The famous philosophical quote "I think, therefore I am" is attributed to René Descartes, a French philosopher, mathematician, and scientist. This phrase originally appears in Latin as "Cogito, ergo sum." It encapsulates Descartes' foundational principle of modern Western philosophy, signifying that the act of thinking is proof of one's existence. In his work "Meditations on First Philosophy," Descartes sought to establish certainty in knowledge by doubting everything he previously accepted as true, leading to this pivotal realization. His ideas laid the groundwork for later philosophical inquiry and significantly influenced the development of rationalism and epistemology.