Cogito ergo sum | I think therefore I am – René Descartes

Cogito ergo sum is a Latin phrase (Old Latin as ˈkoːɡitoː ˈɛrɡoː ˈsʊm). This philosophical statement was written by René Descartes in his work, Principles of Philosophy (1644). The Latin phrase can translate as “I think, therefore I am”, and some of others translate as “I think, therefore I exist”. However, it was originally appeared in French as je pense, donc je suis in Descartes’ work “Discourse on the Method” (1637). Due to its important, it took a place in Western philosophy, and it is known as “the cogito ergo sum argument" and simply as the cogito.

Cogito ergo sum | I think therefore I am

This proposition opens paths to analysis of existence and doubt. Therefore, it became one of fundamental elements in philosophical world. Philosophy doubts subjects and asks questions, and then comes to conclusion(s) or gives choices. Existence is one of major subjects; especially it dealt with existence of god. Still it is not concluded. Majority doubts the existence of god. Likewise, our existence is doubtful too. Philosophy questions our existence in the lights of perception and other concepts. But Descartes concluded our existence by the cogito. His idea can interpret as follows:

I think – There is a subject, “I” and a verb, “think”.
The subject “I” is able to think. – The subject can produce an action (verb).
An action (think) cannot function without subject (I).
There is a need for existence of subject to perform an action.
Therefore, subject “I” is existing.

Therefore, our existence is real and it is not doubtful concept. However, it received negative criticisms from scholars. Some of them argued that it is a psychological appeal and self-rationalization, not logical argument. We are unable to deny our existence and impossible to think "I do not exist". Apart from mixed criticisms, the cogito has a better existence in philosophy.

When we compare the cogito and Socrates’ phrase I know that I know nothing, I would thumb up for Socrates. He was neither self- rationalizer nor self-logical arguer.

I know Vs the cogito

Here is a simple summary of comparison of two phrases.

Phrase	I think, therefore I am	I know that I know nothing
Philosopher	René Descartes (1596 – 1650)	Socrates (470 – 399 BC)
Origin of language	Latin	Greek
Region	Western	Western
Type	Epistemology, metaphysics	Epistemology
Category	Thought (self-existence & doubt)	Self-referential paradoxes
Logic	Supports proposition only	No
Psychology	Rationalization	Ignorance
Philosophical arguments	Yes	No