# I think, therefore I am

> English word · Phrase

## Definitions
1. I am able to think, therefore I exist; a proof of existence based on the fact that someone capable of any form of thought necessarily exists.

## Etymology
Calque of French je pense, donc je suis or perhaps of Latin cōgitō, ergō sum. First written in French by René Descartes, a 17th century French philosopher, in Discourse on the Method (1637) as je pense donc je suis, which he later expressed in Latin in Principles of Philosophy (1644).

## Source
Compiled from Wiktionary via kaikki.org (CC BY-SA). Data vintage: 2026-05-06.
Canonical page: https://plainspell.com/en/word/i-think-therefore-i-am