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During the lifetime of René Descartes, Western medical science was in a period of profound transition. The first half of the 17th century saw the clash of ancient medical doctrines with new discoveries and philosophies emerging from the Scientific Revolution. Traditional Galenic medicine, based on the balance of the four humors, still dominated medical practice. At the same time, pioneering physicians and natural philosophers were laying the groundwork for modern medicine through anatomical studies, experimental methods, and new theoretical frameworks. Below is an extensive overview of the status of Western medical science in Descartes’s era, highlighting both enduring traditions and revolutionary changes.

The Dominance of Galenic Tradition and Humoral Theory

For centuries leading up to 1600, European medicine was grounded in the teachings of Galen and Hippocrates. Health was thought to depend on a harmonious balance of the four humors – blood, phlegm, yellow bile, and black bile – each associated with elemental qualities and organs. Disease, in this view, resulted from an excess or deficiency of a humor, and treatments aimed to “rebalance” the body’s humors. Physicians prescribed bloodletting, purging, emetics, and other so-called “heroic” therapies to shock the body back into equilibrium. Remedies were often guided by Galenic principles: for example, a “hot” illness might be treated with a “cold” herb, following the belief in opposites restoring balance. This holistic humorism was deeply ingrained in medical theory and practice well into the 17th century – Galenic medicine had persisted “from the time of the ancient Greeks to the start of the industrial era” as a working system.

Medical education around 1600 reinforced this classical outlook. Learned medicine in European universities still relied on ancient authorities’ texts, especially Galen’s writings and Arabic commentaries like Avicenna’s Canon. Aspiring physicians memorized Latin treatises on theorica (physiology and causes of disease) and practica (diagnosis and treatment of illnesses). Scholarly medicine valued theory, but by the late Renaissance there was increasing emphasis on practical knowledge of diseases (nosology) and bedside experience. Still, the university curriculum remained heavily traditional. The status of university physicians was high – they formed an elite, often licensed by guilds or colleges (for example, London’s Royal College of Physicians, established in 1518). By contrast, hands-on healers like barber-surgeons, apothecaries, and midwives occupied lower rungs in the medical hierarchy, despite the essential services they provided.

Outside academic circles, ordinary people often relied on folk medicine and household remedies. Herbal lore remained important; indeed, many learned physicians themselves used extensive herbals when prescribing drugs. Astrology and superstition also survived at the fringes of care: some practitioners timed treatments by the stars, and even high-ranking physicians might entertain notions like the “royal touch” – the belief that a king’s touch could cure scrofula (tubercular neck swellings). Overall, at the dawn of the 17th century, Western medicine was still rooted in its medieval past, and humoral theory provided the overarching framework for understanding health and disease.

Renaissance Anatomical Revolution and Its Impact

Despite the conservative backdrop, the Renaissance had already planted seeds of change in medicine, particularly through advances in anatomy. A landmark event occurred in 1543, a few decades before Descartes’s birth, when Andreas Vesalius published De humani corporis fabrica (“On the Fabric of the Human Body”). Vesalius’s masterful illustrated atlas, based on his own dissections of human cadavers, “operated a sort of revolution within the medical sphere”, breaking the long-held dominance of the Galenic anatomical model. By directly observing and dissecting human bodies, Vesalius and his contemporaries exposed many errors in Galen’s anatomy (which had been derived from animal dissection). This Vesalian revolution “interrupted the long and widely accepted hegemony of the Hippocratic-Galenic model” in anatomy. For example, Vesalius showed that the human sternum has three parts (not seven, as Galen claimed from ape anatomy), and he challenged the idea that invisible pores in the heart’s septum allowed blood to pass between ventricles. Such findings were significant cracks in the edifice of ancient authority.

By Descartes’s lifetime, Vesalius’s influence had permeated European medical education. Human dissection became a fixture of training for physicians in many universities, often conducted in newly built anatomical theaters (Padua’s famous anatomy theater opened in 1594). These dissections and judicial autopsies (post-mortems on the deceased) not only taught normal anatomy but also began to correlate clinical symptoms with internal pathology. Physicians could now observe “morphological changes of internal structures” corresponding to diseases observed in life. This early practice of pathological anatomy – linking lesions found on autopsy to illness – was a forerunner of modern pathology. It marked a shift from viewing disease purely as imbalance of humors to recognizing localized changes in organs.

Other Renaissance anatomists built on Vesalius’s work. Realdo Colombo (1516–1559) discovered the pulmonary circuit – showing that blood travels from the right side of the heart to the lungs and then to the left side – improving upon Galen’s incomplete understanding of blood flow. Hieronymus Fabricius (1537–1619), who taught at Padua, described the valves in veins in 1603, noting their one-way nature. These venous valves puzzled Fabricius but provided a crucial hint to his student William Harvey, who would soon reinterpret the circulatory system entirely. The late 16th and early 17th centuries also saw better understanding of skeletal and muscular systems, often aided by artists and anatomists working together (as Leonardo da Vinci had earlier, and later Govard Bidloo or others would do).

In the field of surgery, the Renaissance brought practical improvements. Ambroise Paré (1510–1590), a French military surgeon a generation before Descartes, had abandoned the harsh practice of cauterizing gunshot wounds with boiling oil. Instead, Paré applied soothing balms (like a turpentine, egg yolk and oil of roses mixture) and found that wounds healed better. He also reintroduced the use of ligatures (tying off blood vessels) during amputations to control bleeding, although in an era before antiseptics this could lead to infections. By 1600, Paré’s surgical writings and humane techniques were widely read, influencing surgeons of Descartes’s time to favor gentler wound care. These developments in anatomy and surgery set a precedent: direct observation and experience could correct and improve upon the wisdom of the ancients – a core idea that would blossom in the 17th century.

The Scientific Revolution and New Medical Philosophies

The intellectual upheavals of the 17th-century Scientific Revolution profoundly affected medical science during Descartes’s life. Thinkers like Francis Bacon (1561–1626) advocated for empirical methods – learning about nature through experiments and inductive reasoning rather than by venerating old authorities. This spirit spread into medicine. Indeed, “in the 17th century the natural sciences moved forward on a broad front,” and medicine was no exception. A growing number of physicians began to doubt doctrines that had been accepted for ages and sought new explanations grounded in chemistry or physics. As Bacon and Descartes discarded Aristotle’s four-element theory (earth, air, fire, water) in favor of new chemical understanding of matter, the old idea that health was governed by elemental balance started to lose its credibility. The door opened for new medical philosophies that challenged the humoral theory.

One such challenge came from Paracelsianism, stemming from the influence of Paracelsus (1493–1541). Paracelsus was a radical Swiss physician-alchemist who predated Descartes but cast a long shadow over the 17th century. He had dramatically rejected the humoral teachings – reportedly even burning the books of Galen and Avicenna in a bonfire – and introduced a new approach that viewed illness as caused by specific chemical imbalances or external poisons, not an imbalance of humors. Paracelsus pioneered the use of chemicals and minerals in therapy, such as mercury for syphilis and antimony compounds for other ailments. By Descartes’s time, Paracelsian ideas had evolved into the “iatrochemical” movement. Physicians in this school sought to explain bodily functions and diseases in terms of chemical reactions: for example, digestion as a fermentation process, or health as a balance of acids and alkalis rather than hot/cold humors.

Another new perspective was the mechanical philosophy championed by René Descartes himself and others. Descartes, better known as a philosopher and mathematician, had a keen interest in physiology and medicine. He believed the human body is essentially a complex machine, operating under mechanical laws. In his view, organs and muscles function like levers, pumps, and pulleys – concepts drawn from physics and mechanics. Descartes famously argued that animals are “automata” (living machines) devoid of souls, and that even in humans the body can be understood mechanistically, though he maintained the soul (mind) as a separate entity. This notion had wide repercussions in medical thought: it inspired a group of physicians known as iatrophysicists (or iatromechanists) who attempted to describe all physiological processes by physical principles. For example, they likened the heart to a pump and the lungs to bellows. Pioneers of this approach included Santorio Santorio in Italy and Giovanni Borelli, who applied Galileo’s physics to study the human body’s motions. Santorio (1561–1636) was especially innovative – he invented instruments to quantify bodily functions (such as a pulsilogarithm to measure pulse and a special scale to measure weight change after meals) and investigated metabolism by measuring “insensible perspiration” (continuous water loss through skin). In 1614 he published De Statica Medicina, detailing experiments where he weighed himself and his food to calculate how much matter the body secreted invisibly. This quantitative, measurement-based approach was revolutionary at the time, reflecting the new Cartesian zeal for measurement and mathematical analysis in science.

As a result of these influences, Western Europe’s medical community in Descartes’s lifetime became split between conservative Galenists and reformers embracing new philosophies. University faculties sometimes saw heated debates – the “Galenico-Paracelsian controversy” raged in places like Germany, France, and England during the early 1600s, as traditional professors resisted the introduction of chemical remedies and theories. Galenic teachings were “challenged successively by Paracelsianism and Helmontianism” (after Jan Baptist van Helmont). Jan Baptist van Helmont (1580–1644) was a Flemish iatrochemist who built on Paracelsus’s ideas while adding rigorous experiments; he even coined the word “gas” and studied digestion with quantitative methods. Van Helmont founded the iatrochemical school’s base in Brussels, although his writings still contained alchemical mysticism. Later in the century, the iatrochemical approach was refined by figures like Franciscus Sylvius (1614–1672) at Leiden, who explained diseases in terms of acid-base chemistry, and in England by Thomas Willis (1621–1675), an anatomist and physician who used chemical treatments and contributed to neurology. On the other hand, the iatromechanical school (physicalists) counted not just Santorio and Borelli but also many followers of Descartes in France and the Netherlands; these doctors tried to reduce physiology to geometry and physics.

Despite these divergent theoretical camps, they shared something important: a desire to replace older doctrines with a more “scientific” system. As one historian notes, there was “a general desire to discard the past and adopt new ideas” in 17th-century medicine. Many hoped to find a unifying, simple scientific theory that could guide all medical practice – whether based on mechanism or chemistry. Descartes himself believed that through understanding the laws of nature, medicine could become as certain as geometry. In his Discourse on Method (1637), Descartes famously wrote that improving medicine was one of his main goals, envisioning a future medicine that could “free us from an infinity of maladies, even perhaps the debility of old age”. He corresponded with physicians and engaged in dissections for over a decade, claiming “I doubt whether there is any doctor who has made such detailed observations as I” regarding anatomical studies. “I am now working to compose an abridgement of medicine, drawn partly from books and partly from my own reasoning,” he wrote to a colleague in 1638. Although Descartes never completed this grand synthesis (and withheld his Treatise of Man from publication after Galileo’s condemnation), his vision of a medicine grounded in indubitable scientific knowledge was emblematic of the era’s aspirations.

It is worth noting that while new theories proliferated, superstition and unscientific practices did not disappear overnight. A “substratum of superstition still remained” in medicine throughout the 1600s. For example, Richard Wiseman, an eminent surgeon to King Charles II, affirmed belief in the monarch’s healing touch for scrofula even in the late 17th century. Likewise, learned men like Sir Thomas Browne (physician and author) could still insist that witches were real. Alchemical quests for panaceas and elixirs continued, and many remedies had no rational basis. Nonetheless, the critical difference by mid-century was that empirical science had secured a foothold in medicine: increasingly, the best medical minds argued that knowledge must come from observation, dissection, and experiment rather than ancient dogma.

Breakthroughs in Anatomy and Physiology

Amid this rich intellectual ferment, some concrete scientific breakthroughs greatly advanced medical knowledge during Descartes’s lifetime. Foremost among them was William Harvey’s discovery of the circulation of blood, often cited as the single greatest 17th-century medical achievement. Harvey (1578–1657), an English physician, studied in Padua under Fabricius and absorbed the latest anatomical insights. Through a series of meticulous experiments and animal dissections, he came to understand that the heart works as a pump to move blood in a circuit around the body. In 1628 Harvey published Exercitatio Anatomica de Motu Cordis et Sanguinis in Animalibus (“An Anatomical Exercise on the Motion of the Heart and Blood in Animals”), which demonstrated that blood is pumped out from the heart through arteries and returns via veins in a closed loop. This overturned Galen’s 1400-year-old view that blood was continually synthesized in the liver and consumed by the organs. Harvey calculated the volume of blood the heart moved and showed it far exceeded what the body could produce anew; the only logical conclusion was that the same blood was circulating repeatedly.

The response to Harvey’s work was mixed but pivotal. His findings “aroused controversy” – conservative physicians, steeped in Galen, argued against him without even attempting his experiments. Many clung to Galen’s idea of blood ebbing and flowing like tides or being absorbed rather than recirculated. Yet Harvey’s evidence eventually carried the day, especially as younger physicians repeated his demonstrations. By the mid-17th century, the circulation of blood was becoming widely accepted as a fundamental truth – “a landmark of medical progress” that exemplified the power of experimental method. Equally important, Harvey’s approach showed a new way of doing science in medicine: he relied on precise observation and scrupulous reasoning, drawing conclusions from experience rather than deferentially quoting old authorities. This empirical methodology, paralleling Bacon’s philosophy, would become a cornerstone of modern medical science.

Harvey’s work also spurred further discoveries. One gap in his theory was the inability to see the fine connections between the arteries and veins. Harvey postulated the existence of tiny vessels – later named capillaries – to complete the circuit, but they were invisible with the naked eye. A few years after Descartes’s death, in 1661, Marcello Malpighi in Italy used one of the earliest microscopes to actually observe capillaries in a frog’s lung, thus vindicating Harvey’s prediction. Malpighi’s discovery showed how blood passed from arteries into veins via a network of microscopic vessels, and it also marked the birth of microscopic anatomy (histology). Although Malpighi was a young boy during Descartes’s lifetime (born 1628, the same year Harvey published De Motu Cordis), the development of the microscope had already begun. The compound microscope had likely been invented in the late 16th century in Holland, and Galileo himself improved one (he called it the “occhiolino”) by around 1624. Descartes, Galileo, and others were aware of the potential of lenses. However, it was only after mid-century that Anton van Leeuwenhoek and Robert Hooke truly revolutionized microscopy. Leeuwenhoek (1632–1723), a Dutch contemporary of Descartes (though much younger), would go on to report the first sightings of bacteria and protozoa in the 1670s, while Hooke’s Micrographia (1665) revealed the cellular structure of tissues like cork and plants. These developments were slightly after Descartes’s life, but their foundation was laid in the curiosity about the invisible world that arose in the 17th century. By 1650, the microscope was still a novelty, yet poised to open an entirely new frontier of medical science – one that Descartes did not live to see, but which was a direct extension of the experimental spirit of his age.

Beyond circulation, other anatomical and physiological advances occurred. Harvey’s second book on embryology, Exercitationes de Generatione Animalium (1651), broke ground in the study of reproduction and development. Although published just after Descartes’s death, Harvey had likely shared some insights earlier. He rejected prevailing ideas like spontaneous generation and instead carefully described chick development in the egg, laying a foundation for modern embryology. Others in mid-17th century also began systematically studying organ function: for instance, Thomas Wharton described endocrine glands (1656) and Thomas Bartholin in Copenhagen discovered the thoracic duct of the lymphatic system (1652). In 1620, the Italian anatomist Gaspare Aselli had already identified lacteal vessels (lymphatics of the gut). Such findings gradually eroded the old Galenic notion of physiology as movement of mystical “pneumas” or humors, replacing it with concrete descriptions of organs and fluids.

It should be mentioned that Descartes himself attempted a comprehensive physiological treatise, L’Homme (“Treatise of Man”), which he wrote in the 1630s. In this work (only published posthumously in 1662), Descartes presented the human body as a machine and gave the first description of what we now recognize as reflexes. He explained, for example, how touching a hot flame would trigger a rapid, automatic withdrawal of the hand, without the intervention of conscious thought – a concept very close to our modern understanding of reflex action. This was arguably the first textbook of physiology in Europe, mapping out functions like circulation, digestion, sensation, and motion in mechanistic terms. Though Descartes stopped short of publishing it in his lifetime (fearing religious backlash for some of his ideas), manuscript copies circulated among intellectuals. His mechanistic physiology and emphasis on the pineal gland as the mind-body interface, while not empirically proven, stimulated debate and further investigation into neuroanatomy and bodily control.

In summary, by 1650 Western medicine had gained a much clearer anatomical map of the human body and a nascent understanding of how major systems function. The circulation of blood was demonstrated, the true structure of organs was better known from dissections, and the stage was set for linking structure to function. This new knowledge did not immediately cure diseases, but it provided the scientific underpinnings for future progress. It also marked a dramatic departure from basing medicine purely on ancient books – discovery and innovation were now possible and celebrated.

Medical Practice and Treatment in the Early 17th Century

While scientific knowledge was advancing, everyday medical practice during Descartes’s lifetime remained a mix of old and new. Traditional remedies and procedures continued to be used widely, and effective new treatments were few. Bloodletting was still a go-to therapy for countless ailments – fever, inflammation, headache, etc. – under the rationale of removing excess blood (the “hot” humor) or calming the body. Physicians carried lancets and leech jars as standard equipment. Purging of the bowels with laxatives or inducing vomiting were common to expel supposed noxious humors. Such methods persisted in part because, lacking precise understanding of disease, doctors felt they must “do something,” and these interventions fit the humoral theory. Unfortunately, aggressive bleeding and purging often weakened patients further, but this would not be fully recognized until much later.

Herbal medicine was another mainstay of 17th-century practice. Pharmacists (apothecaries) and physicians dispensed a vast array of plant-based concoctions: willow bark for pain, foxglove (in folk use) for dropsy, and so on – though the active chemical principles (like salicylates in willow or digitalis in foxglove) were not yet isolated. Many remedies came from medieval herbals or classical sources like Dioscorides. However, the 17th century also introduced new medicinal substances from global exploration and alchemical laboratories. A noteworthy example is cinchona bark (Peruvian bark), which Jesuit missionaries brought from South America to Europe in the 1630s–1640s. This bark, rich in quinine, was found to markedly reduce malarial fevers. By the 1650s it was known in England as “Jesuits’ powder”, available from apothecaries as an expensive but life-saving remedy. The Italian physician Ramazzini in the 17th century even lauded Peruvian bark as a discovery in medicine on par with the value of gold and silver from the New World. This was one of the few really effective specific treatments of the era, in contrast to the largely symptomatic or purgative treatments of humoral medicine.

Likewise, chemical drugs were being tested and adopted. Antimony-based compounds (like “antimony wine” or emetic tartar) could induce vomiting or sweating and became popular remedies for various illnesses. These often originated from Paracelsian chemists. There was significant controversy around antimony: the Faculty of Medicine in Paris had banned its use in 1566 as poisonous, but by 1650 many practitioners were using it, and a public debate – the so-called “antimony war” – raged between conservative Galenists and Paracelsians. In 1658, when the young King Louis XIV survived a serious illness after being treated with antimony, the tide turned decisively in favor of chemical remedies, and eventually the prohibition was lifted. Mercury was another toxic substance routinely used – most famously in the treatment of syphilis, a disease that first struck Europe in the late 15th century. By the 17th century, mercurial ointments or elixirs were standard to treat syphilis (despite mercury’s dreadful side effects) because no better cure existed. These examples illustrate how therapeutics in Descartes’s time were still primitive and often as harmful as the diseases, yet innovation was slowly occurring through trial and error.

Public health measures in this era were rudimentary. Europe suffered recurring epidemics of plague (for instance, outbreaks in 1603 London, 1629–31 northern Italy, and 1647–48 in Spain) with staggering mortality. Without knowledge of bacteria (the plague bacillus) or effective cure, authorities resorted to medieval tactics: quarantine of the sick, travel restrictions, burning barrels of tar or herbs to purify “miasmatic” air, and prayer. Cities had “pest houses” to isolate the ill, but doctors had no real tools beyond watching for God’s will. Descartes himself fled Paris in 1628 partly to avoid an outbreak. Smallpox was another dreaded killer – though it struck mostly children, its survivors often bore scars for life. In the 17th century, smallpox was ubiquitous and preventive inoculation (variolation) had not yet reached Europe (it would only be introduced from Turkey in the early 18th century). The lack of preventive measures meant that the average life expectancy was low (many people died before 40), and infant and child mortality were very high by modern standards.

Surgical practice remained quite limited in Descartes’s time. Surgery was considered a manual craft, separate from the “learned” art of physic (medicine). Most surgeons lacked university education and instead learned through apprenticeships. They handled trauma, amputations, draining abscesses, setting fractures, and removing bladder stones. However, without anesthetics (not developed until the 19th century) or antiseptic technique (late 19th century), surgeries were excruciating and often lethal due to pain, shock, or post-operative infection. Surgeons like Paré had introduced important techniques as noted, and in 1628 the first human blood transfusion experiments were attempted (unsuccessfully) in France by Jacques Guillemeau and others using lamb’s blood – but these were isolated curiosities. Even something as basic as tooth extraction or bloodletting was often done by barber-surgeons with sharp tools, with no pain relief except perhaps alcohol or opium. Thus, despite scientific advances in understanding the body, treatment and surgical outcomes remained harsh by today’s standards. Many patients preferred to trust traditional healers or remedies for as long as possible before submitting to a surgeon’s knife.

One bright development in practice was the increasing emphasis on clinical observation and documentation of cases. Physicians began writing more detailed case histories and attempting to classify diseases by patterns of symptoms rather than just treating imbalances. The English physician Thomas Sydenham (1624–1689), a younger contemporary of Descartes, exemplified this approach. Sydenham, sometimes called the “English Hippocrates,” advocated for careful observation of the patient and the course of illness, de-emphasizing complex theory and polypharmacy. He believed that physicians should “return to the bedside” and learn from the natural history of diseases. In practice, this meant identifying specific disease entities (like differentiating scarlet fever from measles, which Sydenham did) and choosing simple treatments that alleviate symptoms. This empirical, disease-focused approach was a reaction against the fruitless argument of iatrochemists vs. iatromechanists. By the late 17th century, thanks to Sydenham and others, there was a partial swing back to Hippocratic principles: valuing experience over dogma, and the idea that the physician’s duty is to aid the body’s own healing (“vis medicatrix naturae” – the healing power of nature), a concept even Descartes acknowledged.

Medical Education and Institutions in Descartes’s Era

During Descartes’s lifetime, the institutional landscape of medicine was also evolving gradually. Universities such as Padua, Leiden, Paris, Oxford, and Leiden were the centers for training physicians (as well as a few pioneering surgeons). Padua in particular stood out as a progressive medical school around 1600; it was there that many innovators studied or taught – Vesalius had lectured at Padua, and later Fabricius, Harvey, and Santorio all worked there. The curricula still taught Galenic theory but increasingly incorporated anatomy demonstrations and even discussions of new findings. In some regions, especially Protestant northern Europe, there was slightly more intellectual freedom to question tradition (for instance, Leiden University under Professor Franciscus Sylvius actively taught chemistry in medicine by mid-century).

Professional organizations played a role in regulating practice: the Royal College of Physicians in London, the Collège de Saint Côme for surgeons in Paris, guilds for apothecaries, etc., which tried to maintain standards (often by enforcing adherence to accepted practices). These bodies sometimes resisted innovation – for example, the Paris Faculty of Medicine’s initial ban on chemical remedies shows the institutional conservatism that innovators faced. However, by mid-17th century, the winds were changing. In 1660 (a decade after Descartes’s death), the Royal Society of London was founded – a scientific academy where physicians and natural philosophers met to share research (several founding members were medically trained, like Christopher Wren and William Petty). Descartes himself had corresponded with informal networks of savants (e.g., Marin Mersenne’s circle) which were precursors to such societies. The first medical journals wouldn’t appear until the 18th century, but correspondence in Latin among learned men helped spread new medical ideas across borders. For example, Harvey’s discovery quickly became known in Europe through personal letters and scholarly visits even before it was fully accepted.

Hospitals in the early 17th century were mostly charitable institutions run by religious orders or municipalities, meant for the poor, pilgrims, or those with no family – places like Hôtel-Dieu in Paris or various infirmaries. They were not centers of cutting-edge medical treatment; in fact, they often had dreadful sanitary conditions and served more as shelters. Wealthy patients were treated at home by private physicians. There was little in terms of organized public health beyond responses to epidemics. One noteworthy initiative was the quarantine stations (lazzaretti) set up in Italian port cities (like Venice) to screen and isolate travelers during plague times – an early form of public health policy which had started in the late medieval period and continued in the 17th century.

An important social aspect was that women in medicine were mostly excluded from formal practice (with the exception of midwifery). Women could not attend universities or join physician colleges, but they served as informal healers, midwives, and nurses. In the 17th century a few women, like Louise Bourgeois in France (a royal midwife who published a midwifery textbook in 1609), gained recognition. Overall, however, the professionalization of medicine was a male-dominated enterprise at this time.

Conclusion: A Field in Transition

In sum, during René Descartes’s lifetime (1596–1650), Western medical science straddled the medieval and modern. On one hand, the daily practice of medicine was still governed by age-old traditions – the theory of humors, reliance on bloodletting and herbal concoctions, and the authority of classical texts. Remedies were largely ineffective or even detrimental, and people had little defense against scourges like plague or smallpox. On the other hand, this period witnessed remarkable progress in understanding the human body and questioning medical dogma. The Renaissance legacy of Vesalius and others had given physicians accurate anatomy. The Scientific Revolution ethos led Harvey to apply experimental methods, resulting in the discovery of blood circulation – “the supreme 17th-century achievement in medicine”. Across Europe, forward-thinking individuals embraced new models of knowledge, whether chemical or mechanical, demonstrating an unprecedented willingness to explain life processes in natural, rational terms rather than mystical ones. Descartes’s own mechanistic view of the body as a machine exemplified this new mindset and had significant repercussions in medicine, paving the way for fields like physiology and neurology.

By 1650, the concept of disease was slowly shifting: physicians began to seek specific causes for specific diseases (foreshadowing germ theory), and they started to categorize diseases by clinical observation (foreshadowing modern diagnostics), moving away from treating the ill as a uniform imbalance of humors. The older generation still clung to humoral and astrological explanations, but a younger generation was “discarding the past and adopting new ideas”. In practice, patients of the time might not yet have benefited greatly from these scientific advances, but the stage was set for rapid progress. The mechanisms of circulation were known, anatomy was mapped, and the value of empirical research was established in medicine.

In the years shortly after Descartes, these trends accelerated: the later 17th century would bring the first microscopes revealing micro-organisms, Sydenham’s solidification of clinical medicine, and the chemistry of Boyle and others inching toward biochemical understanding. Thus, the status of Western medical science in Descartes’s lifetime was one of dynamic transformation. It was a period in which medicine moved away from being an art based on ancient doctrines and towards becoming a science based on observation and experiment. The coexistence of bleeding bowls and microscopes, of herbal potions and mechanical models of the body, might seem paradoxical, but it captures the essence of that era. Western medicine was, by 1650, evolving rapidly – still burdened by its past, yet propelled by new discoveries that would eventually yield the modern medical science we know today.