Historical Introduction to Philosophy/Descartes Scratch Page

Historical Introduction to Philosophy

Rene Descartes


Descartes was a leading figure in the scientific revolution of the 17th century. He helped shape the “new science” or the worldview that the universe was a heliocentric system, meaning that the sun not earth and humans were at the center of the universe. Also, that the world could be explained using reason and mathematical specifically geometric equations.

Descartes used a method of doubt to find undisputable truth and explain how the universe worked. In order to accomplish this he must define knowledge. He relates knowledge to a tree with the roots being the foundation, physics the trunk and the branches are ethics as well as the other sciences. He believed that, if he doubted something even once, it could not be 100% certain.

List of Works The World 1633 (never published)

Dicourse on Method 1637

Meditations of First Philosophy: In which the existence of god and the real distinction of the mind and body, are demonstrated 1641

Principles of Philosophy


Descartes was largely influenced by Plato, Pythagoras, Anselm, and Aquinas, and rejected the Aristotilian world views the church so fiercely held onto. Descartes' findings findings inspired Spinoza, Libenz, Locke, Hume, and most any of the modern philosophers have been influenced by his work. Wheather or not they agree with him is another matter.

Descartes was responding to Aristorle, Aquinas, Anslem

Philosophical Contributions Discovered Analytical Geometry Cartisiean Coordinates Cartisiean Dualism

Arguements Cogito ergo sum Mind/Spirit/Soul The existence of god The Evol Demon

Synopsis of philosophical thought

Methods Method of doubt Geometry - clear and distinct proof

Brain in Vat arguement


On the night of November 10, 1619, alone in a room with no distractions he sat in front of the fire to begin his famous search for the truth. He cast aside his beliefs by using a method of doubt. In order to get to the Truth he must cast doubt on his opinions and their foundations. This method had four rules. First, he suggested that the search proceed slowly and meticulously. This could be accomplished by breaking the parts of each supposed truth into small parts then rebuilding with 100% certain knowledge. He acknowledges that what he knows about the world before his great quest came from his senses. He was also aware of the fact that our senses can deceive us and give us false information. He argued that an evil demon must be the deceiver and this miline gienie can even chase us in our dreams.

Discourse on Method

The Meditations In the first meditation, Descartes refers to much of the information contained in his discourse of method. By way of self analysis he comes to the conclusion that he has a soul. He says “I will doubt not only what is obviously false, but what is even slightly doubtful.” He looks at his hands and realizes that they must be his and the he would be crazy not to think so. He admits that the fives senses can deceive man. He casts away his former beliefs and asserts that he will doubt anything and everything he knows.

Descartes’s famous cogito ergo sum argument is the main focus of the second meditation. He asserts that what he sees is not to be trusted, his memory is suspect, he has no body, and no senses. So, what is he? Descartes then asserts he must exist and that some heinous demon must be deceiving him by way of the senses. Enter the “I think therefore I am.” How can he doubt that he exists, after all, he does think. He explains the “I” by using wax as an example. He studies a candle noting its size, shape, sound… next he heats the candle in the fire observing then change after it melts. He concludes that the candle has changed but that the wax is the same. This knowledge he believes is innate, something we can only get to by intellect.

The third meditation contains his argument proving the existence of god. The argument is weak, but accepted by many. Descartes asserts that ideas are like atoms, they crash together when we are thinking. He proves god’s existence by saying that god is a perfect being, and that humans are imperfect. An imperfect being cannot create a perfect being therefore god is real. Descartes uses the next two meditation s to reaffirm this argument.

In the sixth meditation Descartes addresses the mind body problem. Asserting again, that the senses cannot be trusted with absolute certainty. He also concludes that he is a thinking being, and that his mind is not extended. He asserts that the body is extended, meaning that it takes up space thus separating the mind from the body. He reasons that there must be something outside of the mind and body that causes sense perception. This something Descartes concludes is god. For God is good and would not deceive poor little man.

Descartes moves to explains true understanding. He does this, using mathematical examples. If a square has four sides humans can understand the concept of a square. On the other hand if 10,000 demons are standing in a room, humans must use imagination. Imagination is not an essential property of the mind so again god must have something to do with human perception. Descartes is to this day a great influence for many thinkers.