How did Aristotle’s ideas influence William Harvey?

William Harvey was significantly influenced by the ideas of the Greek philosopher Aristotle, whose works on animals Harvey studied and lectured on during the 17th century.12

Aristotle’s influence on Harvey is most notably seen in the use of a macrocosm/microcosm analogy to explain the circulation of blood. Harvey compared the human body (the microcosm) to the Earth’s weather cycle (the macrocosm). Just as the Sun heats water to create vapor that rises and falls as rain, Harvey theorized that the heart acts as the "Sun of the Microcosm," heating and changing the blood before it cools in the body's extremities.1

This Aristotelian framework helped Harvey address the fundamental question of how blood could be efficiently converted within a single system. While Harvey was a man of the late Renaissance who drew on alchemy and natural magic traditions, his engagement with Aristotle’s philosophy of nature remained a critical component of his scientific approach.12