Q0054
“I think, therefore I am.” — René Descartes (Discourse on the Method IV (French)…)
Verified English quotation. Primary source: Discourse on the Method IV (French) / Principles of Philosophy (Latin). Theme: self.
English
I think, therefore I am.
Source and attribution
The archive attributes this English wording to Discourse on the Method IV (French) / Principles of Philosophy (Latin) and files it under Rationalism. That locator distinguishes the passage from loose internet attributions: readers can return to the named work or section to check translation, surrounding argument, and edition-specific wording.
About René Descartes
René Descartes (1596–1650) was a French mathematician and philosopher who helped launch early modern rationalism. Educated by Jesuits, he traveled as a soldier and settled for long periods in the Dutch Republic.
Interpretation
Descartes arrives at this in the Meditations rather than the Discourse, after methodically doubting everything that could be doubted. The claim is not an inference in the ordinary sense but something he finds he cannot doubt: the act of doubting establishes that there is one who doubts. Its significance is methodological — it becomes the fixed point from which the rest is to be rebuilt. Critics have argued it also smuggles in an unexamined "I".
Why it matters
The lasting move is the method rather than the sentence: doubt not in order to remain sceptical, but to find what survives it.
Concepts in this quote
- Self
- Philosophy quotes about self explore identity, responsibility, and the examined life—from Socrates’ unexamined life to modern phenomenology and existential authenticity.
- Reason
- Reason is the capacity to give and assess reasons—central to logic, science, ethics, and public argument.
How to cite this quotation
APA: René Descartes. (n.d.). I think, therefore I am. In Philosophy Blind Box. https://www.philosophydef.com/quotes/q0054
MLA: René Descartes. “I think, therefore I am..” Philosophy Blind Box, https://www.philosophydef.com/quotes/q0054.
Chicago: René Descartes. “I think, therefore I am..” Philosophy Blind Box. Accessed 2026. https://www.philosophydef.com/quotes/q0054.
Frequently asked questions
What is the source of the quotation “I think, therefore I am.”?
The passage is attributed to René Descartes, Discourse on the Method IV (French) / Principles of Philosophy (Latin). The archive attributes this English wording to Discourse on the Method IV (French) / Principles of Philosophy (Latin) and files it under Rationalism. That locator distinguishes the passage from loose internet attributions: readers can return to the named work or section to check translation, surrounding argument, and edition-specific wording.
What does René Descartes mean by self?
To ask about the self is to ask what persists through experience, what can be known from the first-person point of view, and how character is formed. Some traditions treat the self as a substantial soul; others as a stream of experience, a social role, or a practical center of agency. This passage enters that discussion through self, reason.