Descartes’ Famous Phrase: “I Think, Therefore I Am”

DescartesRené Descartes was an influential figure in the scientific revolution, and is considered to be the founder of modern philosophy. In 1637 Descartes wrote his well-known phrase: “I think, therefore I am.” He wrote this to rescue himself from doubt (the doubt of his own existence). He equated thinking with existing; therefore the awareness of his thoughts meant he was certain he existed. Descartes believed that the senses were unreliable, and ultimately, it was through the mind that one could arrive at the truth. Only reason could ascertain what was fundamentally true. He used examples such as: to the senses a stick in water appears to be bent, and the sun and the moon appear to be the same size.

The Evil Demon

For Descartes, doubt was central to his method of acquiring knowledge. He would tear down an idea through doubt and skepticism, and see if anything survived. His system has a likeness to the modern scientific method, as nothing is taken for granted. A hypothesis needs to be verified by tangible evidence in order to become accepted as knowledge.

He even went as far as imagining an evil demon, which created an illusion of the outside world and his own body. He concluded that if the deception was real, the fact that he was doubting his existence meant that someone was doing the doubting. Descartes concluded that the one thing he could know with absolute certainty was that he was thinking.

I Think…I Am

If we break up the phrase we see that Descartes’ statement is only a partial truth. To be aware of ones thoughts, there must be another dimension of consciousness apart from thought (something to witness the thoughts). The “I think” is separate from the “I am.” This was the insight of 20th century philosopher Jean-Paul Sartre when he examined Descartes’ statement.

To be thinking one must first be conscious. Although neuroscience is still trying to decipher the nature of consciousness, scientists are proceeding with the assumption that the secrets lie within the brain. Our experience is largely influenced by the activity in the brain. As it relates to consciousness, our thoughts are similar to our senses, as contributors to consciousness. Our thinking brain is a tool (a very valuable one), but it is not the totality of our existence.

The Power of Unconsciousness

There is still another level of existence that requires no thoughts or awareness. This is the unconscious processes that underlie all of existence, including ourselves. As familiar as conscious experience is to us and as complete as it feels, ultimate reality is much deeper. We generally accept that much of the world around us is without consciousness. For example, inanimate substances, plants, water, air, etc.

When it comes to humans (and animals to a lesser degree), we see ourselves as sentient beings. Yet consciousness emerges from a collection of unconscious processes. Focusing only on physiological functions, we can see how this works: we are unaware of our cells, blood, hearts, neurons, hormones, nerves and other bodily functions. Yet they all play a role in creating our experience. Clearly the brain has some critical input in regulating these activities, but that is mostly the unconscious brain.

It seems that Descartes’ conclusion was in effect describing the outer layer of self-awareness. Like an onion, the “I think” is the outer skin. The “I am” (consciousness beyond thought) is a deeper layer. And the core (unconscious life) is essentially the source that gives rise to experience, or as Descartes would have called it, existence. You could also say that Descartes was identifying solely with his thoughts. His sense of self was derived by his thinking mind, but he was much more than that.


References: Eckhart Tolle, A New Earth (New York: plume, 2006)

BBC Radio 4, In Our Time Philosophy: Cogito Ergo Sum (April 28, 2011)


7 responses to “Descartes’ Famous Phrase: “I Think, Therefore I Am”

  1. reasu\\\\\\\\geomoni

    . For instance, curves of “the first and simplest class” (viz., the circle, parabola, hyperbola, and ellipse) are described by a first or second degree polynomial equation and can be constructed by straight lines and circles. (cf. Bos 1996, Mahoney 1969) Following the methods delimited by Descartes, only the so-called “algebraic” curves, those with a corresponding closed polynomial, are to be included in the sphere of geometry. and these was observed by orof dr mircea orasanu and prof drd horoa orasanu in paper


  2. for Descartes considered many geometrical problems as observed prof dr mircea orasanu that observed that polubarinova kochina and vladimir smirnov have studied intensively EQ.GR I and prof dr . mircea orasanu studied Descartes GEOMETRY and LAGRANGIAN FORMS


  3. in many cases are observed that Descartes conclusions are used in Analytical Mechanics where prof dr constantin udriste a considered mant aspects as LAGRANGIAN NONHOLONOMIC BEHAVIOR and also cabiria andreian cazacu a used EQ Gr I in spaces complexes and also martin jurchescu and so called mathematicians or bruno a . boley cemal a. erringen same EQ gr 1 ,ans GR2


  4. with these we approach that Descartes as observed prof dr mircea orasanu as followed development and differential geometry and Chasles relations or Dupin formula


  5. as an important aspects are mentioned important situations as that of Descartes application in non holonomic problem where are used results that has been found by prof dr Const, Udriste using equations from analytical mechanics and articles published and concepts considered by prof drd horia orasanu ,and also many other studies. we add here that ideas of Descartes that have been used in mechanics also stand as based for Legendre equations and theorems or stokes results and theorems


  6. in many situations of Descartes concepts are used geometrical transforms and observed by prof drd horia orasanu and prof dr mircea orasanu and Conformal Transforms based by Legendre theories and Riemann theorem then using CONSTRAINTS OPTIMIZATIONS and accepted frm prof dr Constantin Udriste


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