Who is known as the father of modern rationalism?

Rene Descartes is widely recognized as the father of modern rationalism because he established a foundational framework for understanding knowledge and existence through reason and skepticism. His famous statement "Cogito, ergo sum" (I think, therefore I am) emphasizes the role of doubt and rational thought in the pursuit of knowledge. Descartes argued that knowledge should be built on clear and distinct ideas, which laid the groundwork for modern philosophy and influenced various fields, including mathematics and science.

Additionally, Descartes' works, such as "Meditations on First Philosophy," delve into the nature of reality and consciousness, underpinning rationalist thought that emphasizes the use of reason as the primary source of knowledge. This approach diverges from empirical methods, suggesting that certain knowledge can be attained independent of sensory experience.