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Uniting Astronomy and Physics: Isaac Newton
Although the motions of celestial bodies had been qualitatively explained in physical terms since Aristotle introduced celestial movers in his Metaphysics and a fifth element in his On the Heavens, Johannes Kepler was the first to attempt to derive mathematical predictions of celestial motions from assumed physical causes. This led to the discovery of the three laws of planetary motion that carry his name.
Isaac Newton developed further ties between physics and astronomy through his law of universal gravitation. Realizing that the same force that attracted objects to the surface of Earth held the moon in orbit around the Earth, Newton was able to explain, in one theoretical framework, all known gravitational phenomena. Newton’s Principia (1687) formulated the laws of motion and universal gravitation, which dominated scientists’ view of the physical universe for the next three centuries. By deriving Kepler’s laws of planetary motion from his mathematical description of gravity, and then using the same principles to account for the trajectories of comets, the tides, the precession of the equinoxes, and other phenomena, Newton removed the last doubts about the validity of the heliocentric model of the cosmos. This work also demonstrated that the motion of objects on Earth and of celestial bodies could be described by the same principles. His laws of motion were to be the solid foundation of mechanics; his law of universal gravitation combined terrestrial and celestial mechanics into one great system that seemed to be able to describe the whole world in mathematical formulae.
Jan Matejko, Astronomer Copernicus, or Conversations with God, 1873: Oil painting by the Polish artist Jan Matejko depicting Nicolaus Copernicus observing the heavens from a balcony by a tower near the cathedral in Frombork. Currently, the painting is in the collection of the Jagiellonian University of Cracow, which purchased it from a private owner with money donated by the Polish public.
The Medical Renaissance
The Renaissance period witnessed groundbreaking developments in medical sciences, including advancements in human anatomy, physiology, surgery, dentistry, and microbiology.
- During the Renaissance, experimental investigation, particularly in the field of dissection and body examination, advanced the knowledge of human anatomy and modernized medical research.
- De humani corporis fabrica by Andreas Vesalius emphasized the priority of dissection and what has come to be called the “anatomical” view of the body. It laid the foundations for the modern study of human anatomy.
- Further groundbreaking work was carried out by William Harvey, who published De Motu Cordis in 1628. Harvey made a detailed analysis of the overall structure of the heart and blood circulation.
- French surgeon Ambroise Paré (c. 1510-1590) is considered one of the fathers of surgery and modern forensic pathology, and a pioneer in surgical techniques and battlefield medicine, especially in the treatment of wounds.
- Herman Boerhaave (1668-1738) is regarded as the founder of clinical teaching, and of the modern academic hospital. He is sometimes referred to as “the father of physiology.”
- French physician Pierre Fauchard started dentistry science as we know it today, and he has been named “the father of modern dentistry.”
- humorism: A system of medicine detailing the makeup and workings of the human body, adopted by the Indian Ayurveda system of medicine, and Ancient Greek and Roman physicians and philosophers. It posits that an excess or deficiency of any of four distinct bodily fluids in a person—known as humors or humours—directly influences their temperament and health.
- Andreas Vesalius: A Belgian anatomist (1514-1564), physician, and author of one of the most influential books on human anatomy, De humani corporis fabrica (On the Fabric of the Human Body).
- Galen: A prominent Greek physician (129 CE-c. 216 CE), surgeon, and philosopher in the Roman Empire.
Arguably the most accomplished of all medical researchers of antiquity, he influenced the development of various scientific disciplines, including anatomy, physiology, pathology, pharmacology, and neurology, as well as philosophy and logic.
- Ambroise Paré: A French surgeon (1510-1590) who is considered one of the fathers of surgery and modern forensic pathology, and a pioneer in surgical techniques and battlefield medicine, especially in the treatment of wounds.
- William Harvey: An English physician (1578-1657), and the first to describe completely and in detail the systemic circulation and properties of blood being pumped to the brain and body by the heart.
The Renaissance and Medical Sciences
The Renaissance brought an intense focus on varied scholarship to Christian Europe. A major effort to translate the Arabic and Greek scientific works into Latin emerged, and Europeans gradually became experts not only in the ancient writings of the Romans and Greeks, but also in the contemporary writings of Islamic scientists. During the later centuries of the Renaissance, which overlapped with the scientific revolution, experimental investigation, particularly in the field of dissection and body examination, advanced the knowledge of human anatomy. Other developments of the period also contributed to the modernization of medical research, including printed books that allowed for a wider distribution of medical ideas and anatomical diagrams, more open attitudes of Renaissance humanism, and the Church’s diminishing impact on the teachings of the medical profession and universities. In addition, the invention and popularization of microscope in the 17th century greatly advanced medical research.
Human Anatomy
The writings of ancient Greek physician Galen had dominated European thinking in medicine. Galen’s understanding of anatomy and medicine was principally influenced by the then-current theory of humorism (also known as the four humors: black bile, yellow bile, blood, and phlegm), as advanced by ancient Greek physicians, such as Hippocrates. His theories dominated and influenced western medical science for more than 1,300 years. His anatomical reports, based mainly on dissection of monkeys and pigs, remained uncontested until 1543, when printed descriptions and illustrations of human dissections were published in the seminal work De humani corporis fabrica by Andreas Vesalius, who first demonstrated the mistakes in the Galenic model. His anatomical teachings were based upon the dissection of human corpses, rather than the animal dissections that Galen had used as a guide. Vesalius’ work emphasized the priority of dissection and what has come to be called the “anatomical” view of the body, seeing human internal functioning as an essentially corporeal structure filled with organs arranged in three-dimensional space. This was in stark contrast to many of the anatomical models used previously.
Further groundbreaking work was carried out by William Harvey, who published De Motu Cordis in 1628. Harvey made a detailed analysis of the overall structure of the heart, going on to an analysis of the arteries, showing how their pulsation depends upon the contraction of the left ventricle, while the contraction of the right ventricle propels its charge of blood into the pulmonary artery. He noticed that the two ventricles move together almost simultaneously and not independently like had been thought previously by his predecessors. Harvey also estimated the capacity of the heart, how much blood is expelled through each pump of the heart, and the number of times the heart beats in a half an hour. From these estimations, he went on to prove how the blood circulated in a circle.
Other Medical Advances
Various other advances in medical understanding and practice were made. French surgeon Ambroise Paré (c. 1510-1590) is considered one of the fathers of surgery and modern forensic pathology, and a pioneer in surgical techniques and battlefield medicine, especially in the treatment of wounds. He was also an anatomist and invented several surgical instruments, and was part of the Parisian Barber Surgeon guild. Paré was also an important figure in the progress of obstetrics in the middle of the 16th century.
Herman Boerhaave (1668-1738), a Dutch botanist, chemist, Christian humanist and physician of European fame, is regarded as the founder of clinical teaching and of the modern academic hospital. He is sometimes referred to as “the father of physiology,” along with the Venetian physician Santorio Santorio (1561-1636), who introduced the quantitative approach into medicine, and with his pupil Albrecht von Haller (1708-1777). He is best known for demonstrating the relation of symptoms to lesions and, in addition, he was the first to isolate the chemical urea from urine. He was the first physician that put thermometer measurements to clinical practice.
Bacteria and protists were first observed with a microscope by Antonie van Leeuwenhoek in 1676, initiating the scientific field of microbiology.
French physician Pierre Fauchard started dentistry science as we know it today, and he has been named “the father of modern dentistry.” He is widely known for writing the first complete scientific description of dentistry, Le Chirurgien Dentiste (“The Surgeon Dentist”), published in 1728. The book described basic oral anatomy and function, signs and symptoms of oral pathology, operative methods for removing decay and restoring teeth, periodontal disease (pyorrhea), orthodontics, replacement of missing teeth, and tooth transplantation.
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