Descartes uses several methods of using sceptical doubt to prove his quest for knowledge or certainty. He takes the position of a functional sceptical to initially doubt knowledge so that by using an Aunt Sally technique, he can destroy the argument and submit his genuine argument for knowledge. He however overlooks some major points and there are flaws to his thought processes. Descartes initially states that many of his common sense opinions are incorrect, filled with error and prejudice.
He sets out to discover knowledge that is undeniable and unquestionable.He says that he is going to strip himself of all his former knowledge and start back from the basics and try and set up from the foundations on which to build a body of knowledge. Descartes starts by taking the position of a Functional sceptic. He takes up the argument against the idea of knowledge.
He says that he will not try and destroy every belief or claim to knowledge individually which is “an endless task” but will attack the fundamental concepts and basic beliefs, causing all other claims to collapse as well, leaving and claims which are indubitable left, securing a firm basis to knowledge.He first suggests that because his senses sometimes fool him, he cannot rely upon them to gain certain information. He says ‘It is prudent never to trust entirely those who have once deceived us’. This statement attacks one of the basic and common mechanisms that the empiricist uses to gain knowledge. It doubts that any information that the five senses give us is reliable and sufficient to gain certainty from. However this is an incorrect conclusion and his argument is self refuting.
His premiss, “My Senses sometimes fool me” cannot lead to “My Senses could always be fooling me”.The only way that we can relise that our senses sometime fool us, is that they are not deceived for the majority of the time and only in certain instances are deceived. If they were always fooled, we could not differentiate when they are fooling us and when they are not. His argument is self refuting because in the premiss he says the senses are “Sometimes” fooled which indicates they are not deceived for the majority of the time. Descartes however could rebuttal that his intentions were correct. If they can sometimes fool you, there is no definite certainty that they are not fooling you know, although it is unlikely.
The knowledge he is seeking is for definite certainty and is right in the fact that your senses cannot do that. Descartes moves to the second wave of doubt which pushes the process of doubt even further. He says that he “often has dreams which are very like real life and that he is unaware that he is dreaming”. This again attacks the empiricist and strips him of the fundamental experience to gain knowledge. The fundamental criticism with this argument is that it is self refuting.
He says “I am sometimes unaware I am dreaming” which he then leads to “I may always be dreaming”. This is a contradictory statement.You could also point out that the definition of a dream is “a state of mind characterized by abstraction and release from reality”. This therefore means that if all life was a dream, there would be no reality, nothing to differentiate between reality and a dream with. Thus making a dream not a dream, this shows Descartes Aunt Sally argument does not function correctly as a skeptical argument. Again his first premiss “Some dreams are indistinguishable” is a paradox.
For him to say that his dream is undistinguishable it must be distinguishable or he could not ever know he had that dream.So the premiss cannot be true and is false. He later defeats his own Argument for Dreams by saying even in a dream, you cannot see a 4 sided triangle and logic, reasoning and language is not affected in a dream, still allowing you to gain a priori knowledge from which you can gain certain knowledge. Descartes then introduces his 3rd and strongest argument against knowledge, the idea of a Malicious Demon. He says that a demon controls our minds, deceiving us about the existence of the world and our own body.He continuous to say that the demon could even be controlling our minds, thought and logic.
This completely strips all methods of how we gain experience, a posteriori methods cannot be used and neither can a priori. This is the main mistake Descartes makes in his quest for certainty, he creates an undefeatable argument. The argument against knowledge that he creates in this large Aunt Sally, is much greater than his actual argument for knowledge.
He defeats the one thing he is trying to do. Descartes believes he has a solution to his argument.He suggests that “I Am, I exist”. Because he is able to doubt, there must be something that is doing the doubting, and therefore he exists. However this solution is flawed for one reason, that he is using his logic to deduce this. Descartes believes he has defeated the malicious demon and therefore has set the base on which to build his argument for knowledge.
However in truth, the skeptical argument against knowledge still stands, preventing any arguments for knowledge to exist. This means that everything else he starts to create off the statement is unjustified.This flaws his progression to find absolute certainty of knowledge. In conclusion, Descartes has a very good method on which to discover absolute certainty. His plan to destroy all foundations of knowledge which allows him to rebuild his ideas upon is a very good way to gain certainty. However he overlooks some major points and there are flaws in his thought processes.
He almost rushes through the initial skeptical argument to show his actual argument and does not fully explore the possibilities. This halts his ultimate progression in his Quest for Certainty.