“I think, therefore I am” is a famous philosophical statement by René Descartes, originally articulated in his work “Discourse on Method” as “Je pense, donc je suis” in French, and later reiterated in Latin in his “Principles of Philosophy” as “Cogito, ergo sum.”
This statement is the foundation of Descartes’ philosophy and part of his method of systematic doubt, a path to discover certain, indubitable knowledge. Descartes embarked on an intellectual journey to doubt all his beliefs to ascertain which ones could withstand this scrutiny.
The process led him to doubt various aspects of his knowledge, including sensory experience, physical reality, mathematical truths, and even his own existence. However, he then realized that the very act of doubting itself confirmed that he existed. If he was doubting, then he must be thinking, and if he was thinking, then he must exist. Even if he was being deceived by a malevolent force, as he postulated, the fact of the deception still required a thinking (and therefore existing) subject.
“I think, therefore I am” is a clear, immediate, and indubitable piece of knowledge that Descartes believed he could use as a firm foundation for building a reliable body of knowledge. This marked a turning point in philosophical method, leading to what is known as modern Western philosophy. It also established the significance of the thinking subject or consciousness in the philosophical discourse, a theme that continues to be central in philosophy and cognitive science.