What does cogito mean?
The cogito is one of the most famous ideas in Western philosophy: the principle, articulated by René Descartes in the seventeenth century, that the act of thinking provides irrefutable evidence of one's own existence. From the Latin phrase 'cogito, ergo sum' — "I think, therefore I am" — it names the single certainty Descartes believed could withstand total skepticism: even if everything else is an illusion, the fact that one is thinking cannot be denied, because doubting is itself a form of thought. In modern usage, 'cogito' functions as a noun, usually capitalized on its Latin pedigree and appearing mostly in philosophical, academic, or intellectual discussion. It often stands shorthand for Descartes' whole foundational argument, sometimes called the Cartesian cogito. The word carries connotations of rigorous reasoning and self-awareness, and it remains a touchstone in debates about consciousness, certainty, and the nature of mind.
nounThe fundamental act of thinking as an indubitable proof of one's own existence; specifically, Descartes' principle 'cogito, ergo sum' ("I think, therefore I am"), used in philosophy to denote the self-verifying awareness of one's own thought.
- In philosophy, the self-evident awareness of one's own thinking, especially as formulated by Descartes as 'cogito, ergo sum', serving as the foundation of certain knowledge.
- By extension, any instance of conscious thought regarded as proof of a thinker's existence.
"For Descartes, the cogito was the one truth that could survive even the most radical doubt."
"The professor began her lecture on modern philosophy with a careful unpacking of the cogito."
"Every time we entertain a doubt, we enact the cogito — the doubting itself is thinking."
Rarely used; the word almost always appears in the singular, referring to Descartes' single principle.
"The seminar compared several interpretations of different thinkers' cogitos."
René Descartes doubted everything he could — his senses, his body, even the world around him — but found one thing he could not doubt: the very fact that he was thinking.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of cogito
Cogito comes directly from the Latin first-person form 'cogito', meaning "I think", derived from the verb 'cogitare' (to think, to ponder). That verb likely combines the prefix 'co-' ('together') with the root of 'agere' ('to drive, to do'), suggesting an original sense of driving thoughts together. René Descartes made the word famous through the phrase 'cogito, ergo sum', introduced in his Discourse on the Method (1637) and later developed in his Meditations. It shares this deep Latin root 'agere' with English words such as 'agent', 'agile', and 'coagulate'.
Related word forms
How cogito is actually used
Cogito is primarily a technical term of philosophy and is rare outside academic writing and intellectual discussion. It is almost always used in connection with Descartes and is typically italicized when treated as the Latin phrase rather than the English noun.
Easily confused with cogito
Cogitate is a verb meaning to think deeply or ponder, while cogito is a noun referring to the philosophical principle that thinking proves one's existence.