Validity of knowledge

Today I learned

About Descartes and his philosophy

The most important thing, for me, that Descartes does is search for an ultimate truth. One that is self evident, that which exists, and doesn’t need anything else to exist.

He does arrive at it - ‘I think, therefore I am’. Cogito, Ergo Sum. Whatever may or may not exist, whatever may be an illusion, there is one truth - the truth that I doubt the truth of other things. I, in fact, doubt the fact that I doubt. Nevertheless, to raise this doubt, there must exist a doubter – me. Therefore I exist, the thinking, conscious me.

To my utter shock, this isn’t really the ultimate truth. This claim of standalone, independent knowledge, like every other claim you are probably ever going to hear, depends on other claims. Firstly, substances (for example, I in the ‘therefore I exist’) must exist. Secondly, it must be true that thinking must be associated with this substance - i.e. a thought must not be able to exist by itself without the thinker. As empiricists simply ask, ‘How do you know?’ So, it isn’t all that ultimate, is it?

So, what is the knowledge anyway, when even the very fundamental truth may not be what it seems?

You can go 'The Dude' way to almost any claim - "Yeah, well, you know, that's just, like, your opinion, man". Now, if you want to argue with 'The Dude', you must be awesome enough to use six commas in a sentence!