In Western philosophy, skepticism is the movement represented by Descartes, one of the most prominent French philosophers. He introduced the concept of skepticism which doubts the external world. He distinguished sense and mind from the physical world and body. He suggested that the external world could be simply an illusion. Moreover, Descartes presented the Evil Demon argument as an attempt to establish a solid foundation for knowledge. After, his ideas have been discussed in detail as the contemporary response to Cartesian skepticism.

Descartes’ Evil Devil Argument

Descartes attempted to explain the fundamental principles of scientific approach introduced by Galileo which had received popular approval. In addition, he was willing to show the consistency between the modern scientific methodology and Christianity without attacking any of those notions. Descartes presented two essential goals in his works. Initially, he considered that the scientific method should receive more attention. The philosopher aimed at expressing the genuine source of the scientific knowledge that did not originate from the senses, but in mind. Secondly, he attempted to disclose the compatibility between the religion and science. In fact, Descartes divided the world into two opposite substances, namely body and mind, to coin his theory. It suggests that the religious truth is related to the soul while the science deals with the entire accuracy of the body, particularly its comprehensive matter.


Taking into consideration the fact that science is based on mind, not the senses, the philosopher doubted the beliefs the person could form through the senses. This argument assisted him in establishing the fact that nothing exists in reality. In particular, it appeared impossible for people to recognize whether anything was present in the world genuinely. Descartes stated that the external objects could be understood later. At the same time, he showed that the knowledge about anything in the world perceived through the senses was ambiguous. Thus, if people had gained the scientific knowledge through their senses, the existence of objects and theories outside would have been doubtful. Therefore, the distinct connotation appeared. The existence of the external objects was obvious due to the fact that the knowledge was based on the mind, not on the perception of an individual.

Descartes decided to question the knowledge by applying three arguments: the dream argument, the deceiving God argument, and the evil demon argument. The fundamental principle hidden in these arguments is in the fact that people do not regard the external objects simply. On the contrary, they perceive everything through their minds where the images of the external objects have been already created. The sense perception gives no certainty that the images existed in our minds correspond to the real objects present in the external world. Therefore, Descartes’ arguments become an attempt to challenge the mind according to the experience it has from the senses.

According to the evil devil argument, the philosopher claimed that instead of presuming that the source of the deceit comes from God, people naturally assume that has an evil demon nature. Thus, the latter could deceive people in the identical manner as they deem that God is able to do. Consequently, it leads to a new doubt whether the sensual responses are similar to the mathematical knowledge the person can acquire. Obviously, the sense could not appear as the source of the knowledge. For that reason, Descartes overhauled the edifice of knowledge regarding the materials and resources found in the content of mind. Judging from that idea, the sole concept the philosopher could have believed in was the fact of his own existence.


Definitely, Descartes’ thoughts on the perception of the external world were primarily based on the knowledge in the realm of doubt. Implementation of his method intended to establish a firm foundation for knowledge that became foundationalism. Its central idea is to arrange the theories structurally in correspondence to the justification edifice which should possess the integrity. It is characterized by the solid foundation as well as a superstructure of approval insights on the theories of the world. Therefore, two analogous characteristics might arrange the system of justified beliefs. In fact, it is a foundation of firm principles and a superstructure of the forthcoming proposal attached to the foundation through the firm inference.

Henceforth, Descartes stated that Euclid’s geometry was an example of the foundationalist system. The mathematicians commenced structuring the knowledge with establishing the fundamental principles such as axioms, definitions, postulates, and others. They gathered facts in order to form the logical explanation to their theories.

Among Descartes’ principal ideas is the one that the preconceived opinion influences the personal mental vision of innate principles by obscuring it. Consequently, the philosopher claimed that it should have been repealed. Unless it was done, the principles formed without enough knowledge and experience might have been regarded as erroneous. As a result, the mistakes in foundation diminish the complete justification edifice.

Eventually, foundationalism allows to extend knowledge from the initial principles. Descartes considered that the complementary approach assists in discovering the absolute insights since the axiom is inevitably obscured by the biases of the senses. For this reason, the philosopher created the method of doubts to acquire the essence by rejecting preconceived viewpoints.

Contemporary Response to the Cartesian Doubt

Studies of Descartes’ methodologies are discussed in the reference to the Cartesian doubt. This type of doubt is regarded as a concept of the methodological skepticism. Moreover, it is a systematic process of constant doubting the accuracy of the beliefs in order to define the absolute truth. The contemporary analysis of the problem focuses on the formation of the skepticism concept with the regard to paradox which comprises three claims that appear as the external notion of things. They are examined individually.

Primarily, it is impossible to denote false skeptical hypotheses. It is recognized as an internally indistinguishable form from the person’s view on the ordinary circumstances. However, if it is true, it may influence the knowledge an individual develops. For instance, “brain-in-a-vat” (BIV) is the hypothesis that states that a person discovers world via the computer experience. Acceptance of this hypothesis means the recognition that the personal beliefs about the world are artificial. Consequently, an individual might not have an actual knowledge. However, it is almost impossible to understand the roots of one’s knowledge. As a result, it leads to the primary intuitive aspect of the skeptical paradox: “I am unable to know the denials of skeptical hypothesis.” The second skeptical paradox is “If I do not know the denials of skeptical hypothesis, then I do not know very much.” It means that one may comprehend his false understanding of the world. Unfortunately, a person starts doubting his own existence. The third paradox states that “a lot of I believe, I know” is excessively credible claim because the truth cannot be a mistake.

In conclusion, Descartes regarded the external world through the prism of skepticism. He rejected the sensual perception of the facts around him claiming that they should be only the individual illusions. Besides, the philosopher believed that the word could be explained by the foundation of scientific knowledge. In fact, the critical responses to Descartes’ ideas and works have been stated in the Cartesian doubt that expresses the contemporary opinion on the philosopher’s understanding of knowledge and sense.

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