Early reactions to Harvey's circulation theory: the impact on medicine

In early 17th century Europe, scientific concepts were still based largely on ancient philosophical and theological explanations. During this same era, however, experimentation began to take hold as a legitimate component of scientific investigation. In 1628, the English physician William Harvey announced a revolutionary theory stating that blood circulates repeatedly throughout the body. He relied on experimentation, comparative anatomy and calculation to arrive at his conclusions. His theory contrasted sharply with the accepted beliefs of the time, which were based on the 1400-year-old teachings of Galen and denied the presence of circulation. As with many new ideas, Harvey's circulation theory was received with a great deal of controversy among his colleagues. An examination of their motives reveals that many proponents agreed with his theory largely because of the logic of his argument and his use of experimentation and quantitative methods. However, some proponents agreed for religious, mystical and philosophical reasons, while some were convinced only because of the change in public opinion with time. Many opposed the circulation theory because of their rigid commitment to ancient doctrines, the questionable utility of experimentation, the lack of proof that capillaries exist, and a failure to recognize the clinical applications of his theory. Other opponents were motivated by personal resentments and professional "territorialism." Beyond the immediate issues and arguments, however, the controversy is important because it helped establish use of the scientific method.