"I think, Therefore I Am", What Does This Descartes Quote Mean?

"I think, therefore I am" or "cogito ergo sum" is related to conceiving one's own existence. Let's delve into this quote by René Descartes.
"I think, Therefore I Am", What Does This Descartes Quote Mean?

Last update: 18 October, 2024

The meaning of this famous Descartes quote may seem obvious, along with the fact that we are rational beings with the ability to think about the world around us. However, we say it with all the cultural baggage that precedes us. There was a time when this wasn’t the case, until Descartes arrived on the scene. He’s credited with a remarkable discovery summarized in the phrase: “I think, therefore I am.”

In this article, we’ll explore the meaning of this discovery and the doctrine behind this intellectual, who’s considered one of the most important philosophers of the 17th century. Let’s get started!

The context of the philosophy of René Descartes

René Descartes was a renowned philosopher and physicist of great importance for the development of rationalism. This current assumes that human beings have the capacity to know through our reason. The relevance of his work lies in the fact that he was one of the first to build the bases and rules to achieve sure and true knowledge.

Firstly, Descartes sought to emancipate the subject from the bonds of dogmatic knowledge. This means that the sources of knowledge must come from ourselves and not from religion or a philosophy built on flimsy foundations.

At the same time, he looked to find that sure path for the development of philosophy in particular and science in general. Therefore, in his various books, he proposed to build the foundations of a new rationalist philosophy. We can name the following most notable works by this philosopher:

  • Rules for the Direction of the Mind (1626-1628)
  • Discourse on the Method (1637)
  • Metaphysical Meditations (1641)
  • Principles of Philosophy (1644)
  • Passions of the Soul (1649)

In this article, we’ll focus on the Discourse on the Method and Metaphysical Meditations. This is because the famous Descartes quote, “I think, therefore I am,” appears in both of them.



The meaning of the Descartes quote, “I think, therefore I am”

The original formulation of the Descartes quote, “I think, therefore I am,” is written in Latin as cogito ergo sum. It means that in the act of thinking, a person can conceive their own existence. That is, this reflection considers that being and existing are mutually identified, and one can’t be without the other.

To interpret the phrase as a whole, it’s a good idea to disassemble it into parts. In this way, the word cogito is the act of thinking. For its part, ergo means later, although it’s not interpreted with an adverb of time, rather, it’s a simultaneous experience. Finally, sum means to be.

“And having noticed that there is nothing at all in this, I think, therefore I am, which assures me that I am speaking the truth except that I see very clearly that in order to think one must exist.”[/atomik -quote]»

As an article in the journal Studium maintains, Descartes intuits a concrete existence linked to the act of thinking. In other words, it’s an internal experience that’s the product of a rigorous philosophical method known as methodical doubt.

It’s worth mentioning that the phrase appears for the first time in Descartes’ work Discourse on the Method, specifically, in the fourth part. In it, the philosopher proceeds to make a summary of what will later be explained with greater precision in the Metaphysical Meditations.

Methodical doubt as a starting point to reach cogito ergo sum

Descartes arrives at cogito ergo sum through methodical doubt. But what does this consist of? This is a provisional and necessary doubt to carry out the philosophical objective that he set for himself. It consists of discovering the sure path for the development of philosophy and science.

This doubt is characterized by considering all our past opinions as false, especially those that come from our senses. Furthermore, the act of doubting represents freedom from the ties of the past that constricted our consciousness.

It’s important to highlight that Descartes considers doubt as an act of thought. In this regard, doubt is a source to discover cogito ergo sum, as by doubting, we make use of our thinking, reaffirming not only our thinking but also our own existence. Let’s remember at this point that thinking and existing are connected.

In this way, cogito ergo sum assures a doubting self. It arises from the very act of doubting.

“I think, therefore I am”: Clarity and Distinction

One of the most important rules of thought for Descartes is clarity and distinction. Furthermore, it’s the first that the philosopher exposes in Discourse on the Method. The fundamental thing about it is that it represents a criterion of truth. This means that everything that I conceive as clear and distinct is, necessarily, true.

In this way, said clarity and distinction are an immediate intuition that our reason captures spontaneously. In this aspect, Descartes considers intuition to be an absolute truth.

The first intuition he discovers is “I think, therefore I am.” Therefore, he represents the first absolute truth that serves as a model to find the others.

The philosophical anthropology of Descartes

Already, at this point, we can say that Descartes defines the human being as a thinking reality. In Latin, this is known as res cogitans. Therefore, the Descartes quote, “I think, therefore I am,” is an immediate intuition that clearly sees that in order to think, one must exist. In this way, we apprehend our existence in the very act of thought.

So, according to this philosopher, thought is not only an essential attribute of the human being, it’s the most important. The most notable thing about this is that it not only defines the human being but, furthermore, the evidence is such that it can’t be doubted.

The importance of Descartes’ philosophy

René Descartes is considered the father of modernity, but the influence of his thought isn’t limited to this. In this regard, an article published by the journal CIENCIA ergo-sum reviews some relevant issues to consider in Cartesian philosophy.

Firstly, there’s no doubt about the revolution of the Cartesian theory of autonomous reason. It’s represented through the phrase cogito ergo sum. In this way, Descartes is considered to have given rise to the notion of I, that is, a subjectivity thrown into the world.

Furthermore, he introduces a new conception of the human being, defined through his thinking activity. This idea will endure not only in the development of later philosophy, but also in science itself. This is because scientists began to address the world with as pure a view as possible.


To learn more: Descartes and Dreams


Descartes: A revolutionary philosopher

The philosophy of René Descartes represented a radical change in the way of thinking about human beings and science in general. Born on March 31, 1596 at La Haye in Touraine, France, his philosophical goal was to lay the foundations for science in general and philosophy in particular. This earned him the fame of being one of the most important thinkers of the 17th century.

With the formulation of cogito ergo sum, he opened a new horizon of thought that put human reason at its center. Not only that, Descartes also systematically developed a method with which one could hope to find the truth without any error.


All cited sources were thoroughly reviewed by our team to ensure their quality, reliability, currency, and validity. The bibliography of this article was considered reliable and of academic or scientific accuracy.


  • Damasio, A. (2020). El error de Descartes. Crítica. Daturi, D. E. (2011). El sentido de la obra de Descartes a la luz de la tradición y su valor prospectivo. CIENCIA ergo-sum, Revista Científica Multidisciplinaria de Prospectiva18(3), 275-282. https://cienciaergosum.uaemex.mx/article/view/7061
  • Descartes, R. (2020). Discurso del Método. AMA.
  • Descartes, R. (1649). Las pasiones del alma. Tecnos.
  • Descartes, R. (2020). Meditaciones metafísicas. Editorial Verbum.
  • Encyclopedia Britannica. (8 de septiembre de 2023). Cogito, ergo sumhttps://www.britannica.com/topic/cogito-ergo-sum
  • Marcélus, G. D. (2004). El pensamiento como modo de descubrir nuestro verdadero ser según el planteamiento del cogito ergo sum. Studium. Filosofía y Teología7(14), 281–306. https://revistas.unsta.edu.ar/index.php/Studium/article/view/885
  • Marcélus, G. D. (2006). Estudio hermenéutico y análisis interpretativo de nociones fundamentales al planteamiento cartesiano del “cogito ergo sum”. Studium. Filosofía y Teología9(17), 79–111. https://revistas.unsta.edu.ar/index.php/Studium/article/view/713
  • Shorto, R. (2020). Descartes’ Bones: A Skeletal History of the Conflict between Faith and Reason. Vintage.
  • Sorell, T. (2020). Descartes: A Very Short Introduction. Oxford University Press.

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