Articles by Rene Descartes Review

Rene Descartes was a French philosopher, mathematician, and scientist who lived between 1596 and 1650. Often called the father of modern philosophy, Descartes introduced a shift in thinking from the empiricist school of thought in which people believed all knowledge ultimately comes to us through our senses to the rationalist school of thought in which it was believed that human reason was the source for all human knowledge. Through this development in thought, he was also the founder of modern-day mathematics and provided the framework for the study of the natural sciences.

In developing these ideas, Descartes wrote several books regarding the nature of existence and knowledge, providing us with plenty of material to study and has had a tremendous influence on those who have come after him. One of his most often quoted statements is “I think, therefore I am” which was published in his book entitled Discourse on Method, which was first published in 1637. By studying the writings that led up to this concept as expressed in Discourse on Method and comparing them with further attempts to refine this idea within Meditations on First Philosophy, one begins to conclude that Descartes’ account of what is necessary and what is sufficient for knowledge does not make sense.

Understanding that Descartes approached the world from an analytical, logically-based, metaphysical viewpoint, an aspect of Descartes that separated him from the thinkers of his time was his departure from traditional modes of thought in bringing together things that had not been done, or not been done often, in times past. “Before his time, philosophy had been dominated by the method of Scholasticism, which was entirely based on comparing and contrasting the views of recognized authorities” (Vincent 2003). “His philosophy refused to accept the Aristotelian and Scholastic traditions that had dominated philosophical thought throughout the Medieval period; it attempted to fully integrate philosophy with the ‘new sciences’, and Descartes changed the relationship between philosophy and theology. Such new directions of philosophy made Descartes into a revolutionary figure” (Baillet 1693). Instead of simply accepting the methods he’d been taught, Descartes believed “that all-natural science must be capable of being unified under mathematics, and that the world must be of such a nature as to admit of mathematical treatment” (Vincent 2003). Rather than working with thought as a separate entity divided from other disciplines such as math and the ‘natural philosophy’ that was the science of the day, Descartes worked instead to bring science together with philosophy.

Descartes was in the unique position of providing an alternative path for philosophy to take. “According to Descartes, the four rules of logic were: to accept as true only those conclusions which were clearly and distinctly known to be true; to divide difficulties under examination into as many parts as possible for their better solution; to conduct thought in order, and to proceed step by step from the simplest and easiest to know, to more complex language; and in every case to take a general view so as to be sure of having omitted nothing” (Kandaswamy 2006). Reading through these steps, the linkage of thought to mathematical methods of analysis can be clearly traced. “What suggested to Descartes that such a project made sense within the formalist framework was doubtless the stunning intellectual accomplishment represented by his analytic geometry, i.e., the reduction of the classical ‘science of space’ to a series of deductions within the algebraic ‘science of number’. Why should not something analogous be equally feasible for the emerging ‘science of nature’?” (Rosenberg 1998).

He was also astute enough to try to appeal to the larger audience in discussing these ideas, thereby becoming the name most associated with these concepts. “Descartes was well aware of his audience and wrote specifically for the ‘public’, rather than academics. From the outset, he wanted to address what he regarded as the outdated values of medieval thought, and the Discourse sets out his methodology for doing so. From the start, he attacks Aristotelian philosophy as providing no clear basis for truth, and sets out to show that the principles of mathematics are the only basis for ‘deductive reasoning’ (‘intuition’… ‘analysis’… ‘synthesis’… making the link from first principles to their consequences)” (Sutcliffe 1968). Although he had several ideas regarding natural processes, these were based upon the concept of the earth rotating around the sun, a premise for which Galileo was placed under house arrest and severe censorship. By delaying and restating his original thoughts, Descartes was able to get his main ideas out to the public while he had a chance to answer objections, but in such a way that it did not jeopardize his own freedom or religious loyalties.

There are generally two philosophical ideas brought forward by Descartes that is most widely known. These include his method of hyperbolic doubt and his often quoted ‘I think, therefore I am.’ Regarding the method of hyperbolic doubt, “he refused to accept the authority of previous philosophers – but he also refused to accept the obviousness of his own senses. In the search for a foundation for philosophy, whatever could be doubted must be rejected. He resolves to trust only that which is clearly and distinctly seen to be beyond any doubt. In this manner, Descartes peels away the layers of beliefs and opinions that clouded his view of the truth” (Burnham & Fieser 2006).

Mathematical concepts had not been applied to the school of philosophy previously because the formalist paradigm of the Socratic-Platonic denied the possibility of empirical knowledge. “On this view, the sensory experience can inform us only about appearances, about how things seem. Authentic knowledge (episteme), however, must be of reality. The idea of empirical knowledge, that is, experiential knowledge, is thus intrinsically incoherent. The provenance of knowledge proper, that is, knowledge of the eternal and independent Forms, is reason alone. With regard to the world available to us through the senses, the world of appearances, we can aspire only to opinion (Doxa)” (Rosenberg 1998).

It was through this thought process of eliminating all knowledge that had even a suspicion of being based on the opinion that Descartes arrived at his thought-provoking statement “cogito ergo sum” generally translated as meaning “I think, therefore I am” (Wikipedia contributors 2006). This most often quoted of his statements was published in his book entitled Discourse on Method in 1637. This simple-sounding statement is the result of a discourse in which Descartes calls into question all of the assumptions he’s come to know as a result of the philosophical thought of his day. “I had long before remarked that … it is sometimes necessary to adopt as if above doubt, opinions which we discern to be highly uncertain” (Descartes, 2001).

Through this questioning process, he demonstrates how thought, not observation is really the right foundation for knowledge. “When I considered that the very same thoughts (presentations) which we experience when awake may also be experienced when we are asleep, while there is at that time, not one of them true, I supposed that all the objects (presentations) that had ever entered into my mind when awake, had in them no more truth than the illusions of my dreams” (Descartes, 2001). His idea of discovering truths about the world was defined by whether he had a clear and distinct perception of them and determined that was sufficient for knowledge. To determine what constituted a clear and distinct perception, he then went on to examine what it was that formed perceptions, a mind-independent from the impressions of the body or the combination of the instinctual sensations of the body – ‘the set of limbs called the human body’ or ‘not lodged in my body like a pilot in a vessel’.

However, the idea that knowledge can be defined by a “clear and distinct perception” is foiled by its own dependence on the senses. Descartes argues his way out of this idea by indicating that in order to fool a mind, a mind must first exist. “But there is I know not what being, who is possessed at once of the highest power and the deepest cunning, who is constantly employing all his ingenuity in deceiving me. Doubtless, then, I exist, since I am deceived; and, let him deceive me as he may, he can never bring it about that I am nothing, so long as I shall be conscious that I am something” (Descartes, 1989). Regardless of the way in which it’s presented, though, there is a hole in the logic that states thought instead of the senses is the basis for truth while the evidence of correct thought is a clear and distinct sense that what is thought is correct. In his arguments regarding the nature and existence of God, Descartes goes on to say that it does not matter whether we are dreaming or not because whatever our intellect tells us is true is, in fact, true. This directly contradicts what he said earlier regarding dreams being little more than impressions that did not exist and did not necessarily represent what was true.

For a more modern and visual explanation of this concept, one need only turn to Hollywood’s production of “The Matrix” (1999). In this film, the main character, Neo, is under the impression that he is a computer programmer in a familiar world of corporate powerhouses and urban rat race, the average human being who bases his reality on a summation of his perceptions, the old philosophy. However, as the movie develops, it is explained that Neo’s perceptions are being controlled by a machine through super advanced virtual reality technology, none of what he knows as real is actually real, all of his sensations have been fooled all of his life, Descartes’ concept of a being ’employing all his ingenuity in deceiving me.’ At the same time, though, Neo does exist outside of this virtual reality world. This represents Descartes’ concept of the mind is free of sensations. This concept that a mind can exist independently from the sensations of a body is what leads to Descartes’ statements regarding the concept that his individuality, his soul, is something distinct and separate from the body.

Therefore, in pursuing a definition of the truth, Descartes came around full circle. From denying the existence of everything that had the shadow of a doubt, including everything known through the senses and seemingly intuitively, he argued his way through the idea that thought completely separated from sense was the necessary basis for knowledge and that the only correct thought was thought that carried with it the sense that it was clear and distinct. “He developed a dualistic system in which he distinguished radically between mind, the essence of which is thinking, and matter, the essence of which is an extension in three dimensions. Descartes’ metaphysical system is intuitionist, derived by reason from innate ideas, but his physics and physiology, based on sensory knowledge, are mechanistic and empiricist” (Watson 2002). Through the meditations included in Meditations on First Philosophy, Descartes presents his logical sequence leading to the idea that since God exists, all knowledge must come from him, and therefore, whether we are dreaming or awake, our perceptions of our reality must be real. It’s a self-contradicting circle that simply doesn’t make sense when taken in its entirety.

To seek a higher version of the truth, Descartes used logic to try to eliminate all his knowledge of the world and himself that had been gained through observation or the senses. His idea of discovering truths about the world was defined by whether he had a clear and distinct perception of them and that was sufficient for knowledge. He argues out of having to examine information brought in by the sense by arguing that a mind must first exist before it can be fooled by such things as sense perception. However, there is a hole in his logic that is better understood with a closer examination of logic itself. There can be no logical or rational connection between a statement of cognitive process versus a statement of a causal relationship.

The cognitive process can not be logically linked to a pre-existent existential condition. “Logic is best used for establishing relationships, causal, linguistic, or otherwise. It is good for communicating specific details of information relevant to the parties involved in the communiqué’ and falls under a category … which is quantitative in nature as opposed to qualitative” (Silar, 2007). To facilitate the discussion, terms such as ‘reasoning’ and ‘rationale’ are used to refer to two separate issues. ‘Reasoning’ is generally considered to mean purposeful thinking and ‘rationale’ is what a person place or thing/event is called that exhibits purposeful actions/thoughts. One of the dangers of logic is its circular nature. Generally, if one finds a high probability that ‘A’ will precede ‘B’, there is a tendency to assume that the presence of ‘B’ will necessarily indicate the existence of ‘A’. Because each is seen to be inextricable from the other, a circular relationship is formed that becomes difficult, if not impossible to break. There is no room for objection in this statement nor is there any room for doubt. If the first statement is held to be true that circular logic works, then the second statement must be true that circular logic works, and no further proof is needed. By examining the universe in just the right way, one can manage to prove just about anything, but this doesn’t mean it is any closer to being accurate.

Although Descartes’ arguments were revolutionary for his time and helped to introduce an entirely new way of thinking about the world, when examined closely, there are holes in his logic. The primary issue at stake is Descartes’ claim “I think therefore I am”, which is based on the idea that, because he has a mind that can either be deceived or can perceive through the senses, regardless of what those senses tell him, he must exist because they are there. As has been demonstrated through the examination of a logic circle, this statement is much like saying the string is a string because it is a string. There is no room for dissent or contradiction, suggesting that this statement has at last found a foundation of empirical knowledge. However, closer examination reveals that Descartes might as well have said dragons exist because dragons exist logically speaking. Recent science has revealed that there is no possibility of separating the senses from the mind as they are interdependent upon each other. At the same time, it is patently clear that sensational knowledge cannot be compared with empirical knowledge as they spring from different sources. In the end, one must come to the conclusion the Descartes’ most famous saying, I think therefore I am, simply does not make sense.


Baillet, A. (1693). The Life of Descartes. London: Printed for R. Simpson at the Harp in St. Paul’s Churchyard.

Burnham, D. & Fieser, J. (2006). “Rene Descartes: 1590-1650.” The Internet Encyclpedia of Philosophy. The University of Tennessee – Martin. Web.

Descartes, Rene. Meditations on First Philosophy. Trans. John Veitch. New York: Prometheus Books, 1989.

Descartes, René. Discourse on Method. Vol. XXXIV, Part 1. The Harvard Classics. New York: P.F. Collier & Son, 1909–14;, 2001.

Kandaswamy, D. (2006). The Key to Geometry: A Pair of Perpendicular Lines. New Brunswick: Rutgers Mathematics Department.

The Matrix. Dir. Andy Wachowski and Larry Wachowski. Perf. Keanu Reeves, Laurence Fishburne, Carrie-Ann Moss, Hugo Weaving, and Gloria Foster. Warner Brothers, 1999.

Rosenberg, J.F. (1998). “Descartes’ Skeptical Argument.” Logical Analysis and History of Philosophy. Vol. 1, pp. 209-32.

Silar, Gina. (2007). The Hundredth Monkey Speaks. Michigan: University of Michigan.

Sutcliffe, F.E. Introduction to Descartes, R. (1968). Discourse on Method and The Meditations. London: Penguin Books.

Vincent, J. (2003). “Rene Descartes: 1596-1650.” Island of Freedom. Web.

Watson, R. (2002). “Rene Descartes: 1596-1650.” The Encyclopedia Britannica. Scottsdale, AR: Pearson Software.

Wikipedia contributors. (2006). “Cogito ergo sum.” Wikipedia, The Free Encyclopedia. Web.