Fang Yizhi was a prominent Chinese mathematician and astronomer during the Ming Dynasty. He is best known for his work in mathematics, particularly in the field of geometry and number theory. His contributions helped lay the groundwork for future developments in these areas. In addition to his mathematical achievements, Fang Yizhi was also an advocate for scientific inquiry and rational thought. He emphasized the importance of observation and experimentation in understanding the natural world, which was a significant shift from traditional beliefs of his time. His ideas influenced later scholars and contributed to the advancement of science in China.