and is corrected by resolving the excess phlegm.(Chishti, 1988) The environment-constitution relationship governs both, as illustrated by the doctrine that persons whose ancestry is in hot climates cannot adjust quickly to cold environments; the vital force cannot generate sufficient heat, and sadness, depression, and melancholy result.(Chishti, 1988)

The system’s distinctive claim (articulated sharply by Hakim Chishti in his practitioner handbook) is that the Tibb tradition rejects germ theory as a sufficient explanation of disease. Microbial overgrowth, in this view, is not the primary cause of illness but its consequence: it is the prior imbalance of temperament that provides an altered biotic environment in which bacteria and viruses can flourish.(Chishti, 1988) Treatment therefore aims not at eliminating pathogens but at restoring the temperamental equilibrium from which pathogen susceptibility arose, using remedies classified by their own qualitative degrees.(Chishti, 1988)

Early Modern Persistence and Mechanistic Reinterpretation

The early modern period did not simply abandon the temperament system; it mechanized it. Friedrich Hoffmann’s early-eighteenth-century corpuscular medicine preserved the clinical categories while recasting their physiological basis: blood is “well-tempered” when its particles are mixed to produce even motion; sanguine temperament arises from blood particles in slight excess; choleric temperament from greater excess; and the dictum “the habits of the mind follow the temperament of the body” persisted without alteration.(Temkin, 1973) Temperament thus survived as a classificatory tool for human constitution and a somatic theory of behavior well into the nineteenth century, even as the physics underlying it had been replaced.

The deeper mechanism of the system’s demise is identified by Temkin as the “mechanization of qualities.” Sanctorius’s thermometer replaced subjective hot and cold with a measurable quantity; the Aristotelian primary qualities, which Galen had understood as objective features of matter, were demoted to secondary subjective sensations.(Temkin, 1973) This transformation was, as Temkin puts it, “as destructive to Galenic science as doing away with fire, air, water, and earth as chemical elements.”(Temkin, 1973) Harvey’s demonstration of the circulation of the blood (1628) overturned the physiological substrate on which the generation and distribution of humours depended;(Temkin, 1973) Vesalius’s anatomy had already demonstrated that Galen’s anatomical authority rested on animal, not human, dissection.(Temkin, 1973)

Even so, Galenic practice (bleeding, purging, dietetics, and galenicals) outlasted the fall of Galenic science, because practitioners had no reason to abandon treatments that had apparently worked for centuries.(Temkin, 1973) By 1870, however, positivistic medicine had absorbed what was needed of the old clinical wisdom and no longer required the theoretical framework of temperament. Galenism was, in Temkin’s phrase, “gently and quietly, but none the less resolutely… handed over to classicists, Arabists, and historians for disposal in the cemetery of the great dead.”(Temkin, 1973)

Scholarly Assessment

The scholarship on temperament is shaped by Owsei Temkin’s Galenism: Rise and Decline of a Medical Philosophy (1973), which remains the standard account of how the concept was systematized, transmitted, and eventually displaced. Temkin’s analysis of the “mechanization of qualities” as the deep cause of Galenism’s collapse is widely accepted. For the Greek foundations, Nutton’s Ancient Medicine (3rd ed., 2023) provides the most detailed textual treatment of pre-Galenic humoral diversity, and Johnston’s edition of Galen’s On Diseases and Symptoms (2006) clarifies the terminological precision of the doctrine. The Islamic transmission is well served by Garcia Ballester’s Galen and Galenism (2002) and by Dols’s study of Ibn Ridwan. The living Unani tradition is documented in Chishti’s Traditional Healer’s Handbook (1988), which presents the nine-temperament and sixteen-intemperament system as current clinical practice rather than historical reconstruction. The central scholarly tension concerns whether temperament doctrine should be understood as a coherent theoretical system or as a flexible clinical vocabulary that accommodated contradictory physiological commitments across two millennia.

Modern Primate Research: Reactive Temperament and Constitutional Variation

Contemporary neuroendocrinology has produced a body of evidence that maps onto the ancient doctrine of constitutional temperamental types with unexpected precision, while grounding it in measurable physiology. Robert Sapolsky’s long-term field and laboratory work with rhesus macaques identified a stable minority phenotype that closely parallels the concept of a constitutionally reactive or choleric temperament. Roughly 20 percent of rhesus monkeys are what Sapolsky calls “high-reactors”: individuals who perceive challenge where others perceive none, respond to novelty or social separation with fear, and mount large glucocorticoid surges that their more phlegmatic conspecifics do not.(Sapolsky, Robert M., 2004) The parallel to the humoral tradition’s account of an innately excitable, heat-dominated constitution is not incidental — the high-reactor phenotype represents genuine individual biological difference in stress-axis calibration.

What the primate data add to the ancient constitutional picture is a dual-origin model for such differences. Sapolsky found that infant monkeys had a significant chance of sharing the high-reactor trait with their biological fathers even when they were raised entirely without them — a finding consistent with a heritable, genetic contribution to reactive temperament.(Sapolsky, Robert M., 2004) Yet the same high-reactivity phenotype could be entirely prevented by fostering susceptible infants early in life to atypically nurturing mothers, demonstrating that the constitutional tendency, however biologically grounded, remains plastic under favorable early-environment conditions.(Sapolsky, Robert M., 2004) The ancient debate between nature and regimen — between an inborn krasis and its modifiability through diaita — thus reappears, empirically tractable, in twentieth-century primatology.

Temperament in Early Twentieth-Century Vitalist Medicine

The doctrine of constitutional type persisted in vitalist medicine well past Galenism’s academic collapse. Henry Lindlahr’s Nature Cure system identified the nervous and negative temperament as a specific constitutional type requiring modified therapeutic management. Writing in 1918, Lindlahr argued that such constitutions were predisposed to nervous exhaustion, and that prolonged fasting — a central Nature Cure therapy — was specifically contraindicated in them because the auto-intoxication accompanying a long fast fell heavily on already-taxed nervous systems, capable of triggering morbid psychic states including depression, abnormal visions, and in extreme cases hallucinations.(Lindlahr, Henry, 1918) This was not a metaphorical use of temperament language but a clinical contraindication grounded in a specific constitutionally-based physiology — an instance of the ancient regimen principle that the same treatment is not appropriate for all constitutional types.