During the Scientific Revolution, scholars began questioning long-held beliefs about the human body and medicine. For centuries, doctors in Europe based their understanding of anatomy on the teachings of Galen, an ancient Greek physician who had never dissected a human body. Instead, Galen studied animals and assumed that human anatomy was similar. This reliance on outdated knowledge hurt medical progress. New methods of observation and experimentation brought groundbreaking discoveries.

One of the first figures to challenge Galen’s ideas was Andreas Vesalius, a Flemish physician who believed that accurate knowledge of the human body could only come from direct observation. Vesalius conducted human dissections and documented his findings, which differed greatly from Galen’s descriptions. In 1543, Vesalius published On the Structure of the Human Body, a book filled with detailed drawings of muscles, bones, and organs based on his studies. His work was revolutionary, providing the first accurate anatomical textbook and setting a new standard for medical research.

Another discovery came from English physician William Harvey, who studied how blood circulates in the body. Prior to Harvey’s research, people believed that blood was constantly produced and consumed by the body. Through careful observation and experimentation, Harvey demonstrated that the heart works like a pump, circulating blood throughout the body in a continuous loop. His work, published in 1628, challenged traditional views and laid the foundation for modern cardiovascular science.