Concept

Cogito, ergo sum

Overview

The Latin cogito, ergo sum, usually translated into English as "I think, therefore I am", is the "first principle" of the philosophy of the French scientist and philosopher René Descartes. He originally published it in French as je pense, donc je suis in his 1637 Discourse on the Method, so as to reach a wider audience than Latin would have allowed. It later appeared in Latin in his Principles of Philosophy, and a similar phrase (ego sum, ego existo, 'I am, I exist') also featured prominently in his Meditations on First Philosophy. The dictum is also sometimes referred to as the cogito. As Descartes explained in a margin note, "we cannot doubt of our existence while we doubt." In the posthumously published The Search for Truth by Natural Light, he expanded it to dubito, ergo sum, vel, quod idem est, cogito, ergo sum ("I doubt, therefore I am—or what is the same—I think, therefore I am."). Antoine Léonard Thomas, in a 1765 essay in honor of Descartes, wrote in summary: dubito, ergo cogito, ergo sum ("I doubt, therefore I think, therefore I am.").

Descartes's statement became a fundamental element of Western philosophy, as it purported to provide a certain foundation for knowledge in the face of radical doubt. While other knowledge could be a figment of imagination, deception, or mistake, Descartes asserted that the very act of doubting one's own existence served—at minimum—as proof of the reality of one's own mind; there must be a thinking entity—in this case the self—for there to be a thought.

One critique of the dictum, first suggested by Pierre Gassendi, is that it presupposes that there is an "I" which must be doing the thinking. According to this line of criticism, the most that Descartes was entitled to say was that "thinking is occurring", not that "I am thinking".

Overview adapted from Wikipedia (CC BY-SA 4.0; see the article history for authors).

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I want more and more to perceive the necessary characters in things as the beautiful:—I shall thus be one of those who beautify things. _Amor fati_: let that henceforth be my love! I do not want to wage war with the ugly. I do not want to accuse, I do not want even to accuse the accusers. _Looking aside_, let that be my sole negation!
Friedrich Wilhelm Nietzsche, The Joyful Wisdom
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And yet it was as a self-evident or immediate truth that the 'Cogito, ergo sum,' of Descartes, the maxim on which may be said to hinge the whole interest of Modern Philosophy, was first stated by its author. The man who calls this a syllogism, must know little more about a syllogism than that the word 'Ergo' occurs in it. Where shall we look for the middle term?
Georg Wilhelm Friedrich Hegel, The Logic of Hegel
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Thus what is called "knowing," in the sense in which we can ascertain what other people "know," is a phenomenon exemplified in their physical behaviour, including spoken and written words. There is no reason--so Watson argues--to suppose that their knowledge IS anything beyond the habits shown in this behaviour: the inference that other people have something nonphysical called "mind" or "thought" is…
Bertrand Russell, The Analysis of Mind
States what Cogito, ergo sum is; names Cogito, ergo sum.
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Cogito, ergo sum

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