Quote by René Descartes: “Cogito, ergo sum.”

This Latin phrase, meaning 'I think, therefore I am,' establishes the fundamental certainty of one's own existence through the act of thinking. It asserts that the very act of doubting proves that a 'doubter' must exist, forming a bedrock of self-awareness and philosophical inquiry.

During the Scientific Revolution, Descartes sought a foundational truth amidst widespread skepticism and religious turmoil, aiming to establish certainty in knowledge.

French philosopher and mathematician whose Discourse on the Method and Meditations on First Philosophy founded modern rationalist philosophy. He is credited with establishing the mind-body problem and introducing the coordinate system that bears his name.