Define Cogito, ergo sum.

"Cogito, ergo sum" is a Latin philosophical proposition that translates to "I think, therefore I am." Coined by René Descartes, a 17th-century philosopher and mathematician, this statement encapsulates a foundational moment in his philosophy and serves as a starting point for his quest for certain and indubitable knowledge.

Descartes introduced this proposition in the context of methodical doubt, where he sought to doubt everything that could be doubted in order to establish an unshakeable foundation for knowledge. Amidst this doubt, he realized that the very act of doubt itself required a thinking subject. The cogito, or the thinking self, became the only certainty in the face of radical skepticism.

The statement asserts that the existence of the thinking self is undeniable, as doubt or any mental activity presupposes a thinking subject. Therefore, the act of thinking serves as proof of one's own existence. "Cogito, ergo sum" is not just a statement about existence but a declaration of the certainty of self-awareness and consciousness as the foundational element upon which Descartes would build his philosophical system. This proposition is a pivotal moment in the history of philosophy, marking the beginning of modern Western philosophy and influencing subsequent thinkers.