Descartes had realized that humans ability to observe the world around them, mainly the senses, were susceptible to misinterpreting the input that was received. This is exemplified in the line "I received either from or through the senses. I observed, however, that these sometimes misled us..." from the third paragraph of Meditations I (Descrates). An example of the interpretations of our sense being wrong would be the mirage seen on the roads in a hot summer day. Sometimes these mirages make it appear that there is water on the road surface at a distance away.
When Descartes states "I am; I exist" is a phrase that is more commonly associated with "I think, therefore I exist. What he is stating that up until this point he believes it is possible that what we perceive is a deception. But in order for that to happen, he would have to exist in order to be deceived. Descartes does admit further into the Meditations II that all he is sure of that he is a thinking thing, that his physical state could still be in question. This is shown when he says "I am therefore, precisely speaking, only a thinking thing, that is, a mind." (Descrates).
So when Descartes uses "I" he is referring to the thinking self. He is referring to the mind because that is the only thing that he can be sure that is real. His argument is that his perception of a physical body could be a deception, however in order to be deceived he would need to be able to think. So in his belief, the only thing that he can be sure actually exist is his ability to think. While it is circular logic in a way, that does not make it any less plausible.
PROFESSORS RESPONSE:
Matthew, you make interesting points in your post. Descartes' distrust of sensory experience as a means to truth is perhaps understandable, yet how are we to make the leap with him to the confirmation of the supernatural? What method allows Descartes to make this assertion (there is a supernatural or a god), and did you agree with his logic in getting to his conclusion?
INITIAL POSTERS RESPONSE:
Sir,
Unlike today, with the common knowledge of virtual reality, Descartes had no concept of what could possible deceive his sense beyond something with powers beyond that of a normal human. This would naturally lead him to believe in a supernatural force. It is interesting that to this day, we has humans are still asking these questions. Physics Professors at Cambridge University and MIT have been considering the possibility that our universe is actually a computer simulation, and are in the process of trying to develop ways of testing this (Merali).
Given the knowledge that Descartes had at the time, his logic would be sound. No more than we could expect a Descartes to understand how flight works, could we expect him to understand that forces other than a supernatural entity could be capable of deceiving him. Show him a television with a show playing, and he could very easily mistake it for message from a deity.
STUDENT A's RESPONSE
Matthew,
You made some great points in paraphrasing a few of Descartes' ideas on rationalizing our existence. There were a few times where I saw and understood the same ideas you did. It seems that he constantly brought up different ideas to both prove and also disprove sensibility as to if we are actually real or tangible beings. I used the very same point in my response this week because I liked and agreed with it so much, that being we can only deceive our existence only therefore if we do actually exist. To me it seems as if some
points his arguments actually somewhat collapse on themselves.
Also, the very last portion of your response is, yet again, highly agreeable. I believe he went in quite a few circles to arrive at a point in which is very difficult to understand and make sense of.
STUDENT B's RESPONSE
Hello Mathew,
I agree that our senses deceive of at times, but we also understand and recognize false information, to a certain extent. Through experience, whether our own or others, we understand that our perception is skewed, and for example, that there is no water in the desert, just more sand.
I like how you rephrased Descartes statement from "I am; I exist" to "I think; therefore I exist." This simplifies Descartes very wordy writing into an easy to understand statement. Being able to question ones own existence is proof enough that one does exist. I noticed that he understood himself as something that thinks as well. Descartes poses questions as to what form he takes and quickly discredits himself and makes reference to being deceived, or having a false perception of reality.
I agree that Descartes is referring to the thinking self, but I disagree that it is his mind (that is if you are referring to a brain as we see it). I get the impression that Descartes is referencing "I" as his soul, and that the body that houses it is what he questions. Descartes mentions an all powerful being or God, and that is why Descartes exists. Descartes also mentions that he could be deceived into a false reality, but he exists and God has allowed him to gain control of his mind (Descartes). When Descartes mentions gaining control of his mind I do not think he means a brain, I think he means his soul.