As I delve into the Cogito: Part oneSo, I've been researching the Cogito. Naturally, a good starting point is Descartes' epistemology and his Meditations.
He opens the First Meditations by arguing that he needs to demolish everything and start from the foundations:
Reason now leads me to think that I should hold back my assent from opinions which are not completely certain and indubitable just as carefully as I do from those which are patently false. So, for the purpose of rejecting all my opinions, it will be enough if I find in each of them at least some reason for doubt.
This is what I have managed to gather so far:
Descartes was a foundationalist, while he believed that some beliefs may be justified by others, there are also some other beliefs that are basic. Let’s say that we have some belief
A which in turn is justified by some belief
B which is justified by
C… until we get down to some belief which is justified by itself, a self-justified basic belief, this is the belief that Descartes is searching for.
These beliefs will have the properties of being: indubitable, true, error free in derivation, self-justified and infallible. In order to find these beliefs, Descartes tries to launch the most sceptical arguments he has at his disposal and create a very high bar for knowledge.
The first target he has in his search for basic beliefs is our beliefs about sense perception.
Descartes will present three sorts of sceptical argument: One that is too weak, one that is too strong and one that is “just right”.
The
too weak argument: Our sense perceptions may be flawed in the same way that they are flawed when we look at optical illusions. This is too weak because it only challenges one of our perceptions, vision.
The
too strong argument: The thought that he is a madman; he has no rationality and no sense. This is too strong, because if it were true, at no point would Descartes be able to reason that he is a madman.
The
just right argument: An argument dealing with the idea that Descartes might be dreaming. When you dream, all of your senses seem to function perfectly well, until you realise later on that you were dreaming.
This argument is stronger than the one from optical illusions because it affects all of your senses but it is weaker than the madman because at a later point you will of course realise that you were dreaming.
After these three arguments, Descartes believes that he has dealt with the notion of sense perception and that it can’t be a basic belief.
Topic: Cogito Ergo Sum