Descartes Meditation I

In Descartes Meditation I, he casts doubt as to whether or not we are dreaming. He first uses modus tollens to cast doubt to our senses. He then he uses redictio ad absurdum to show that even if we are dreaming, there are some things that are still real.

Descartes begins with establishing the key idea of laying a strong foundation for his ideas. He acknowledges that he has preconceived ideas about the world in which he can doubt their truth. He sees this collection of ideas as a pyramid, where his core values and opinions serve as the base for every other idea. He proposes that he should scrutinize his foundation, namely his existence, because proving it false will undermine the truth of any idea built on it. He is saying that if he could destroy the base of the pyramid, then every brick resting on it will collapse.

Descartes then states that all of his beliefs have either been obtained through his senses or through interpretations of his senses. However, he finds that his senses are not reliable, giving an example of a naked madman claiming to be wearing clothes. Using modus tollens, the madman believes that he is wearing clothes; it is obvious from his nakedness that he is not wearing anything. Clearly, the madman's senses are deceiving him, and thus cannot be relied on. Descartes then applies the idea of distorted senses to a more common application of dreams. In dreams, the dreamer cannot be sure of whether or not he is dreaming. Although he may try to test his senses, such as touch or movement or vividness, Descartes claims that he has done similar tests while he was actually dreaming. It is possible that a dreamer can have his senses experience the exact same feelings as if he were in the real world, while he was dreaming. Descartes concludes that it is difficult to use one's senses to realize whether or not one is dreaming.

Since Descartes cannot prove that we are not dreaming, he makes the assumption that he is in fact dreaming, and that he may or may not have the body he sees. He points out that although he cannot tell whether the images he sees actually exist; they have basic properties in common that must exist in reality. He uses the example of a painter who paints a portrait of a centaur, a mythical beast which is a combination of a horse and a man. Even though the centaur does not exist in reality, he has properties of objects that do exist, namely a man and a horse. Even though he may be dreaming, all of his ideas contain core properties, such as color and quantity, which must be real. Because these core properties deal with simple and abstract ideas, they can be combined to form more complicated and new ideas. Also, because they are general, they do not become false under any amount of scrutiny. He therefore concludes that no matter how much our imaginations and senses toy with our conception of reality, they will always be rooted in some truth.

In order to prove that we are not dreaming, Descartes uses the indirect method of reductio ad absurdum. Since he cannot directly prove that we are not dreaming, he assumes the opposite is true, that we are indeed dreaming. It is assumed that if we were dreaming, then we were imagining all of the events and experiences. That would imply that we do not know anything to be real. However, he shows that there are some concepts that are real, such as arithmetic and geometry, which hold to be true regardless of any object's existence. Since he proves that there is some truth in all that we imagine or dream about, hence the idea that we are dreaming is false. Using this reasoning, he concludes that we are not dreaming.

Descartes' "dream" argument does not give me any inclination to believe that we are indeed awake. In his argument is unsound because he claims that if we were dreaming, then our dreams would be rooted in reality. As said before, Descartes claims that since we know certain truths, such as mathematics, we cannot