"Meditations on First Philosophy" is a foundational text by the philosopher René Descartes, where he explores the nature of existence and knowledge. In this work, Descartes famously declares, "I think, therefore I am," emphasizing that the act of thinking is proof of one's existence. He seeks to doubt everything he can to establish a firm foundation for true knowledge. Throughout the meditations, Descartes examines the existence of God and the distinction between the mind and the body. He argues that the mind is a separate entity from the physical world, laying the groundwork for modern philosophy and influencing future thinkers in the realms of metaphysics and epistemology.