Method of Doubt by Descartes

Rene Descartes, the father of modern philosophy, adopted the method of doubt to reach the truth. Descartes’ philosophical attitude started in his youth when he realized that he had been accepting many false opinions for true. He wanted to get rid of all the opinions that he had accumulated over the years. Descartes wanted to build a foundation on which all further intellectual enquiries could be built. He felt reason should follow and arrive at certain philosophical truths. There should be no further doubts left after this, which meant that the foundation had to be sound. This approach was known as the Method of Doubt but his rationale and approach has been a subject of controversy for years.

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He believed never to accept anything as the truth, which he could not accept as obviously true. Everything should be so clearly presented to the mind that there are no doubts left at all. Anything that can be doubted has to be rejected. Reasons to believe something should be ample. The second step is to divide the subject into as many divisions as possible or whatever would help him to understand it better. The third step involved directing his thoughts, taking one step at a time, to reach the underlying complex knowledge. At the end of this, his reviews were so comprehensive, his enumerations so complete, that nothing was left to doubt.

The three steps adopted by Descartes is what is adopted in mathematics. He wanted to use this method to reach the truth in philosophy. S V Keeling argues that his method as above rests on three mental operations – intuition, deduction, and enumeration (cited by Burnham, 2006). These operations are based on human reason, on the ability to disseminate information, analyze, and review. Since it is based on the capability of human mind, there is a risk of error due to faulty memory.

In the Meditations on First Philosophy Descartes proves the existence of God and the immortality of the soul. He also brings out the real distinction between the mind and the body. He starts this by asserting the need “to demolish everything completely and start again right from the foundations” (AT 7:17). Although the first step was termed as skeptical his skepticism was not for the sake of doubting. He wanted to arrive at the truth through systematic analysis and discarding the untruth. Descartes defines knowledge in terms of doubt:

I distinguish the two as follows: there is conviction when there remains some reason, which might lead us to doubt, but knowledge is conviction based on a reason so strong that it can never be shaken by any stronger reason (cited by Norman, 2005).

Descartes skeptical approach is based on the principle that there is a distinction between belief and truth (Bellotti, n.d.). It was this conviction that gave rise to the Method of Doubt. After making a cup of tea one may leave it to brew on the kitchen table under the belief that it is ready to be poured and consumed. The truth may be different from the belief, in the sense, someone could have poured the tea and taken it in the meantime. The pot may be empty by this time. The Method of Doubt removes all uncertain beliefs and only beliefs that are true beliefs remain. Descartes applied this theory to a group of beliefs so that beliefs need not be dealt individually. A common characteristic could be determined but this concept again leads one to believe that doubts would be on the entire group or class of beliefs. Here Descartes uses the malicious demon thought experiment.

Gassendi criticized this theory saying that Descartes could just have regarded the previous knowledge as uncertain (cited by Norman) instead of demolishing everything. It is not necessary to consider everything as false. He felt that such an approach convinces the human mind that there is a devil who tricks us. It is simpler to admit the weakness of human nature. Gassendi pointed out the universal and hyperbolic nature of the Method of Doubt. Descartes argues that it is not possible to free ourselves of all the errors that the human mind has been soaked in. He firmly believes that universal and hyperbolic nature is necessary for the Method of Doubt to succeed.

Descartes in his argument to demolish everything and start afresh applies the universal character and gives the analogy of a basket full of apples. To select and retain the good ones and discard the bad ones, it is wiser to empty the basket, then select the good ones and keep them in the basket. He feels this is a better and simpler way than picking out the rotten ones from the basket full of apples. He believes in first rejecting all beliefs as if they were false and then after careful analysis, adopt only the ones, which are true. One bad apple can rot the whole basket so if we were to pick out the bad ones, there is every possibility of overlooking one bad apple. On the other hand, if the whole basket is first emptied and then the good ones placed back, we can be sure of only adopting the truth. Descartes’ method of doubt, as foundation of knowledge does seem more effective than what has been suggested by Gassendi. When the basket is totally empty, it can be cleaned and then fresh, good apples picked and placed in the basket. It is a much faster process than negating the bad. Secondly, when the basket is empty, the stains left behind by the rotten apples can be seen and cleaned, which is not possible when the bad apples are picked out from the lot.

His argument to discard everything as false relies on his argument that the mind believes on whatever it perceives through the physical eye. He did not believe that anything should be left to imagination. This has a sound basis, as the mind cannot imagine what it has not seen. In order to support that all prior beliefs are wrong, he discussed three stages – the sense, dreams and the evil demon hypothesis. Descartes asserts that these do not have the power to falsify what we ‘seem’ to perceive. What we see through the sense mislead us. We cannot begin with doubt. Descartes even goes to the extent of affirming that even the external world that we perceive is an illusion, a dream and hence false. The enquiry has to start after eliminating all such perceptions.

The next argument that arises is whether the escape from hyperbolic provides a satisfactory foundation for knowledge? This can be explained by an analogy of a building, which requires the use of a bulldozer to demolish it. A light bulldozer would make the ground appear immovable. Hence, a bigger bulldozer is more effective, which means the more hyperbolic the doubt, the better it is. According to Descartes, the Evil Genius Doubt is the most powerful doubt. This evil genius makes us believe the false as true. For instance, the transparent truths like 2+3=5 or that a square has only four sides, are knowable. For people to know, understand, and accept these truths, they have to be firmly grounded in the face of the most powerful doubts. The evil genius tries to shake even such hyperbolic doubts. People also firmly deny the existence of God. Descartes believes that the Evil Genius Doubt is just one of the factors that can motivate the hyperbolic doubt. The basic doubt is that the human mind is flawed, and the mind is aware that it has been distorted despite God having given a nature to turn to him. The human mind keeps remembering all the past incidents and visions, and gives them the right to occupy the mind. It is not easy to accept that the world we see everyday is an illusion. It is only through deep introspection and a strong will that a person can accept the truth that God exists and all else is false. He has to be fixed in this belief and arrive at the knowledge of truth. He has to arouse himself from the deep slumber of falsehood. The more hyperbolic the doubt, the mind is activated better.

Hence, the best approach is to discard everything as false and start afresh. Descartes’ philosophical approach through the Method of Doubt is a sound method. It is in fact the best approach to investigation. It is an investigation of the self by the self to reach the self or the truth. To reach the truth, through the Method of Doubt, an individual has to negate the external world around him. If he feels this world to be true or feels a part of this illusionary world, he can understand or realize the existence of God. The program of demolition is not only hyperbolic but also universal in nature. To face the Evil Genius there has to be an equally powerful doubt. Escape from hyperbolic cannot provide a satisfactory foundation for knowledge.


Bellotti T (n.d.), Descartes’ Mehod of Doubt, 01 April 2006

Burnham D (2006), The Internet Encyclopedia of Philosophy,

01 April 2006

Newman, Lex, “Descartes’ Epistemology“, The Stanford Encyclopedia of Philosophy (Summer 2005 Edition), Edward N. Zalta (ed.), URL 01 April 2006